Well, you have a measurable difference at a power input, but what will be the difference on audio output? I have no such thing as this, no fancy high-end equipment, yet, with no input, I can't hear s**t coming out of my DIY amp with ear right at the speaker. And not that my AC is clean - it's far from that.
@@tomkocur If I'd paid thousands or 10's of thousands (or even "only" several '00) for audio equipment which turned out to have such a shoite power supply that it couldn't cope with normal public power grid electricity I'd be pretty hacked off....
Definitely a better case and overall construction quality than that £25k POS Tom Evans preamp that got you the copyright strike, bit which is now all over UA-cam 😀
I dunno what it is but I find these videos informative AND relaxing! Always liked cooking shows and repairs! Seeing something go from useless to great! Thanks for the vids and positive attitude!
As someone that's watching these older videos after having watched most of the newer ones, I do find it interesting that, here, Mark is questioning the use of Kapton tape on transistors while in the Kinki amp follow-up video he defended it (with math!) Now I'm only sad that I'm nearly done watching all of Mark's videos. Incredible stuff!
Hello Mark! I just stumbled upon your channel and I instinctively clicked on the subscribe button. Your troubleshooting and subsequent repair of this "smoke and mirrors/snake oil" AC power regenerator (seriously... how silly) was Top Notch. Color me impressed. BTW, Kapton tape used as an insulator is mildly acceptable, depending on the heat transfer coefficient requirement not needing to be moderately fast, however I take issue with this tape having the ability to be in the same league of thermally transmissive mica, Sil-pads, etc. Kapton tape is coated with adhesive on the sticky side (obviously) and the formulation of this glue does not address having any thermally transmissive properties at all. Just because the Kapton tape is a good insulator does not make it a good thermal conductor. In my opinion, using plain old school mica wafers or the newer Sil-pads will provide much faster heat transfer away from the BJTs and the speed at which the heat can be soaked away can be quite critical, when a lot of current passes through the active devices. Just my $0.02 worth of unsolicited concern. Thank you for the video and you did a beautiful job of repairing this "thing". Fred
I personally have experience with these "things", and know what positive improvements I can demonstrate in terms of noise-reduction and clarity. Have you used one are are you just convinced they are not worth it? If so why, pray tell...
@@vicweast If you want to fight, you can check out the Audio Science Review. Basically, it doesn't make any sense unless your device's circuitry doesn't use DC, but directly AC. Any normal circuit's DC side should not be affected by AC in any way unless there are major power surge or blackout.
@@mattparker8747A good example is the late Siegfried Linkwitz (of Linkwitz-Riley filter fame) was a dedicated audiophile and an electronics engineer who designed instruments (Spectrum Analyzers etc) at Hewlett Packard for many years.
Nice video. Two bits of advice if I may... 1, put a sacrificial rubber sleeve over the tip of the solder sucker. It will suck better, and you'll degrade the tip with heat much more slowly. Change the sleeve once a week, or as needed. 2, only solder one pin on the power transistors to hold them. As you assemble back into the chassis, reflow that pin and then solder the others. This will remove just about all of the mechanical stress where the leads enter the resin package, which might prevent problems in the future.
@engjds When I was regularly using a solder sucker (1970s to 1990s) rubber sleeving was very common in wiring departments (made by Hellerman among others). I guess it's less popular these days.
Going way, way back to the first days of the PC, we would frequently have to give boards with an edge connector the "pink pearl" treatment. That is, using a Pink Prearl Eraser to clean the contacts. Worked wonders 90% of the time.
Agree! That ISA style connector on the PCB side was heavily corroded and as it created the AC waveform, I'd be surprised if it wasn't that which caused the issue in the first place.
To my experienced eyes, this whole thing smacks of having been (badly) repaired before hence the Kapton tape for SIL pad bodge. Kapton tape as SIL Pads, sorry not on my planet! Good video as usual chap, keep it up! A
You're right. Kapton tape is not thermally conductive; rather, it is known for its excellent thermal insulation properties. Made from polyimide film, Kapton tape can withstand high temperatures (up to about 260°C or 500°F) without degrading, making it suitable for applications in electronics, aerospace, and other industries where heat resistance is necessary. While it can tolerate high temperatures, it does not conduct heat well, which is one of the reasons it is often used as an insulating material. Keratherm Red 86/82 thermal pads are the way to go there. This material is a single solution - there is no need to use thermal grease - just place the insulator between the transistor and heatsink. The Keratherm Red material is silicone and fiberglass material impregnated with ceramic that is thermally conductive. In normal use it can match or even exceed the performance of mica and grease. It is ideal for Class-A and Class-AB power amplifier devices and anywhere you need a good thermal interface.
Kapton absolutely is used as a thermal pad. It's not the best performer but it works. Firts time I've seen it was a Cerwin Vega power amplifier. Rather serious heatsinks, forced air cooling, and all TO-3 transistors mounted on kapton insulators. Fischer Elektronik still makes a range of kapton thermal pads.
Its advantage as a thermal pad is that it is very thin, which more than makes up for the better thermal conductivity of a fat silicone pad. We used mica for years, and Kapton works better than that. The only benefit of silicone is that it is gap-filling so it doesn't need the addition of grease to conduct heat effectively.
No matter what kind of dodgy AC line power comes in to audio gear, the power supply in the audio equipment will clean it up- nothing bad will reach the speakers. These AC power conditioners do nothing to improve sound quality- everything it might do is down to placebo effect.
Way back in the day I dabbled quite a bit in electronics and I would run across a piece of equipment that had heatsinked power transistors. The manufacturers always used mica and heat sink paste.
Wow that was interesting to see that waveform clipped before you worked your magic on the PS Audio unit. I have never seen capton tape used before in that way and I worked in electronic manufacturing a long time. As you say there must have been a reason for it. Love your videos.
Mica insulators will give a grainy, mineral sound. The audio characteristic of silicone is too soft and rubbery. Kapton will produce a clear tight sound with solid bass and treble. Unfortunately beryllium oxide will cause severe attenuation of high frequencies and make your high end setup sound like a cheap telephone. Of course diamond is the superior heat transfer material of choice and produces no noticeable coloration, it is the best if you can afford it. Vacuum tube amplifiers do not require heat transfer pads. That is one of the reasons they have a superior sound
@@peterallen8413 At low frequencies the heat is produced in waves. Inappropriate transient properties of the heat transfer material will cause the bass to be severely distorted due to thermal effects on the output transistor junctions. Nonlinear dielectric loss in the stray capacitance will affect the high frequencies. Tighter clamping will make a noticeable improvement in sound.
1:00 That sinewave shape was like that thirty years ago, so IMHO has little to do with "modern" electronics. Conventional power supplies are just as guilty in taking power at the peak of the sinewave as switched mode power supplies are. I'm not too worried about the slightly distorted mains sinewave, my audio (and other) devices turn it into a regulated DC supply first anyway.
Its not actually the switched mode bit of the power supply that does that, its the rectifier, which has been used forever. SMPS can inject distortion into the net, just not harmonic distortion. Nowadays, there is more regulation on the distortion a supply is allowed to make, so I would imagine it would only get better, as long as we don't collectively buy unregulated imported electronics, which tend to omit most of the improvements, like power factor correction and EMI filters.
Yes, I get a nice waveform out of a ferroresonant converter, which also has a nice advantage that rectifier diodes run cooler due to the flat topped waveform, and it makes for a really good mains filter as well, surviving a few cycles of drop out with no hassle..
The cooling fan was an added on mod to combat overheating on these power plants. They usually ran very hot and weren't so reliable, as alot of PS Audio stuff was. The new newer power transistors they used were less reliable than the MJ1302/3281. I highly recommend a desolder station on these older double sided boards. Its easy to lift or damage traces on them with the "heat and pull" method.
I'm glad I found this channel. Delightful circuit repair ASMR with such calm and authoritative commentary; it's so relaxing and I just might learn enough to be able to repair my Arcam Alpha 9 integrated amp. Win-win!
Hi - easier to remove the transistor if you snip the pins first. You can then remove the pins one at a time without needing to overheat (and possibly lift) the pads. I'd also be worrying about clearances to the case around the capton tape. Presumably those power devices are at mains voltage - pretty sure there isn't 5mm of clearance there. In fact the position of the screws make that impossible - as far as I can see.
Never thought of this, thanks! Of course do this only if I’m sure the semiconductor is faulty or else I’ll snip off a good one n can’t test whether it’s ok or not
Do not think the amplifier runs at mains, likely around 70V rails, with one power transformer doing the input and the other 2 the output sockets, each separate.
just for general info, i just checked it º.º kapton tape, heat pass thru,used in the old days 0.1 W/mK better than notinng... silicone pads, used today 1.6 W/mK so, this is 16 times BETTER
You have to account for the thickness though. If the silicone pads are more than 16 times thicker than the Kapton tape, higher thermal conductivity won’t help.
@@northernlightandsoundyup but they probably used it for isolation and was better compared to using plastic sheets. Most amps I've open manufactured pre 2000's used generic plastic between transistor and heatsink.
The transformers and case are using the house ground, which should definitely be kept separate from the filters and controllers responsible for converting the output into a pure sine wave. That isolation layer is essential to separate the input from the now filtered and modulated output. I would imagine it helps reduce distortion, lower noise in the power, and then help improve the signal-to-noise ratio for both the electricity and the analog side of the audio gear it powers. Great work, wonderful video. Thanks.
extra power consumption for the audio rig. Neat. Also we must not forget the power cables that goes with this - probably cost £1000 per meter. Simply put: This is like pouring melted butter on becon before u serve it. Interesting video tho. :)
I'd have put a couple of internal Wago connectors in it to jumper the input to the output, nicked the magnetics for my windowsill collection, and stuck a housebrick in it to make up for the wieght loss. What kind of mutant would take a rotational machine generated sine and then use an approximated copy of it "for audiophile purposes"? Really - If your amp can't deal with the odd powerline glitch, bin the sodding thing. (Deep breath) - Nice repair.
@@normanbottand then you hear it, and realise, in some ways, it's the best sound you've ever heard. Oh, and way cheaper than some systems I've also heard.
Hi, did the transistors actually use Kapton tape to transfer heat from the transistors to the heatsink? Because if it was used it might be the cause of the origional failure, Kapton tape does not have very good thermal conductivity. Btw I think the screws need to have a fine coat of snake oil to maintain the sonic properties of the power supply.
@@RetroTuna nah you HAVE to replace all the capacitors with space-qualified, anti beta radiation ones, and they have a gold foil / kapton dielectric layer between their vaiorus hiss and click sonic-proofing layers, thanks for the tip I just realised I can use Kapton tape for picture framing as it wont melt in Thailand :-) (PS we got plenty of snakes here)
@@ebaystars Glad you can put a time and date to the last charge cycle but when working as a psu repair engineer i saw lots of open circuit bleed resistors across the mains capacitors... 😁 If you do the math a perfect capacitor will never discharge so i guess its all down to leakage... 🤔
@@GeoffDavis1974 Im old enough to remember CRTS in TVs with HUGE voltages stored on the tubes flyback pin!! Did that thing actually have high voltages over it was it switched mode unit I didnt see a circuit ? looked linear in the main?
The only thing that makes your audio sound better than the loud (unnecessary) fan on the magical AC generator, is when all that pretty AC current enters your amp and almost instantly gets chopped up into DC via a bridge rectifier. Oh well, it was pretty well it lasted until the bridge rectifier destroyed your beautiful artwork AC snake oil. If audiophiles spent a little time learning the basics of electronics, they wouldn't spend a dime on useless snake oil products. If you can't reliably tell the difference in a blind A/B test, than any perceived gains only exist in your head (the placebo effect). Better sound quality comes from spending your money on the few things that actually make a difference. Better amp, preamp, DAC, speakers, room treatment.....
There is a guy here who SWEARS that the kapton tape makes the transistor run hotter, giving the audio a "warm sound" with more "width" and "depth". ROFL My speakers at home are connected to my amp with old leftover ethernet cable, and I don't care.
But what about my depth of field getting bigger? And my warmer punchy round bass? And silky yet transparent mids? And the smooth yet accurate treble? And my stereo field widening? And the fact that my tubes last longer? My $1000/ft speakers cables are at 90• bends for perfect sine wave conductivity. And yes I did make sure my power cables cost at least $5000 and they are most definitely directional. This magic box is a MUST in any serious system. Get with it, bruh!! /s
@@dh-_1011 Haha! I tried one of those directional power cables and it sounded amazing, but it wasn't worth the trouble of having to switch the cable ends around 60 times per/sec, so AC current could flow both ways.
The twin transformers you see are for voltage step up from 115v to 230v for countries that have 230-240v mains. The US models don't have these transformers and the outputs from the board go directly to the power sockets. I have a 230v P600 which is larger version of the P300 and I have it configured to 230v on one bank of outputs and 115v on another bank. For safety I installed NEMA-6 sockets on the 230v side. For when you want to run UK or US equipment without an external stepping transformer. The P300's are in demand by people who have AC motor turntables as you can fine tune the power output frequency.
In finer steps than the 5Hz shown in the video? I work in electronics R&D and have sometimes felt the need of an AC power supply that can be adjusted over the whole 47-63Hz range. I just connect a signal generator to an audio power amp and step-up transformer.
@@connerlabs These power regenerators (P300, P600, P1200) had upgradable software, so it would depend on the software version. Mine can do increments of 1hz, however it cannot go below 50hz, but 63hz is no problem. These units basically are your 3 step setup in one chassis. All the PS power products after this series works differently and you cannot select the frequency.
Another Excellent repair ( and my second viewing of yr videos) I've been avoiding buying ones of these for my Linn systems but maybe I should get one. Also - Re: the Kapton tape, Linn use Mica wafers on the Klout Power amps between the Sanken Trannies and the heat sink block and this is supposed to have improved the sound quality when introduced as a factory enhancement. I'm starting to binge watch you.. instead of getting on with my own projects. Look what you made me do !
It'll warm up your room and increase revenue for the power company. If you believe that Linn know how to design audio circuits then you can safely assume they also know how to design a PSU that'll work just fine over the limits of what the power grid delivers.
@@TerryClarkAccordioncrazy would hope so, but my old dealer in Switzerland still used external Power conditioners, I think from Isotek. I was considering a TORUS TOT MAX for my main Music system and something else for my Home Cinema room once its up and running. But would be good to get a spectrum analyser on the mains first to see how clean or dirty it is. I know a guy who might be able to look at that for me.
@@stephenyoud6125 Any properly designed equipment will work fine on the standard mains. Hifi dealers like to sell more stuff, whether or not it does anything useful. Edited to fix spelling mistake.
Save your money, all equipment changes the AC into DC anyway internally, by rectifying and smoothing, only exception is turntables with a synchronous motor.
Correction to my previous comment. The CV transformer device is called a Volstat, with just two T's not 3. The full trade name is (was?) "Advance Volstat". I have a couple of them stowed away somewhere; one outputs 240 volts, and the other 12 volts. They're quite bulky for their rated output power, but not as bulky as that synthesised sine wave contraption that Mark painstakingly repaired.
This is a wonderful video Mark! I'm 67 and have occasionally done a bit of hands-on electronics and wiring, your videos are interesting in terms of professional technique/tips-to-be-gleaned! BTW, I love the PS Audio regenerators, they make an actual qualitative difference in the sound from my systems.
What a pointless piece of kit, but I suppose someone must buy them. The story of the king’s new clothes comes to mind. As many have said, it’s converted to DC anyway and that’s all the amp see’s. All it really wants is a good low impedance supply which doesn’t sag under load, such as that available from a standard 13Amp socket. All this device can do is raise the impedance. If it were able to lower it, it would be possible to pull more power (for the same voltage) than it’s drawing from the mains, which is clearly impossible. Any conventional power supply only pulls current towards the waveform peaks anyway, which is what leads to the distortion in the first place. If anything, the slightly flat topped waveform will reduce the peak currents in the rectifier and probably prolong its life. The output waveform looks great with a small constant resistive light bulb load. I’d like to see what it does in the real world powering an amp with constantly changing load and phase angle. I’m pretty sure it wouldn’t look any better than the raw mains, not only that, but it would also be constantly ‘on the move’ as well and would also inflict the same wobbly supply on any source equipment. The option of 55Hz is totally bizarre. 55Hz is not used on a properly functioning mains supply anywhere in the world. If you were that worried about the quality of your mains, why on earth would you want a non standard frequency? It seems to me, if you really need one of these, you should have bought audio equipment which was properly designed in the first place.
Audiophiles' brains and wallets don't work that way. They'd strap a tortoise to their amps if someone wrote a convincing article it would help with sound quality.
nah the company should have made Tempest Grade isolation devices (for that ultimate red-black transition) and filters then they would have made zillions from the military
@@chimpana I can think of a number of examples, but I think my favorite so far is audiophiles who use little wooden stands, like tiny 3” telephone poles every 2’ propping up their cables so that their speaker cabling and patch cables (oh, excuse me “interconnects”) do not make contact with their carpet or other flooring, because…that’s…bad. The person I first saw doing that spent 30 min trying to explain to me how much better his system sounded after this modification, and why, in pseudoscientific terms at least, it made such a huge difference to use his wood stands. It’s bizarre and hilarious. It’s woo-woo, almost like a set of supernatural beliefs. Makes me kind of sad, this sort of anti-scientific, non-evidence based approach, but I think the main thing that really drives me nuts about this is that it’s not even necessary because there’s so much great sounding, inexpensive consumer/prosumer and pro-audio gear available! I am a musician, producer/sound designer (and so is my brother), mostly video game music/soundtracks and sound effects, so I obviously enjoy good music, played on a system that is adequate. Audio engineering has long been an apprenticeship-based profession, starting with the “tea boy” role in older studios (or the “roadie” role - in touring and live concert production) so it used to be a bit more difficult to access the knowledge needed to work in our field without some sort of hands-on training…but these days, there are so many ways to learn about the concepts behind sound engineering, so the knowledge is easily available to almost anyone with internet access. I hope more “audiophiles” will realize they don’t even need all this expensive, often absolutely useless and absurd crap to hear their favorite recorded music, faithfully reproduced.
I was shouting at the screen "Check the emitter resistors" Maybe you did off camera but with shorted output transistors something would have to give and it wasn't the fuse.
Exactly that. I was the same way at the screen. I've repaired too many car stereo amps that used those paralleled driver transistors and most of the time when there was a shorted transistor, it's connected emitter resistor was open.
A cheaper way of getting sine wave output and protecting expensive audio and computer equipment, is an APC server grade Uninterruptible Power Supply (UPS). The cheap versions don't have sine wave output, but the better versions do. Mine cost about £350, it comes with a car battery, which lasts 2-4 years before it degrades enough to require replacement. The other advantage, is my PC and audio equipment is protected from surges and sags, and when the power goes out, my PC stays on, until the battery gets low, then it turns itself off.
Generally, UPSes don't regenerate power. They just feed the power input to the output and only switch to the inverter when the mains power disappears. But these devices are good for one thing anyway: fill the bank account of the manufacturer.
@meindertsprang7491 They don't convert AC to DC battery then convert battery DC back to AC output, unless the power goes out. Because that would be an unnecessary drain on the battery. The cheap ones don't put out sine wave output, which the higher grade ones do, by analysing and correcting the mains power, that's why the good ones are more expensive. Most people don't use UPS with their PC, but that results in data loss and data corruption. I like having the ability to keep my computer and sound working, when there's a dip in the power which would cause my PC to turn off, if I didn't have it protected by a UPS. I have my DAC and headphone amp plugged into the UPS, but my amplifier is just plugged into the mains. As I don't mind not being able to play through my speakers when the power goes out. But I do want my PC and internet to stay on. So my router is also plugged into the UPS. This means during power outages, I can still use my landline phone. I think that's well worth the money.
@@davidestabrook5367 I have an APC 1500 Smart UPS on my server and I can assure you that when mains power is present, the UPS does nothing. It just passes mains from input to output, the inverter is not running. So it will not cleanup the mains power in any way.
Seems illogical to take the energy from the outlet, reduce that energy by powering an additional device designed to somehow to improve the performance even though total energy is reduced and possibly restricted, passing through myriad components. I would favor the "less is more" philosophy. Fewer components, less complex circuits, fewer possible points of failure, fewer components to fail. The KISS principle.
@@peterdefrankrijkerFor a normal person maybe, but the average audiophile that cares about how their bloody mains sinewave looks has their head so far up their arse that they won't be able to hear the fan
I used to work in notebook service and kapton tape has been used always to cover nearby elements from heat while soldering and/or electrical insulation, but never this way. Like William J. wrote. "mica plates" is the way to keep stuff cool and isolated.
Perhaps the point of Kapton tape is no need for thermal grease. It will creep into the surface roughness to do the job pretty well. I don’t think I’ve ever seen it used by others. Myself I got this idea some 15 years ago and it has saved many a paper towel from cleaning the grease :) It outperforms mica thermally, that much I know. Maybe not as robust very long-term? So far it’s not failed me once on my projects. Some are under power day-round.
I'd expect that a real audiophile system would dispense with the thermal pads and grease, and instead lap the heat sink and back of the transistors to eliminate any tiny gaps, which would be sure to introduce noise by diverting electrons and making them rub against each other. You'd need to electrically isolate the heatsinks then since they're no longer at ground potential, but surely that'd be worth it. I also used #12 romex electrical wire - solid copper conductors, none of that stranded rubbish where the tiny strands would rub against each other due to the booming bass from my speakers. I had "acoustically stable" mains wiring on my system. Hmm.. maybe I have stumbled into a business in my retirement..
He has many other interesting and satisfying performances, stay tuned. Loved the audiophool bits, interesting and entertaining. I have seen and read of such things and find humor in it, although many are quite vexed.
Good to see o e of Paul's pieces put back into service after years of use. I thought the unit was from the mid 90s when Paul was trying to put back the company on the map after he bought it back (after having sold it). This was one of the first products to really get ps audio going in the direction they are today. They made bigger versions of the the 600 and and 1200 I think for powering various audio pieces. Seen a number of these needing work and it's interesting why these transistors fail and that scorched relay. Only seen a couple of your videos but their fun, inspiring and educational. Just curious if you do any videos on things for beginners like soldering tips, general advice on measuring and tech tips? Thanks from the USA!
Absolutely love the channel for your wayyy in depth repairs,BUT ,cant agree on kapton tape for heat sink insulators, need thermal conductivity along with electrical isolation.
The uTube pushes me around faster than I can "like and comment" . . . many of your views go unrecognized, times like this require me going swimming upstream, you're worth it.
For people that think this is snake oil. It's not, especially for older equipment. I did an experiment and couldn't a signal. The person next to was like, just unplug the cheap LED desk lamp. All the noise was gone instantly. Turns out LEDs lamps don't need any of the strict anti electrical noise filtering that is present in many other devices. Leading to a ton of noise on the electrical grid
I wired my shop with a GFCI breaker and installed LED lights in place of the fluorescents that were there before. As soon as I turned on the lights, the breaker would blow. LEDs just don't play well with others.
If you have noise problems like that, its the equipment power supply, you see you do not need a perfect sine when its rectified and smoothed anyway, only exception is the older sync motor style turntables.
@@engjds Maybe but a device like this would resolve it all the same. And having the variable frequency function is actually quite valuable on its own, I have yet to come across a step down tranformer with that functionality. And I am sure you could buy a device like this that has the frequency variation and a variable AC voltage output. Considering that these go for around 400 usd on the second hand market I don't think it is the worst purchase you can make. Though in terms of audio performance I doubt it is going to do much. Your expensive equipment will like you more though, if you have a clean and regulated power source. Could treat it as a large fuse.
I highly recommend that you upgrade & use a PACE SX-100 desoldering tool. It’s second to none & so good that you won’t know yourself. It uses extremely convenient disposable dross cartridges making its maintenance a breeze!
You know who could use that for it's ability to output 60 Hz? TECHMOAN! he could plug the step down transformer into the output and then generate some real 115V/60 Hz.
Hi Mark. I must say that watching your videos makes me envy the way you tackle such a wide variety of devices. You are a true professional. It's great to see you are able to put your hands on all the parts required and your test equipment is so comprehensive. Keep up the good work. Personally I would like to see you tackle one of those horrible little Denon mini reciver/cd players and their ilk.(model numbers escape me at this moment) Kind regards Allan 😃
There is special high conductivity kapton tape, Kapton MT+, that might have been used originally on those mosfets. Still wouldn't use kapton tape for the job if I didn't have to...
Seeing that disc drive on that scope as mr carlson said you can use vintage repair equipment the get remarkably good results. Just one thing add more vintage equipment 😅 cheers
Love the part snooping and replacement, one question - how the heck do you source the replacement parts when they are so old. Heck I have problems with getting parts that are only 5 years old, let alone DIP chips and specialty relays !
Flooding the connections with solder does work, but I've lifted thinner PCB traces doing that. Boo! on me. This looks like a robust power circuit board, so safer to do. Just have to be careful. Nice to find the core problem so quickly, though. (I swear I can smell the flux in every one of these videos, ha ha.)
I'd like to see the waveform of an audio signal output by a good modern audio amp when plugged directly into the wall, and then after being plugged into this. That's what matters, at least in the real world most of us live in. I doubt very much anyone with a $50,000 (or more) system could tell the difference in a blind comparison. I trust that the engineers who design audio equipment have taken into account that the mains power is not a pure sine wave. I suppose it does have some utility as a huge and expensive surge protector.
GOOD equipment won't generate audible noise until the distortion becomes quite high indeed, on the order of 25-35% or so. (ie, square wave input!). Truly proper kit will eat even that and perform within spec. The main issue with square wave and clipped sine wave power is audible harmonics being generated by the magnetics themselves (transformer hum and hiss) and potentially lower capacity of those magnetics due to partial saturation though any reasonable kit should have enough headroom to deal with
I love the blue power light that’s just an incandescent bulb with a blue filter. By 2000 you’d have thought that was well on the way out, but I guess the design is a little older still.
Heij Buddy, I just wonder: You have the most beautiful measuring stuff and still desolder like a cave man? I do way less fiddeling than You but I didn´t want to put up with that anymore so I bought a desolder station, a zd 915. Applied the overvoltage mod in form of a step down converter in place of some load resistors switched in line with the pump and fan- works splendid. The poor fan gets 18 volts, it´s dragged down by the load of the pump to 12 volts. Now with the converter it´s at 12,5 volts all the time and the pump starts up instant. This thing really sucks now and is way quieter as before. A good machine.
Well, disregarding all the snakeoil comments, cuz there's already enough said about that... Beautiful video! I really do enjoy watching You repair all those things
Oh, nevermind, they're held on by a clamp, not individual screws. Disregard that tip then, it only makes sense when the transistors are held by individual screws
Kapton tape is not thermally conductive; rather, it is known for its excellent thermal insulation properties. Made from polyimide film, Kapton tape can withstand high temperatures (up to about 260°C or 500°F) without degrading, making it suitable for applications in electronics, aerospace, and other industries where heat resistance is necessary. While it can tolerate high temperatures, it does not conduct heat well, which is one of the reasons it is often used as an insulating material. Keratherm Red 86/82 thermal pads are the way to go there. This material is a single solution - there is no need to use thermal grease - just place the insulator between the transistor and heatsink. The Keratherm Red material is silicone and fiberglass material impregnated with ceramic that is thermally conductive. In normal use it can match or even exceed the performance of mica and grease. It is ideal for Class-A and Class-AB power amplifier devices and anywhere you need a good thermal interface. This film is especially suitable for highpower applications. It has excellent thermal and electrical properties. Thanks to its good performance, Keratherm Red can be used reliably in densely packed electronic applications. Also available with adhesive coating as 86/82 K.
Audiophile Power Regenerator Repair. Great vid, thanks. Subscribed. The kapton tape will run the transistors slightly hotter, for an accurate warm sound reproduction with a vintage touch. It will make silicon sound like electron valve vacuum tubes. Further optimizations for a vintage HiFi experience include the omission of the gold-plating, most notably at the connection of the sine board. This feature will ensure that this unit's process of becoming of age will closely resemble to how the rest of your vintage equipment will develop with time.
Hi Mark, love the videos, I got a question with this one, do you think a General Electric UPS VH (700,1000,1500,...) can get the same results as the PS Audio?
A bit of silicone tubing cut on an angle makes a lovely slip-on flexible nozzle extension for those solder suckers. You get a nice seal over the iron tip and joint, which makes the vacuum much more effective, and the silicone isn't deformed by the heat of the iron.
I thought my 4% was bad. Some of the products I service only guarantee specs with power lines THD < 1.0%, which in the 90's might have been possible. I can confirm it's an issue as you get insufficient rail voltage to drive 8 ohms. Usually 4 ohms is fine. Get Hakko to sponsor you and send you an FR-301. It's the first desolder gun I didn't hate.
Isn't Kapton tape a good heat insulator .. feels like a very bad idea to me.. i tested it and the thermal conductivity is rubbish.. i feel it was a bad idea before and is a bad idea now.. Great content Mark keep it up. Big fan.
8:05 These MOSFETs are fried for sure. I prefer to cut their leads short ( close to de body ) before desoldering. This way, stresses to the PCB are significantly reduced as the dead MOSFET are desoldered one at a time.
Nice work, but I'm afraid it may an incomplete diagnosis and repair. When those transistors are in parallel those big sandy resistors (0.22 ohm) are used for keeping one transistor from driving more current than the other. When the transistors short, they tend to take out those attached resistors as well and your video did not show you testing those. When those resistors go open then you aren't getting the pair driving, but rather only one transistor. I've seen this a lot in car stereo amplifiers that used multiple transistors in pairs.
I was about to ask, despite the obvious irrelevance of the mains line condition once it's rectified... Wouldn't an UPS do the same thing... Maybe not be able to switch the frequency though.
you can get most of that functionality by using a server UPS , they have pretty decent sine wave generators in them and are often sold cheap because the batteries have gone out of spec but you don't need the batteries.
I really hope you used an audiophile grade fuse there at the end, otherwise it's going to make the high frequencies too harsh and will ruin the dynamic range. Ideally you'd use a ruby coaxial gold nano strand sheath with silver plated caps. They are expensive but really makes a huge difference.
Thank you Louis Rossman for sending me here. I am subscribed and loving that "new youtube channel backlog" feeling.
He’s done mark a of good. Enjoy that backlog
Same! :)
about 1k new subscribers per day, it seems.
good!
Tom Evans Audio is a marketing powerhouse!
@@kiplinght Ya can't fault 'em! 🤣
In the audiophile realm, a measurable difference is rare to behold!
Well, you have a measurable difference at a power input, but what will be the difference on audio output?
I have no such thing as this, no fancy high-end equipment, yet, with no input, I can't hear s**t coming out of my DIY amp with ear right at the speaker. And not that my AC is clean - it's far from that.
Except it will be rectified and smoothed anyway so its a pretty pointless piece of equipment.
Their hq in boulder is worth a trip even for casual audio fans
Ridiculous, Love watching the channel but that piece of equipment is how a fool and his money are quickly separated. 🤦🏻♂️
@@tomkocur
If I'd paid thousands or 10's of thousands (or even "only" several '00) for audio equipment which turned out to have such a shoite power supply that it couldn't cope with normal public power grid electricity I'd be pretty hacked off....
Definitely a better case and overall construction quality than that £25k POS Tom Evans preamp that got you the copyright strike, bit which is now all over UA-cam 😀
Examination passed. You are a certify PS Audio service enngineer now. It is a fantastic job to preserve the factory correct for this service.
I love how happy fixing things makes you
You'd like NorthridgeFix too, he ends each repair with a big grin when something works 😁
Paul will be contacting you to do all the PS Audio servicing in the UK. (Just kidding). Another excellent video.
That solder sucker makes such a satisfying “nom nom nom” sound
Num num num num...nummy.
Its an RS own brand, have a few.
I dunno what it is but I find these videos informative AND relaxing! Always liked cooking shows and repairs! Seeing something go from useless to great! Thanks for the vids and positive attitude!
As someone that's watching these older videos after having watched most of the newer ones, I do find it interesting that, here, Mark is questioning the use of Kapton tape on transistors while in the Kinki amp follow-up video he defended it (with math!) Now I'm only sad that I'm nearly done watching all of Mark's videos. Incredible stuff!
Thought the same thing. Though the kapton tape is still suboptimal due to its low thermal conductivity.
I've always loved that copper-chrome color of the kapton tape roll.
Hello Mark! I just stumbled upon your channel and I instinctively clicked on the subscribe button. Your troubleshooting and subsequent repair of this "smoke and mirrors/snake oil" AC power regenerator (seriously... how silly) was Top Notch. Color me impressed. BTW, Kapton tape used as an insulator is mildly acceptable, depending on the heat transfer coefficient requirement not needing to be moderately fast, however I take issue with this tape having the ability to be in the same league of thermally transmissive mica, Sil-pads, etc. Kapton tape is coated with adhesive on the sticky side (obviously) and the formulation of this glue does not address having any thermally transmissive properties at all. Just because the Kapton tape is a good insulator does not make it a good thermal conductor. In my opinion, using plain old school mica wafers or the newer Sil-pads will provide much faster heat transfer away from the BJTs and the speed at which the heat can be soaked away can be quite critical, when a lot of current passes through the active devices. Just my $0.02 worth of unsolicited concern. Thank you for the video and you did a beautiful job of repairing this "thing". Fred
was that relay powerful enough? it didn't look meaty enough.
I personally have experience with these "things", and know what positive improvements I can demonstrate in terms of noise-reduction and clarity. Have you used one are are you just convinced they are not worth it? If so why, pray tell...
@@vicweast Let's just put it this way, I've never come across an audiophile who has any knowledge of electronics or physics...
@@vicweast If you want to fight, you can check out the Audio Science Review.
Basically, it doesn't make any sense unless your device's circuitry doesn't use DC, but directly AC.
Any normal circuit's DC side should not be affected by AC in any way unless there are major power surge or blackout.
@@mattparker8747A good example is the late Siegfried Linkwitz (of Linkwitz-Riley filter fame) was a dedicated audiophile and an electronics engineer who designed instruments (Spectrum Analyzers etc) at Hewlett Packard for many years.
Hope you fitted an audiophile-grade relay with ion-infused twisted pair armature leads. That fuse needs to have cost at least fifteen quid, too :)
Low oxygen copper in the windings - you can hear the difference.
And make sure your fuse is fitted the right way round (it matters, apparently!).@@ThePaulv12
Of course. Cryo-treated, rhodium plated.
Well good you say that, because I bet he also turned it upside down so all the quantum tunnelling electrons fell out, it will never sound the same.
@@engjds on the plus side it's improved the hyperacoustic tonal embellishments of the workbench no end.
I wonder how many times his mum has to call him, to come in for his tea. Great content, can't stop watching , what a perfectionist , thank you Mark
Nice video. Two bits of advice if I may... 1, put a sacrificial rubber sleeve over the tip of the solder sucker. It will suck better, and you'll degrade the tip with heat much more slowly. Change the sleeve once a week, or as needed. 2, only solder one pin on the power transistors to hold them. As you assemble back into the chassis, reflow that pin and then solder the others. This will remove just about all of the mechanical stress where the leads enter the resin package, which might prevent problems in the future.
Yeah soldering then mounting is putting a bunch of stress on stuff.
Sacrificial rubber sleaves are a bit hard to come by, anyway, tips are cheap.
@engjds When I was regularly using a solder sucker (1970s to 1990s) rubber sleeving was very common in wiring departments (made by Hellerman among others). I guess it's less popular these days.
Going way, way back to the first days of the PC, we would frequently have to give boards with an edge connector the "pink pearl" treatment. That is, using a Pink Prearl Eraser to clean the contacts. Worked wonders 90% of the time.
Agree! That ISA style connector on the PCB side was heavily corroded and as it created the AC waveform, I'd be surprised if it wasn't that which caused the issue in the first place.
To my experienced eyes, this whole thing smacks of having been (badly) repaired before hence the Kapton tape for SIL pad bodge. Kapton tape as SIL Pads, sorry not on my planet! Good video as usual chap, keep it up! A
its ok as the heatsink is on both sides unlike ususally just back of transistors'.
@@Johny666EU I assume that's a joke.
You're right. Kapton tape is not thermally conductive; rather, it is known for its excellent thermal insulation properties. Made from polyimide film, Kapton tape can withstand high temperatures (up to about 260°C or 500°F) without degrading, making it suitable for applications in electronics, aerospace, and other industries where heat resistance is necessary. While it can tolerate high temperatures, it does not conduct heat well, which is one of the reasons it is often used as an insulating material.
Keratherm Red 86/82 thermal pads are the way to go there. This material is a single solution - there is no need to use thermal grease - just place the insulator between the transistor and heatsink. The Keratherm Red material is silicone and fiberglass material impregnated with ceramic that is thermally conductive. In normal use it can match or even exceed the performance of mica and grease. It is ideal for Class-A and Class-AB power amplifier devices and anywhere you need a good thermal interface.
Kapton absolutely is used as a thermal pad. It's not the best performer but it works. Firts time I've seen it was a Cerwin Vega power amplifier. Rather serious heatsinks, forced air cooling, and all TO-3 transistors mounted on kapton insulators. Fischer Elektronik still makes a range of kapton thermal pads.
Its advantage as a thermal pad is that it is very thin, which more than makes up for the better thermal conductivity of a fat silicone pad. We used mica for years, and Kapton works better than that. The only benefit of silicone is that it is gap-filling so it doesn't need the addition of grease to conduct heat effectively.
Another belter Mark..makes my day...more vintage please.
It’s a money converter. It converts your money into PS Audio's money. ⚡️💰
I think there is a much easier fix: just wire the output directly to the input, and the thing will do exactly the same job as before ;)
You put far too much faith in my local power company
NAILED IT !
😂😂😂
No, you are wrong. The "thing" will do a better job than before.....
😀😃😄
true hater in his natural habitat! Says the arm chair audiophile that does nothing but look at what he can’t afford or have.😮
No matter what kind of dodgy AC line power comes in to audio gear, the power supply in the audio equipment will clean it up- nothing bad will reach the speakers. These AC power conditioners do nothing to improve sound quality- everything it might do is down to placebo effect.
I dont know about the kit nor electronics, but could watch Mark repair a bread board, the old style wooden one for the kitchen, :) well done sir!
Way back in the day I dabbled quite a bit in electronics and I would run across a piece of equipment that had heatsinked power transistors. The manufacturers always used mica and heat sink paste.
Another masterclass in debugging and repair, thanks.
Wow that was interesting to see that waveform clipped before you worked your magic on the PS Audio unit. I have never seen capton tape used before in that way and I worked in electronic manufacturing a long time. As you say there must have been a reason for it. Love your videos.
Mica insulators will give a grainy, mineral sound.
The audio characteristic of silicone is too soft and rubbery.
Kapton will produce a clear tight sound with solid bass and treble.
Unfortunately beryllium oxide will cause severe attenuation of high frequencies and make your high end setup sound like a cheap telephone.
Of course diamond is the superior heat transfer material of choice and produces no noticeable coloration, it is the best if you can afford it.
Vacuum tube amplifiers do not require heat transfer pads. That is one of the reasons they have a superior sound
@@gordonwelcher9598 Spoken like a true audiophile.....Cough!
🤣
@@peterallen8413 At low frequencies the heat is produced in waves. Inappropriate transient properties of the heat transfer material will cause the bass to be severely distorted due to thermal effects on the output transistor junctions. Nonlinear dielectric loss in the stray capacitance will affect the high frequencies. Tighter clamping will make a noticeable improvement in sound.
@@gordonwelcher9598 I'd love to see a double blind test for that woo woo!
Very impressive extension cord stopper.
1:00 That sinewave shape was like that thirty years ago, so IMHO has little to do with "modern" electronics. Conventional power supplies are just as guilty in taking power at the peak of the sinewave as switched mode power supplies are.
I'm not too worried about the slightly distorted mains sinewave, my audio (and other) devices turn it into a regulated DC supply first anyway.
Its not actually the switched mode bit of the power supply that does that, its the rectifier, which has been used forever. SMPS can inject distortion into the net, just not harmonic distortion. Nowadays, there is more regulation on the distortion a supply is allowed to make, so I would imagine it would only get better, as long as we don't collectively buy unregulated imported electronics, which tend to omit most of the improvements, like power factor correction and EMI filters.
Yes, I get a nice waveform out of a ferroresonant converter, which also has a nice advantage that rectifier diodes run cooler due to the flat topped waveform, and it makes for a really good mains filter as well, surviving a few cycles of drop out with no hassle..
Almost as if audiophile kit is expensive snake oil!
You got it, now preach that to the audiophile nutters with more money then sense, this equipment is up there with silver plated mains cable.
HP 8903A analyser - the queen of my set of instruments.
The cooling fan was an added on mod to combat overheating on these power plants. They usually ran very hot and weren't so reliable, as alot of PS Audio stuff was. The new newer power transistors they used were less reliable than the MJ1302/3281. I highly recommend a desolder station on these older double sided boards. Its easy to lift or damage traces on them with the "heat and pull" method.
I'm glad I found this channel. Delightful circuit repair ASMR with such calm and authoritative commentary; it's so relaxing and I just might learn enough to be able to repair my Arcam Alpha 9 integrated amp. Win-win!
Tom Evans brought me here 😂😂😂
Introducing us to Mark is probably Tom Evans biggest contribution to electronics to be fair😅
Can't beat a bit of a smile with Young Marko!! Great Stuff!
I wish you were my neighbour. Great work!
Hi - easier to remove the transistor if you snip the pins first. You can then remove the pins one at a time without needing to overheat (and possibly lift) the pads.
I'd also be worrying about clearances to the case around the capton tape. Presumably those power devices are at mains voltage - pretty sure there isn't 5mm of clearance there. In fact the position of the screws make that impossible - as far as I can see.
Never thought of this, thanks! Of course do this only if I’m sure the semiconductor is faulty or else I’ll snip off a good one n can’t test whether it’s ok or not
Do not think the amplifier runs at mains, likely around 70V rails, with one power transformer doing the input and the other 2 the output sockets, each separate.
Don't trust audio engineers to get normal electrical safety standards correct 🤣
@@ivolol How dare you!! I'm shocked, shocked!! (Apologies to Claude Rains).
⚡⚡😂
just for general info, i just checked it º.º
kapton tape, heat pass thru,used in the old days 0.1 W/mK better than notinng...
silicone pads, used today 1.6 W/mK so, this is 16 times BETTER
You have to account for the thickness though. If the silicone pads are more than 16 times thicker than the Kapton tape, higher thermal conductivity won’t help.
@@northernlightandsoundyup but they probably used it for isolation and was better compared to using plastic sheets. Most amps I've open manufactured pre 2000's used generic plastic between transistor and heatsink.
They used mica in the old days, not kapton...
I doubt these get that hot in the first place.
The transformers and case are using the house ground, which should definitely be kept separate from the filters and controllers responsible for converting the output into a pure sine wave. That isolation layer is essential to separate the input from the now filtered and modulated output. I would imagine it helps reduce distortion, lower noise in the power, and then help improve the signal-to-noise ratio for both the electricity and the analog side of the audio gear it powers. Great work, wonderful video. Thanks.
You don't think it's because the transistor tab isn't at ground potential?
extra power consumption for the audio rig. Neat. Also we must not forget the power cables that goes with this - probably cost £1000 per meter.
Simply put: This is like pouring melted butter on becon before u serve it. Interesting video tho. :)
I must be a nerd as i find these videos informative and fascinating. Thanks again
I'd have put a couple of internal Wago connectors in it to jumper the input to the output, nicked the magnetics for my windowsill collection, and stuck a housebrick in it to make up for the wieght loss.
What kind of mutant would take a rotational machine generated sine and then use an approximated copy of it "for audiophile purposes"?
Really - If your amp can't deal with the odd powerline glitch, bin the sodding thing.
(Deep breath) - Nice repair.
That's generally the opinion of Amir from Audio Science Review. And mine too. PS Audio stuff is vastly over priced .
@@normanbottand then you hear it, and realise, in some ways, it's the best sound you've ever heard. Oh, and way cheaper than some systems I've also heard.
Nice work. If Paul McGowan is watching he'll be offering you a re-location to Colorado!
Hi, did the transistors actually use Kapton tape to transfer heat from the transistors to the heatsink? Because if it was used it might be the cause of the origional failure, Kapton tape does not have very good thermal conductivity.
Btw I think the screws need to have a fine coat of snake oil to maintain the sonic properties of the power supply.
exactly what I thought!
i was type typing the same thing when i seen your post super odd.
@@RetroTuna nah you HAVE to replace all the capacitors with space-qualified, anti beta radiation ones, and they have a gold foil / kapton dielectric layer between their vaiorus hiss and click sonic-proofing layers, thanks for the tip I just realised I can use Kapton tape for picture framing as it wont melt in Thailand :-) (PS we got plenty of snakes here)
I think someone was in this before
The snake oil only comes with NEW gear, it's factory installed. Once opened the magic is gone.
DUDE!! just found your channel the other day and I am really enjoying your videos!! Thanks for taking the time to make these :)
Why did I only now find this channel? Love it, subscribed!
You are quite talented. Grind a notch in the tube of your solder sucker for the iron tip to fit in and it will work better
Notes: don't trust capaitors to discharge themselves. Cut legs from dead components to aid removal. Awesome video bud... 👌😎👍
after being off for 20 years ?
@@ebaystars Glad you can put a time and date to the last charge cycle but when working as a psu repair engineer i saw lots of open circuit bleed resistors across the mains capacitors... 😁 If you do the math a perfect capacitor will never discharge so i guess its all down to leakage... 🤔
@@GeoffDavis1974 Im old enough to remember CRTS in TVs with HUGE voltages stored on the tubes flyback pin!! Did that thing actually have high voltages over it was it switched mode unit I didnt see a circuit ? looked linear in the main?
@@ebaystarsme too, i used to repair those also. the charge is in the tube and the tube has capacitance. Same deal...
Them big caps were not mains level, just high capacitence.
The only thing that makes your audio sound better than the loud (unnecessary) fan on the magical AC generator, is when all that pretty AC current enters your amp and almost instantly gets chopped up into DC via a bridge rectifier. Oh well, it was pretty well it lasted until the bridge rectifier destroyed your beautiful artwork AC snake oil. If audiophiles spent a little time learning the basics of electronics, they wouldn't spend a dime on useless snake oil products. If you can't reliably tell the difference in a blind A/B test, than any perceived gains only exist in your head (the placebo effect). Better sound quality comes from spending your money on the few things that actually make a difference. Better amp, preamp, DAC, speakers, room treatment.....
There is a guy here who SWEARS that the kapton tape makes the transistor run hotter, giving the audio a "warm sound" with more "width" and "depth".
ROFL
My speakers at home are connected to my amp with old leftover ethernet cable, and I don't care.
Yes, a double blind test is the true measure of whether it makes a difference.
But what about my depth of field getting bigger? And my warmer punchy round bass? And silky yet transparent mids? And the smooth yet accurate treble? And my stereo field widening? And the fact that my tubes last longer? My $1000/ft speakers cables are at 90• bends for perfect sine wave conductivity. And yes I did make sure my power cables cost at least $5000 and they are most definitely directional. This magic box is a MUST in any serious system. Get with it, bruh!! /s
@@dh-_1011 Haha! I tried one of those directional power cables and it sounded amazing, but it wasn't worth the trouble of having to switch the cable ends around 60 times per/sec, so AC current could flow both ways.
@@gordthor5351 It’s a labour of love, it’s all about tOaN!!!!!!!!
I use a CVT (Constant Voltage Transformer) to do this job. It works very well and is a passive device. CVTs are expensive as well.
I bought one of those PS Audio Power regenerator used,and I use it as a boat anchor.
The twin transformers you see are for voltage step up from 115v to 230v for countries that have 230-240v mains. The US models don't have these transformers and the outputs from the board go directly to the power sockets.
I have a 230v P600 which is larger version of the P300 and I have it configured to 230v on one bank of outputs and 115v on another bank. For safety I installed NEMA-6 sockets on the 230v side. For when you want to run UK or US equipment without an external stepping transformer.
The P300's are in demand by people who have AC motor turntables as you can fine tune the power output frequency.
In finer steps than the 5Hz shown in the video? I work in electronics R&D and have sometimes felt the need of an AC power supply that can be adjusted over the whole 47-63Hz range. I just connect a signal generator to an audio power amp and step-up transformer.
@@connerlabs These power regenerators (P300, P600, P1200) had upgradable software, so it would depend on the software version. Mine can do increments of 1hz, however it cannot go below 50hz, but 63hz is no problem. These units basically are your 3 step setup in one chassis. All the PS power products after this series works differently and you cannot select the frequency.
Another Excellent repair ( and my second viewing of yr videos) I've been avoiding buying ones of these for my Linn systems but maybe I should get one. Also - Re: the Kapton tape, Linn use Mica wafers on the Klout Power amps between the Sanken Trannies and the heat sink block and this is supposed to have improved the sound quality when introduced as a factory enhancement. I'm starting to binge watch you.. instead of getting on with my own projects. Look what you made me do !
They're great if you want to waste a lot of money and help Paul buy another Tesla.
It'll warm up your room and increase revenue for the power company. If you believe that Linn know how to design audio circuits then you can safely assume they also know how to design a PSU that'll work just fine over the limits of what the power grid delivers.
@@TerryClarkAccordioncrazy would hope so, but my old dealer in Switzerland still used external Power conditioners, I think from Isotek. I was considering a TORUS TOT MAX for my main Music system and something else for my Home Cinema room once its up and running. But would be good to get a spectrum analyser on the mains first to see how clean or dirty it is. I know a guy who might be able to look at that for me.
@@stephenyoud6125 Any properly designed equipment will work fine on the standard mains. Hifi dealers like to sell more stuff, whether or not it does anything useful. Edited to fix spelling mistake.
Save your money, all equipment changes the AC into DC anyway internally, by rectifying and smoothing, only exception is turntables with a synchronous motor.
Correction to my previous comment. The CV transformer device is called a Volstat, with just two T's not 3. The full trade name is (was?) "Advance Volstat". I have a couple of them stowed away somewhere; one outputs 240 volts, and the other 12 volts. They're quite bulky for their rated output power, but not as bulky as that synthesised sine wave contraption that Mark painstakingly repaired.
This is a wonderful video Mark! I'm 67 and have occasionally done a bit of hands-on electronics and wiring, your videos are interesting in terms of professional technique/tips-to-be-gleaned! BTW, I love the PS Audio regenerators, they make an actual qualitative difference in the sound from my systems.
Nope - Please review ua-cam.com/video/jeirY9tC_NU/v-deo.html HTH
What a pointless piece of kit, but I suppose someone must buy them. The story of the king’s new clothes comes to mind. As many have said, it’s converted to DC anyway and that’s all the amp see’s. All it really wants is a good low impedance supply which doesn’t sag under load, such as that available from a standard 13Amp socket. All this device can do is raise the impedance. If it were able to lower it, it would be possible to pull more power (for the same voltage) than it’s drawing from the mains, which is clearly impossible.
Any conventional power supply only pulls current towards the waveform peaks anyway, which is what leads to the distortion in the first place. If anything, the slightly flat topped waveform will reduce the peak currents in the rectifier and probably prolong its life.
The output waveform looks great with a small constant resistive light bulb load. I’d like to see what it does in the real world powering an amp with constantly changing load and phase angle. I’m pretty sure it wouldn’t look any better than the raw mains, not only that, but it would also be constantly ‘on the move’ as well and would also inflict the same wobbly supply on any source equipment.
The option of 55Hz is totally bizarre. 55Hz is not used on a properly functioning mains supply anywhere in the world. If you were that worried about the quality of your mains, why on earth would you want a non standard frequency?
It seems to me, if you really need one of these, you should have bought audio equipment which was properly designed in the first place.
exactly this ^^
Audiophiles' brains and wallets don't work that way. They'd strap a tortoise to their amps if someone wrote a convincing article it would help with sound quality.
@@chimpana I have a giraffe on mine, I read somewhere it improves the high end.
nah the company should have made Tempest Grade isolation devices (for that ultimate red-black transition) and filters then they would have made zillions from the military
@@chimpana I can think of a number of examples, but I think my favorite so far is audiophiles who use little wooden stands, like tiny 3” telephone poles every 2’ propping up their cables so that their speaker cabling and patch cables (oh, excuse me “interconnects”) do not make contact with their carpet or other flooring, because…that’s…bad.
The person I first saw doing that spent 30 min trying to explain to me how much better his system sounded after this modification, and why, in pseudoscientific terms at least, it made such a huge difference to use his wood stands. It’s bizarre and hilarious. It’s woo-woo, almost like a set of supernatural beliefs. Makes me kind of sad, this sort of anti-scientific, non-evidence based approach, but I think the main thing that really drives me nuts about this is that it’s not even necessary because there’s so much great sounding, inexpensive consumer/prosumer and pro-audio gear available!
I am a musician, producer/sound designer (and so is my brother), mostly video game music/soundtracks and sound effects, so I obviously enjoy good music, played on a system that is adequate. Audio engineering has long been an apprenticeship-based profession, starting with the “tea boy” role in older studios (or the “roadie” role - in touring and live concert production) so it used to be a bit more difficult to access the knowledge needed to work in our field without some sort of hands-on training…but these days, there are so many ways to learn about the concepts behind sound engineering, so the knowledge is easily available to almost anyone with internet access. I hope more “audiophiles” will realize they don’t even need all this expensive, often absolutely useless and absurd crap to hear their favorite recorded music, faithfully reproduced.
that thumbprint will make this ps a collectors item when Mark hits the bigtime.
I was hoping he would have wiped it clean.
I was shouting at the screen "Check the emitter resistors" Maybe you did off camera but with shorted output transistors something would have to give and it wasn't the fuse.
Exactly that. I was the same way at the screen. I've repaired too many car stereo amps that used those paralleled driver transistors and most of the time when there was a shorted transistor, it's connected emitter resistor was open.
Basically a UPS (sans batteries) with an "audiophile" price?
A cheaper way of getting sine wave output and protecting expensive audio and computer equipment, is an APC server grade Uninterruptible Power Supply (UPS). The cheap versions don't have sine wave output, but the better versions do.
Mine cost about £350, it comes with a car battery, which lasts 2-4 years before it degrades enough to require replacement.
The other advantage, is my PC and audio equipment is protected from surges and sags, and when the power goes out, my PC stays on, until the battery gets low, then it turns itself off.
Generally, UPSes don't regenerate power. They just feed the power input to the output and only switch to the inverter when the mains power disappears. But these devices are good for one thing anyway: fill the bank account of the manufacturer.
@meindertsprang7491 They don't convert AC to DC battery then convert battery DC back to AC output, unless the power goes out. Because that would be an unnecessary drain on the battery.
The cheap ones don't put out sine wave output, which the higher grade ones do, by analysing and correcting the mains power, that's why the good ones are more expensive.
Most people don't use UPS with their PC, but that results in data loss and data corruption. I like having the ability to keep my computer and sound working, when there's a dip in the power which would cause my PC to turn off, if I didn't have it protected by a UPS.
I have my DAC and headphone amp plugged into the UPS, but my amplifier is just plugged into the mains. As I don't mind not being able to play through my speakers when the power goes out. But I do want my PC and internet to stay on. So my router is also plugged into the UPS. This means during power outages, I can still use my landline phone. I think that's well worth the money.
@@davidestabrook5367 I have an APC 1500 Smart UPS on my server and I can assure you that when mains power is present, the UPS does nothing. It just passes mains from input to output, the inverter is not running. So it will not cleanup the mains power in any way.
What model?
@@minime9400 I'm using an APC Smart-UPS 750VA, the model is SMT750i
I like your method of adding solder and heat from the back to avoid pulling pads off on the backside.
i agree!
Really enjoyed that this morning..unsure how audible of a improvement it would be but interesting all the same.👍
Seems illogical to take the energy from the outlet, reduce that energy by powering an additional device designed to somehow to improve the performance even though total energy is reduced and possibly restricted, passing through myriad components.
I would favor the "less is more" philosophy. Fewer components, less complex circuits, fewer possible points of failure, fewer components to fail. The KISS principle.
Wouldn’t the sound of a cooling fan in the room negate the whole audiophile listening experience?
@@peterdefrankrijkerFor a normal person maybe, but the average audiophile that cares about how their bloody mains sinewave looks has their head so far up their arse that they won't be able to hear the fan
I used to work in notebook service and kapton tape has been used always to cover nearby elements from heat while soldering and/or electrical insulation, but never this way. Like William J. wrote. "mica plates" is the way to keep stuff cool and isolated.
Very Nice I'm sure Paul McGowan would be impressed.
I don’t think so I believe he likes to work on his own equipment he’d want any of his secrets getting out into the world.
Fabulous work Mark. Thanks for the vid.
Imagine him and Mr. Carlson having a conversation.
That would be a long video :D Love Carlson's lab :)
FINALLY!
A PS-AUDIO BS!
Thanks YT algo.
The NOISE-HARVESTER for next!
Perhaps the point of Kapton tape is no need for thermal grease. It will creep into the surface roughness to do the job pretty well. I don’t think I’ve ever seen it used by others. Myself I got this idea some 15 years ago and it has saved many a paper towel from cleaning the grease :)
It outperforms mica thermally, that much I know. Maybe not as robust very long-term? So far it’s not failed me once on my projects. Some are under power day-round.
no
I'd expect that a real audiophile system would dispense with the thermal pads and grease, and instead lap the heat sink and back of the transistors to eliminate any tiny gaps, which would be sure to introduce noise by diverting electrons and making them rub against each other. You'd need to electrically isolate the heatsinks then since they're no longer at ground potential, but surely that'd be worth it.
I also used #12 romex electrical wire - solid copper conductors, none of that stranded rubbish where the tiny strands would rub against each other due to the booming bass from my speakers. I had "acoustically stable" mains wiring on my system.
Hmm.. maybe I have stumbled into a business in my retirement..
I can't believe I watched a man stick Kapton tape on transistors for five minutes... lol. Cool video. New subscriber.
He has many other interesting and satisfying performances, stay tuned. Loved the audiophool bits, interesting and entertaining. I have seen and read of such things and find humor in it, although many are quite vexed.
Good to see o e of Paul's pieces put back into service after years of use. I thought the unit was from the mid 90s when Paul was trying to put back the company on the map after he bought it back (after having sold it). This was one of the first products to really get ps audio going in the direction they are today. They made bigger versions of the the 600 and and 1200 I think for powering various audio pieces. Seen a number of these needing work and it's interesting why these transistors fail and that scorched relay. Only seen a couple of your videos but their fun, inspiring and educational. Just curious if you do any videos on things for beginners like soldering tips, general advice on measuring and tech tips? Thanks from the USA!
PS Audio made money buy scamming uneducated old "idiots".
It is nice to see I am a fan of ps from New Zealand
Absolutely love the channel for your wayyy in depth repairs,BUT ,cant agree on kapton tape for heat sink insulators, need thermal conductivity along with electrical isolation.
The uTube pushes me around faster than I can "like and comment" . . . many of your views go unrecognized, times like this require me going swimming upstream, you're worth it.
For people that think this is snake oil. It's not, especially for older equipment.
I did an experiment and couldn't a signal. The person next to was like, just unplug the cheap LED desk lamp.
All the noise was gone instantly. Turns out LEDs lamps don't need any of the strict anti electrical noise filtering that is present in many other devices.
Leading to a ton of noise on the electrical grid
I wired my shop with a GFCI breaker and installed LED lights in place of the fluorescents that were there before. As soon as I turned on the lights, the breaker would blow. LEDs just don't play well with others.
If you have noise problems like that, its the equipment power supply, you see you do not need a perfect sine when its rectified and smoothed anyway, only exception is the older sync motor style turntables.
@@engjds Maybe but a device like this would resolve it all the same. And having the variable frequency function is actually quite valuable on its own, I have yet to come across a step down tranformer with that functionality. And I am sure you could buy a device like this that has the frequency variation and a variable AC voltage output. Considering that these go for around 400 usd on the second hand market I don't think it is the worst purchase you can make. Though in terms of audio performance I doubt it is going to do much. Your expensive equipment will like you more though, if you have a clean and regulated power source. Could treat it as a large fuse.
I highly recommend that you upgrade & use a PACE SX-100 desoldering tool. It’s second to none & so good that you won’t know yourself. It uses extremely convenient disposable dross cartridges making its maintenance a breeze!
Second to none, after the Metcal desoldering tool. Of course not many people can afford Metcal prices, and it requires a seperate compressor.
You know who could use that for it's ability to output 60 Hz? TECHMOAN! he could plug the step down transformer into the output and then generate some real 115V/60 Hz.
Good thinking, this would be ideal for Mat. Didn't occur to me when I was watching the repair.
Who?
@@ShainAndrews Enter "techmoan" into the youtube search field. Usually the first entry gets you to the channel.
@@ShainAndrews www.youtube.com/@Techmoan/videos
Hi Mark. I must say that watching your videos makes me envy the way you tackle such a wide variety of devices. You are a true professional. It's great to see you are able to put your hands on all the parts required and your test equipment is so comprehensive. Keep up the good work. Personally I would like to see you tackle one of those horrible little Denon mini reciver/cd players and their ilk.(model numbers escape me at this moment)
Kind regards Allan 😃
There is special high conductivity kapton tape, Kapton MT+, that might have been used originally on those mosfets. Still wouldn't use kapton tape for the job if I didn't have to...
I don't know but after all, it will be converted to DC anyways. But if your TT is using an AC motor, then that would work great 👍
"I'm not electroboom" is the best part of this video🤣
He is just as funny when he gets zapped. He even swears sometimes.
Seeing that disc drive on that scope as mr carlson said you can use vintage repair equipment the get remarkably good results. Just one thing add more vintage equipment 😅 cheers
Well learned something, resolder before desolder! Why do you do the center pins after doing the die pins?
Impeccable work!
Love the part snooping and replacement, one question - how the heck do you source the replacement parts when they are so old. Heck I have problems with getting parts that are only 5 years old, let alone DIP chips and specialty relays !
Get em from Paul Mc Gowan.
Flooding the connections with solder does work, but I've lifted thinner PCB traces doing that. Boo! on me. This looks like a robust power circuit board, so safer to do. Just have to be careful. Nice to find the core problem so quickly, though. (I swear I can smell the flux in every one of these videos, ha ha.)
I wonder if the gaping hole used to house a fan-shaped filter?
I'd like to see the waveform of an audio signal output by a good modern audio amp when plugged directly into the wall, and then after being plugged into this. That's what matters, at least in the real world most of us live in. I doubt very much anyone with a $50,000 (or more) system could tell the difference in a blind comparison. I trust that the engineers who design audio equipment have taken into account that the mains power is not a pure sine wave. I suppose it does have some utility as a huge and expensive surge protector.
This is why people like Sennheiser provide separate psu for their 50 grand plus headphones etc nice clean power plus the old tubes look awesome!!!
GOOD equipment won't generate audible noise until the distortion becomes quite high indeed, on the order of 25-35% or so. (ie, square wave input!). Truly proper kit will eat even that and perform within spec. The main issue with square wave and clipped sine wave power is audible harmonics being generated by the magnetics themselves (transformer hum and hiss) and potentially lower capacity of those magnetics due to partial saturation though any reasonable kit should have enough headroom to deal with
I love the blue power light that’s just an incandescent bulb with a blue filter. By 2000 you’d have thought that was well on the way out, but I guess the design is a little older still.
i love youre channel sir phil collins
Heij Buddy, I just wonder: You have the most beautiful measuring stuff and still desolder like a cave man?
I do way less fiddeling than You but I didn´t want to put up with that anymore so I bought a desolder station, a zd 915. Applied the overvoltage mod in form of a step down converter in place of some load resistors switched in line with the pump and fan- works splendid.
The poor fan gets 18 volts, it´s dragged down by the load of the pump to 12 volts. Now with the converter it´s at 12,5 volts all the time and the pump starts up instant. This thing really sucks now and is way quieter as before. A good machine.
Well, disregarding all the snakeoil comments, cuz there's already enough said about that...
Beautiful video! I really do enjoy watching You repair all those things
Oh, nevermind, they're held on by a clamp, not individual screws. Disregard that tip then, it only makes sense when the transistors are held by individual screws
Kapton tape is not thermally conductive; rather, it is known for its excellent thermal insulation properties. Made from polyimide film, Kapton tape can withstand high temperatures (up to about 260°C or 500°F) without degrading, making it suitable for applications in electronics, aerospace, and other industries where heat resistance is necessary. While it can tolerate high temperatures, it does not conduct heat well, which is one of the reasons it is often used as an insulating material.
Keratherm Red 86/82 thermal pads are the way to go there. This material is a single solution - there is no need to use thermal grease - just place the insulator between the transistor and heatsink. The Keratherm Red material is silicone and fiberglass material impregnated with ceramic that is thermally conductive. In normal use it can match or even exceed the performance of mica and grease. It is ideal for Class-A and Class-AB power amplifier devices and anywhere you need a good thermal interface. This film is especially suitable for highpower applications. It has excellent thermal and electrical properties. Thanks to its good performance, Keratherm Red can be used reliably in densely packed electronic applications. Also available with adhesive coating as 86/82 K.
Audiophile Power Regenerator Repair. Great vid, thanks. Subscribed.
The kapton tape will run the transistors slightly hotter, for an accurate warm sound reproduction with a vintage touch. It will make silicon sound like electron valve vacuum tubes.
Further optimizations for a vintage HiFi experience include the omission of the gold-plating, most notably at the connection of the sine board. This feature will ensure that this unit's process of becoming of age will closely resemble to how the rest of your vintage equipment will develop with time.
🤣
and all that before the conversion to DC! Remarkable.
I always use 2.5 mm cooker cable to run to my speakers to ensure a pure warm sound all the way to the little Tannoy coils
You have a hidden talent for writing articles in audiophile magazines. ;-)
Sometimes it's hard to see if people are joking or not haha. Good job. :D
Hi Mark, love the videos, I got a question with this one, do you think a General Electric UPS VH (700,1000,1500,...) can get the same results as the PS Audio?
How much distortion to the 'pure' sine wave does the bridge in the audio amp add Lol?
A bit of silicone tubing cut on an angle makes a lovely slip-on flexible nozzle extension for those solder suckers. You get a nice seal over the iron tip and joint, which makes the vacuum much more effective, and the silicone isn't deformed by the heat of the iron.
Sounds like a good idea 🙂
I thought my 4% was bad. Some of the products I service only guarantee specs with power lines THD < 1.0%, which in the 90's might have been possible. I can confirm it's an issue as you get insufficient rail voltage to drive 8 ohms. Usually 4 ohms is fine.
Get Hakko to sponsor you and send you an FR-301. It's the first desolder gun I didn't hate.
Isn't Kapton tape a good heat insulator .. feels like a very bad idea to me.. i tested it and the thermal conductivity is rubbish.. i feel it was a bad idea before and is a bad idea now.. Great content Mark keep it up. Big fan.
8:05 These MOSFETs are fried for sure. I prefer to cut their leads short ( close to de body ) before desoldering.
This way, stresses to the PCB are significantly reduced as the dead MOSFET are desoldered one at a time.
Nice work, but I'm afraid it may an incomplete diagnosis and repair. When those transistors are in parallel those big sandy resistors (0.22 ohm) are used for keeping one transistor from driving more current than the other. When the transistors short, they tend to take out those attached resistors as well and your video did not show you testing those. When those resistors go open then you aren't getting the pair driving, but rather only one transistor. I've seen this a lot in car stereo amplifiers that used multiple transistors in pairs.
Only audiophiles would pay twice as much for an online UPS without the batteries.
I was about to ask, despite the obvious irrelevance of the mains line condition once it's rectified... Wouldn't an UPS do the same thing... Maybe not be able to switch the frequency though.
I think he got a deal since it’s used Einstein.😂
you can get most of that functionality by using a server UPS , they have pretty decent sine wave generators in them and are often sold cheap because the batteries have gone out of spec but you don't need the batteries.
That huge thing is only good for 500 watts? I’ve had smaller power inverters that were good for 120Volts 2500 Watts.
I really hope you used an audiophile grade fuse there at the end, otherwise it's going to make the high frequencies too harsh and will ruin the dynamic range. Ideally you'd use a ruby coaxial gold nano strand sheath with silver plated caps. They are expensive but really makes a huge difference.