I have the CA-1010 since i bought it new in 1976 and just had some work done by a 40 year experienced tech . The repair expert commented how well these amps are built and how output wattage is very conservative . The comparable replacement model today is $3100 vs the $475 I paid in 1976. When running at low power levels this amp is running pure class A . I love that we still have some master tech's like you to fix our vintage gear. Thanks for doing this art of repair .
Great amp. 3-4 weeks ago I rescued a CA-810 from being scrapped. Yes, some people are insane and I was glad I was there at the right time and rescued it. It works as it should, but I should restore it and also replace the relay which takes a good while to activate. Need to replace the lamps too. Great video! Greetings from sweden.
This is a superb restoration of an excellent integrated amplifier. In addition to failing LEDs and capacitors, cold or weak solder joints on some of the RCA connectors often cause trouble, as people are tending to use these wonderful amplifiers that came in many different models for over fifty years now! The potentiometers on these amp's, as well as the front panel switches, tend to often become very electrically noisy after all those years, and it's crucial if you repair or replace the 'ganged' Volume Pot's that these are precisely matched. Yamaha amp's are notorious for the way you could set the volume very close to zero, and still get the same signal level and thus sound pressure at both the left and right channels or speakers, something many other amplifiers do very poorly. Noisy pot's are almost always an issue after five decades, whether the amp is used little or lots, and while these can usually be cleaned and made to work again for another year, at some point, the 'snap, crackle, and pop' becomes too annoying, and these must be replaced. It's important to try to find the matching pot's, especially for the Volume Knob, as these are 'ganged' and this requires a special tolerance value so they will behave similarly. The design of the preamp circuit in all Yamaha Natural Sound amplifiers is very precise, and so these amp's usually come with shunts for the unused (usually Phono 2) jacks. If you pick up a used amp, these shunts will probably be missing, and a simple 25-cent part can help keep the amplifier running quietly. There is also a Ground Wire Jack for the turntable, and yet some models might run quieter WITHOUT using this ground connection! As many people are adding turntables and enjoying vinyl, learning about stylus designs, direct-drive vs. belt drive noises, and RIAA Equalization Curves, and yes, even grounding circuit noises all need to be examined. And let's not get started on disc washers and special, 'designer' cables! Anyway, the reason I am posting is with regards to the Yamaha Loudness Function Control: Your demo of the Loudness Control was sufficient and adequate to illustrate how it works, but it would be good to also show the way Yamaha actually intended this to be used: First, with the volume low, you turn the Loudness Knob (the smaller of the two knobs) to FLAT (all the way up), and now you turn up and set the main Volume Knob to approximately the highest volume level that you intend to use, which may be at level 2 or 3 out of 10 for background music, or 5 or 6 out of 10 for moderate listening in a group of three or four friends, or up to 7 or 8 out of 10 for a party! (That's the beauty of these very low Total Harmonic Distortion amplifiers, is that you can actually use 75% to 80% of the range of the volume setting, and with such good design and a high damping ratio, the amplifier will rarely begin clipping, even into a 4-ohm load. Try that on most other amp's; they will often clip terribly once the volume gets beyond about 6 or 7 out of 10 (I'm try to resist saying, "This goes to Eleven!") Set most integrated amp's volume knobs beyond about 60% of the way toward maximum, and it will begin distorting and clipping like mad! Anyway, now that you have your preferred maximum volume set for the current listening session, then set the bass and treble to their preferred settings, which should be as close to zero as the room acoustics allow (the tone defeat settings remove the equalization knobs from the circuit entirely, in order to further reduce distortion and possible noise). Okay, now you are ready to use the Yamaha Loudness function as intended: just crank the Loudness Knob back down to whatever level you prefer, and the lower you turn the Loudness Knob, the more bass and treble boost gets added, essentially to compensate for the way our human ears tend to "roll off" both low and high frequencies as the sound pressure level gets reduced. It really helps to understand the way the designers intended this to be used if, as you alluded to, you show the curves of both the low and high frequency 'boost' that gets added gradually with this Loudness Knob as you LOWER or turn down the Loudness Knob (and not the Volume Knob). Therefore, in summary: you set the peak or maximum desired volume for your current listening session with the Volume Knob, then adjust the equalization (bass and treble) if needed (or use DEFEAT for FLAT response), and from then on, use ONLY the Loudness Knob (the smaller knob) to adjust your volume! In this manner, unlike most amplifiers in which Loudness Compensation is a SWITCH of "All or Nothing," the Variable Yamaha Loudness Knob provides a continuous and "smooth" boost of both low and high frequencies as you reduce the volume via the Loudness Knob! Anyway, that is the way the designers intended their system to be used. - j q t -
Thank you for this video. I've been using a Yamaha CA-710 since about 1977 - 78. Never felt the need to change it. 40 years service and only been to the shop once and still looks brand new! Even the light globes are originals. As soon as COVID is over it will be going in for it's 20 year service and re-cap. Might even spring for a shielded AC cable for it.
I've been working on electronics for decades but I always gain something from watching your videos. Some versions of that old glue can become conductive when they get old. As you can imagine, that can cause all kinds of problems. I had to spend a lot of time scraping off old glue on a piece of gear I was repairing because it was shorting out parts of the circuit and causing parts to fail. Also, I use aquarium grade silicone glue because it does not have any corrosive chemicals that might harm fish. Keep up the good work!
I worked for a Yamaha Service Center in the 70's and 80's. The NEC transistors are not original even if they appear to be. Yamaha always used Toshiba transistors for the outputs. Also, they would never use different types in different channels. Thought I would clear up that thought.
Thanks . Really good video. In 3 days going to pick up this amp (350 km in one way). As the owner sad, he has it for 40+ years, never had any problem. Nobody Touched it inside - what I like. I'm an industrial electrician for more then 25 years, and in this aria, my last project for fun was sansui au 7900, the owner was happy. Hope this video will be very helpful to restore a new toy. Right now I have KEF 104/2 and Tannoy srm 12x with only one amp - Marantz PM 8005. Hope this amp will work well with one of those speakers. (They are realy different :)
I've had a ca 800 since the late 80's. It runs well but due to it's age it'll head into the shop for some work in order for it to keep working for a long time. Thanks for the videos!
Yes, the Yamaha CA-800 has the coveted Class A circuit, with a front panel switch that can dim the lights if you're hooked up to a cheap extension cord with the Christmas Tree lights! Class A is the amplifier equivalent of setting your car's idle speed to be 7500 rpm! Greta Thunberg would probably scream, _"How Dare You?!"_ and _"Blah! - Blah! - Blah!"_ . . . but calm down, child, it's a few hundred watts! I had the Yamaha CA-400, with its truly useful Microphone Mixing, so back in the 70s and 80s, I could record stereo sound and mix spoken dialog (such as when my infant son was learning to read) and make numerous other recordings with stereo music background, and it really makes quite a difference! - j q t -
Those THD #'s are what one can generally expect from that era Yamaha! They were always my favorite equipment! We wouldn't even consider dropping down to Pioneer! The meters were a nice bright even pale creamy white color...no blue whatsoever? And yes, we purchased these new in the mid-late 70's. We chose our equipment by reading the specs! THD & IMD also the frequency response as well as the S/N ratios. If the numbers weren't there, I didn't even want to hear it ! The only problems I can remember were replacing the wheat lamps every now and then, but well worth it for the performance...
I acquired my very own smaller sister amp the Yamaha CA-510 amp brand new on my 15th birthday back in the fall of 1978. I also remember seeing and experiencing the more powerful CA-810 next to my soon to be purchased 510 in the sound room at the local stereo/record store A&B Sound in Victoria Canada a once iconic Canadian music store chain. I loved that amp, when it was in its prime in the late 70's to early 90's. Sadly the old CA-510 finally died in smelly, smoky fashion in the early 2000's. I would love the get the new Yamaha retro CA-inspired A-S1200.
Thanks for the video I just stumbled onto your channel. I've been using a CA-800 in my system pretty consistently for about 30 years. It's a little smaller than the CA-810 and doesn't have meters but it can run in class A.
I've got two Yamaha M60 amplifiers (both are in protect mode) in great condition. If you'd be interested in repairing one for me, I'd be happy to give you the other. I've also got two Advent 350 integrated amp / tuners. I really enjoy and appreciate your videos. Thank you for taking the time to share your knowledge with us. 👍🙂
Great job Tony I restored one of these couple a weeks ago I really like the CA810.I actually got the DC offset lower by closely matching the differential pair for each channel got it down to around 9mv or so. But heck 20mv is no problem really enjoy your videos.
Nice one Tony, good timing as I am about to put a CA2000 on the bench for restoration!! I'll make sure I check those sockets just in case!! Looking forward to the next one.
Any special technique needed when pulling the output transistors out of their TO-3 sockets? Just remove two screws and pull out? Inverse for re-installation?
I have owned a CA 600 since new in 1976. The loudness control is used very differently than you were using it. It is designed to make up for the perceived change in the sound as the volume is reduced. How you use it is to set loudness to FLAT then adjust the amp to as loud as you would ever want to listen. You then make any adjustments to the tone if you want to and from then on, you use the LOUDNESS knob to reduce the LOUDNESS you are listening to, you do not adjust the volume knob agan for normal listening. The LOUDNESS knob then is used the way you would normally use the VOLUME knob.
That's not how we used it. We pretty much always set the tone controls to flat. The only time we used the loudness switch was at lower volume levels. We only used the volume knob. I never heard, nor saw anyone else using the loudness switch like you mentioned?
Great to watch. Have purchased a Pioneer VSX838 bout 6 years ago. It lasted just under 2 years. My old Pioneer SX300 1973 is still going apart from the festoon and stereo lamps. Looking like the best and most reliable are the old'ns. Pioneer SX1050 would be nice, they are about.
I had to change out the pre-main jumper RCA's on my amp due to one being intermittent. I put the heat shrink on the replacement RCA jack before installing it. Thanks for the tip and it might save some frustration in the future. I am using jumper wires with actual RCA plugs, not the solid, bent rod type, though.
Yamaha make fantastic well built pieces of kit, superbly well designed and put together an engineers dream to service and repair, i have owned a number of yamaha items and i have to say i am a massive fan of their gear, i have to say on a personal note i think their gear is very good value for money great specs and performance
I just bought a ca-610 off ebay, I wanted an 810 but they are tough to find. Hopefully the 610 will be powerful enough. Update, received it today and all I can say is wow, the photos do not do it justice.
I have a CA-810. Today I found my left VU meter needle stays at the max to the furthest right when power is on. I had tried to turn on/off, and unplugged the machine but no use. Sound come out from both left and right without problem. So, is the meter “dead”? Anything I can to to restore it? Many thanks to any advice.
A trick for the LED lighting. Use fine (+1000) sandpaper on the outer surface of the LED. This diffuses the LED to a bulb like glow, which is a very even one.
Very nice! Whats your opinion on replacing filter caps? Historically, I always replace but trying to find anything in the 12000uf to 18000uf 40mm casing is about impossible. Digi, Mouser, all 0 stock. I'm to the point of salvaging early 2000's amps for filter caps.
I recently fully re-capped a CA-810 with Audio grade Nichicon caps including filter caps as well, but I still can hear light Humming when idle, it's not increasing even with full volume at idle, stays in same level. also it goes away when de-coupled pre-amp and power amp. mid point show 1.3mv and idle current is healthy as 20mv. looking for a help.
The sub board with the switch is often damaged. Based on its location. Inspect the traces and joints. Some bypass the board entirely. Jumper wire it and see if it goes away as a test.
I have the same problem with a HK 680. I replaced the large capacitors but it just sounds better LOL, the humming doesn't stop. Initially I thought that the humming derives from the transformer but they are only the fins of dissipator on which the final transistors that vibrates. The bias currents in mine are perfectly set at +-21v, I noticed that decreasing the bias value also decreases the vibration. It could be the pre-stage transistors that should be changed (all of them). In the end I think it's just the flaps that are too large and poorly designed.
Just proved my SU-V3 still works with the help of this video! First amp my dad bought me as a kid. So glad to know it still works! Need to clean it up properly though - I still have to wiggle the input selector to get both channels to work.. But not sure on the best method / what to use.. Any advice?
Hello sir, i understand it’s been 5years ago. Could you tell me ….i have 2 resistors on my PCB board for the lights. Did you replaced two of them or just one for 8.2k..? To install led bulbs. Thank you!
This is so cool I have one of these i got at an estate sale and we ran it a bit but a cap went out or something so its been sitting. Hopefully i can check this out and get it running!
Holy shit... My room-mate/best friend had that exact amp ! That was ~1982. We had some stage type Cerwin Vegas, a wood/glass Oracle turntable and I think it was a Teac dual cassette deck. Picture a lot of "brand new" Van Halen, ZZ Top and such. With a good dose of Pink Floyd, Zepplin, Stones... good days. :)
nigel mahabir Hi Nigel, I have CA-1000 model. It works perfectly, but I would like to restore it to even more perfection, which for this price is very execrable. Where are you located? I’m from Toronto, Canada. Please return to me. Thanks.
thanks for posting! .. Yamaha's don't get seen much .. my experience has been they have high negative feedback, leaving them cold and sterile ..they also seem to be lacking in Bass
How much did you charge for this restoration and what is your turn around time if I send you the exact same amp. If I had to guess off watching your video my speaker channels are bad. Great video I have none of your equipment or any skill set in this area of electronics. I've already been ripped off for $180 from a local shop that did nothing other then turn it on and gave it back. Also, brand name and dealers that sell that cleaning pen you used. Thanks
Thanks so much Tony for your teachings this art of radio & music making machines of the good old days, I have a Aragon 4004 mk2 amp that pops & hums I bought new maybe 20 yrs ago & can't seem to find anyone I trust to work on my baby I live in LA aria do you know a good repair technician in L.A . Or close to me in California were I can get this jewel fixed thanks so much Tom...Joe Logston
If the signal transistor leads are tarnished it can migrate into the body of the transistor, cause noise, low gain, leakage etc. 40 year repair tech. Examples 2SD458, 2SC1345.
If the main filter caps ck’ed good and you didn’t replace them, did you check any of the other caps you replaced to see if they ck’ed good? Or was it just easier to replace the small caps then try and source and replace the big ones?
Hi! Thanks for posting this. I have the CA-2000 that looks very much like this. The power switch/knob got bent and half broken during shipping to me. I need to take the face plate off to get to the switch/knob to fix it but am not sure how. To get all the obstructive knobs off the face plate, do I just need to pull them off the shafts? I've tried but they're really tight so I'm afraid that I might break something if I pull too hard. Do I also just need to pull the balance ring out and it will come off the shaft? Please help and show me how! Thanks!
I've found that on some audio equipment the knobs will sometimes have "set screws". They're usually a micro flat head or phillips screwdriver or possibly an Allen wrench. Hope this helps 🙏 👍🙂
With fan cooling base I used to drive 2x 200 watt theatre bins for the town discos and parties ('76) Later used last summer driving outdoor sound for village event- such good amplifiers...
I have a Technics SA-410 that comes on and clicks but no sound. Where can I send it for repair? It made a pop when it quit working. So I know it fried something.
But when you were talking about the filter caps it is better to have two bridge rectifiers filtered in between each other with a small capacitor before the filter caps this is better than replacing the original capacitors for bigger ones. Do you ever do this as an upgrade and maybe using 4 to split the channels. That relay are the contacts silver you won't silver contacts. Why did you swap out the power transistors what benefit are these new ones you put in?
Output transistors don’t really need to be matched. As long as the betas are at least 60, it’s fine. Beta droop at high current is a bigger issue. The bias circuit sets the idle current. 20mV across 0.47 ohm is a 42mA. About what I’d expect. And if there’s an adjustment on the input stage, you’ll be able to zero the output. Input transistors ought to be matched.
enjoyed the vid, i am old school so i like old stuff too. would you be interested in restoring an old nakamichi 550 cassette deck? i've had it a long time and would like to get it back in shape. it's in pretty good condition, should just need cleaning and calibration. it's a great old deck, but like me, it's getting along in years and needs a checkup.
One thing I don't understand. Given the wide bandwidth, and the fact you can compose square waves from a bunch of sine waves, I am suprised the square waves are not a bit better. I know there's a limit to slew rate and such. I play some synths, and square waves generally sound good in spite of the fact the waves are not perfect, so maybe it doesn't matter that much.
Thanks for the comment! There's always a trade-off when designing these circuits. Negative feedback will affect the slew rate of an amp, even if you use transistors with high transition frequency and careful circuit design. There's always been debate over feedback vs low/no feedback. There are pros and cons to both. At the end of the day, what really matters is how the amplifier sounds to you and how it works with your speakers, not how it looks on a piece of test equipment. I really like the sound of these Yamaha amps, but I also like the sound of the Sansui AU-X1 that has very little feedback in the design. They both sound very different when connected to the same speakers and it comes down to personal preference. Hope that helps. Cheers!
Thanks for your great videos, a big fan of your channel. I have the same amplifier and want to line the phono switch up with the markings. Could you please tell me what type of locking screw tool and size to use please. We use metric so I'm not sure if I can use. Appreciate any advice on removal and anything else I may need to be made aware of, thankyou.
Hello, nice video, thanks! I recently bought this machine type and I use it for listening to analog sound from vinyl and also CDs. Connected to a pair of floorstands, the sound is brilliant! Machine runs fine, yet there is a small inconvenient: I hear radio interferences in both speakers, the sound is almost imperceptible but mostly at late hours when the room is very silent it gets annoying. Radio sound is equal in level on both channels and it is not influenced by the master volume level. It stops only when no RCA sources are connected to the back inputs (any input!). I have to say that I use very good interconnect shielded cables, that I just bought in order to clear this lead, so I presume that the issue comes from somewhere in the machine. Does this ring any bell? I would like to get it sorted out. Thank you! (I am mechanical engineer, I do not performs electronics repairs myself, but I have quite enough understanding of how things works, I am an old enthusiast of audio systems for home music listening).
@@adriangaspar8209 I just brought a CA810 and there was an FM audio frequency when I connected the RCA Tuner to the amp. Just as you mention it, it does not respond to volume and it was so low that when listening to normal music it was not perceived. Currently I do not have the tuner Tuner connected to the CA810 tomorrow I will test to see if it continues to happen. I recommend that you ask the "Santiago de Leon Audio" channel here on UA-cam, insurance will tell you what to do. Tomorrow I will do the test and if the FM noise continues I will ask Santiago.
Mine has just recently developed distortion on one channel and complete silence on the other. Any idea what may be the problem? Also, as a non tech, is it something I can repair myself? Thanks for your help.
You can't repair without the proper tools but there are things that you can check. It could be in the pots or the switches, turn on your amp and run music though some speakers or better headphones, work (back and forth, on and off) each pot and switch to see if you hear the sound coming back, if so clean appropriate pot, with faderlube, or switch, clean with deoxit protect with sheild. Same setup but take off case, find the relay (the input selector rod is pointing at it) and tap it with something that isn't electrically conductive (like a wood stick), if the sound comes back when you tap it then you need to replace the relay (not that easy as you need solder skills). There's more you can do, like figure out if the problem comes from the amp section or the preamp section (using the preout/main in terminals on the back, go to audiokarma and there's probably posts on how to do this). More complicated, since it's old, 45 years, it's some transistors although this usually affects one channel (each channel is independent) or the whole amp (power supply issues).
Although this might be many things, it could be a result of a failed transistor in the final amplifier stage, or a leaky and shorted capacitor in the same vicinity. If you wish to restore your amp, these items are routinely replaced anyway by a qualified technician. If you did open it up and get lucky (maybe you visually spot the bad cap, and successfully solder a replacement in its place), it would be akin to retreading just one tire on an old car with four old tires. Soon, the next-weakest part will likely fail, and then the next. And if it's not worth repairing, and you really like the amp, why not try to find a used working model, or a similar one with more features, and then use the amp you have for spare parts. - j q t -
Brilliant video that covers just about everything... Tony did you use white Led's or blue? I couldn't tell if they were lighting up the meters or not under the bright lights later on in the video.. Anyway great job and keep the great videos coming.
Hi Tony. I’ve been watching all your videos with great interest. Do you think there is any benefit in leaving audio equipment left switched on permanently in terms of extending the life, for example will the capacitors eventually degrade anyway or wear out quicker if left on 24/7 vs thermal expansion etc? Thanks, Andrew UK.
Good question! A lot of the medical equipment I service at work is left on 24/7 for many years. Although the capacitors would stay "formed", the added heat from being on all the time will cause the caps to dry out and eventually fail, often sooner than equipment that is turned on and off. As for audio amps & gear, the warmer the amp is, the faster it will degrade the caps. My guess is that the caps would last the longest when the equipment is used normally. Each time you turn on and use the amp, it will help the caps stay properly formed. By turning it off when not in use, you will prevent the caps from being exposed to unnecessary heat. All of this applies mainly to electrolytic caps, due to the chemistry used in the electrolyte. There are many different grades of capacitor and the life expectancy & heat tolerance can vary greatly, especially with higher ESR caps. Its important to read the datasheet of a capacitor before choosing it for a specific application. Hope this helps!
go too high in voltage can modify character of amplifier because the higehr voltage the higher ESR (capacitor resistance) The esr is a parameter taken in consideration in manufacture conception
I love the old designs, no nasty black block output modules, like sanken (Sunken lol ). I have an old pioneer SA-706 beast, love the thick aluminium and real moving meters :-).
Is there any particular reason you didn't up the voltage rating a bit when replacing those 100µ/35s, like 50 or 63 V? Those wouldn't look as lost in the old footprint and I'd expect better longevity (bigger = less risk of drying out, lower ESR, higher dissipation handling) with no downsides that I can think of in audio applications. (IMHO electrolytics needing anything close to rated voltage to stay formed can be filed under urban legend. They will still reform = leak current under much lower voltages, albeit more slowly. Given the same chemistry and quality level, I'd always be inclined to go for the thicker dielectric = higher voltage rating, which invariably reduces the risk of the cap going excessively leaky eventually. Besides, caps have shrunk because dielectric layer quality is much better-controlled these days, which also means that a _good_ old cap may actually withstand much higher voltage than what its necessarily conservative rating indicates. Being too skimpy may result in an effective downgrade from stock level, which is not what you want when putting in all the effort for a recap.)
I have the CA-1010 since i bought it new in 1976 and just had some work done by a 40 year experienced tech . The repair expert commented how well these amps are built and how output wattage is very conservative . The comparable replacement model today is $3100 vs the $475 I paid in 1976. When running at low power levels this amp is running pure class A . I love that we still have some master tech's like you to fix our vintage gear. Thanks for doing this art of repair .
Great amp. 3-4 weeks ago I rescued a CA-810 from being scrapped. Yes, some people are insane and I was glad I was there at the right time and rescued it. It works as it should, but I should restore it and also replace the relay which takes a good while to activate. Need to replace the lamps too. Great video! Greetings from sweden.
This is a superb restoration of an excellent integrated amplifier. In addition to failing LEDs and capacitors, cold or weak solder joints on some of the RCA connectors often cause trouble, as people are tending to use these wonderful amplifiers that came in many different models for over fifty years now! The potentiometers on these amp's, as well as the front panel switches, tend to often become very electrically noisy after all those years, and it's crucial if you repair or replace the 'ganged' Volume Pot's that these are precisely matched.
Yamaha amp's are notorious for the way you could set the volume very close to zero, and still get the same signal level and thus sound pressure at both the left and right channels or speakers, something many other amplifiers do very poorly. Noisy pot's are almost always an issue after five decades, whether the amp is used little or lots, and while these can usually be cleaned and made to work again for another year, at some point, the 'snap, crackle, and pop' becomes too annoying, and these must be replaced.
It's important to try to find the matching pot's, especially for the Volume Knob, as these are 'ganged' and this requires a special tolerance value so they will behave similarly. The design of the preamp circuit in all Yamaha Natural Sound amplifiers is very precise, and so these amp's usually come with shunts for the unused (usually Phono 2) jacks. If you pick up a used amp, these shunts will probably be missing, and a simple 25-cent part can help keep the amplifier running quietly. There is also a Ground Wire Jack for the turntable, and yet some models might run quieter WITHOUT using this ground connection!
As many people are adding turntables and enjoying vinyl, learning about stylus designs, direct-drive vs. belt drive noises, and RIAA Equalization Curves, and yes, even grounding circuit noises all need to be examined. And let's not get started on disc washers and special, 'designer' cables!
Anyway, the reason I am posting is with regards to the Yamaha Loudness Function Control: Your demo of the Loudness Control was sufficient and adequate to illustrate how it works, but it would be good to also show the way Yamaha actually intended this to be used: First, with the volume low, you turn the Loudness Knob (the smaller of the two knobs) to FLAT (all the way up), and now you turn up and set the main Volume Knob to approximately the highest volume level that you intend to use, which may be at level 2 or 3 out of 10 for background music, or 5 or 6 out of 10 for moderate listening in a group of three or four friends, or up to 7 or 8 out of 10 for a party! (That's the beauty of these very low Total Harmonic Distortion amplifiers, is that you can actually use 75% to 80% of the range of the volume setting, and with such good design and a high damping ratio, the amplifier will rarely begin clipping, even into a 4-ohm load. Try that on most other amp's; they will often clip terribly once the volume gets beyond about 6 or 7 out of 10 (I'm try to resist saying, "This goes to Eleven!")
Set most integrated amp's volume knobs beyond about 60% of the way toward maximum, and it will begin distorting and clipping like mad! Anyway, now that you have your preferred maximum volume set for the current listening session, then set the bass and treble to their preferred settings, which should be as close to zero as the room acoustics allow (the tone defeat settings remove the equalization knobs from the circuit entirely, in order to further reduce distortion and possible noise).
Okay, now you are ready to use the Yamaha Loudness function as intended: just crank the Loudness Knob back down to whatever level you prefer, and the lower you turn the Loudness Knob, the more bass and treble boost gets added, essentially to compensate for the way our human ears tend to "roll off" both low and high frequencies as the sound pressure level gets reduced. It really helps to understand the way the designers intended this to be used if, as you alluded to, you show the curves of both the low and high frequency 'boost' that gets added gradually with this Loudness Knob as you LOWER or turn down the Loudness Knob (and not the Volume Knob).
Therefore, in summary: you set the peak or maximum desired volume for your current listening session with the Volume Knob, then adjust the equalization (bass and treble) if needed (or use DEFEAT for FLAT response), and from then on, use ONLY the Loudness Knob (the smaller knob) to adjust your volume! In this manner, unlike most amplifiers in which Loudness Compensation is a SWITCH of "All or Nothing," the Variable Yamaha Loudness Knob provides a continuous and "smooth" boost of both low and high frequencies as you reduce the volume via the Loudness Knob! Anyway, that is the way the designers intended their system to be used. - j q t -
Thank you for this video. I've been using a Yamaha CA-710 since about 1977 - 78. Never felt the need to change it. 40 years service and only been to the shop once and still looks brand new! Even the light globes are originals. As soon as COVID is over it will be going in for it's 20 year service and re-cap. Might even spring for a shielded AC cable for it.
I can't tell my resistor from my rectifier, but this guy is easy to listen to, and it's a great pleasure to watch someone do something well.
Absolutely beautiful amplifier. Wish the new stuff had some style like these older amps. Great video
I had Same issue. Turn balance to right or left and no sound. Stuck in mono mode. I Did this repair and it now works in stereo mode. Saved me $$$.
I've been working on electronics for decades but I always gain something from watching your videos. Some versions of that old glue can become conductive when they get old. As you can imagine, that can cause all kinds of problems. I had to spend a lot of time scraping off old glue on a piece of gear I was repairing because it was shorting out parts of the circuit and causing parts to fail.
Also, I use aquarium grade silicone glue because it does not have any corrosive chemicals that might harm fish.
Keep up the good work!
The silicone Tony uses is what I used for aquarium repairs !
Very detailed and systematic narration, I am very thankful as a beginner.
Very nice amp and great job .. love the thorough explanations of the situation and cures. YOU are one of the very best here.!
Paul and Tony's Stereo closed their doors for retirement at the end of June! Thanks for your videos.
I worked for a Yamaha Service Center in the 70's and 80's. The NEC transistors are not original even if they appear to be. Yamaha always used Toshiba transistors for the outputs. Also, they would never use different types in different channels. Thought I would clear up that thought.
I've always called them Yamahey.. because of their (imo) lacking quality in both sound and buildquality - never liked them.
Thanks . Really good video. In 3 days going to pick up this amp (350 km in one way). As the owner sad, he has it for 40+ years, never had any problem. Nobody Touched it inside - what I like. I'm an industrial electrician for more then 25 years, and in this aria, my last project for fun was sansui au 7900, the owner was happy. Hope this video will be very helpful to restore a new toy. Right now I have KEF 104/2 and Tannoy srm 12x with only one amp - Marantz PM 8005. Hope this amp will work well with one of those speakers. (They are realy different :)
I've had a ca 800 since the late 80's. It runs well but due to it's age it'll head into the shop for some work in order for it to keep working for a long time. Thanks for the videos!
Fabulous amp! And it has a Class A/AB toggle -- Class A is special!
Yes, the Yamaha CA-800 has the coveted Class A circuit, with a front panel switch that can dim the lights if you're hooked up to a cheap extension cord with the Christmas Tree lights! Class A is the amplifier equivalent of setting your car's idle speed to be 7500 rpm! Greta Thunberg would probably scream, _"How Dare You?!"_ and _"Blah! - Blah! - Blah!"_ . . . but calm down, child, it's a few hundred watts! I had the Yamaha CA-400, with its truly useful Microphone Mixing, so back in the 70s and 80s, I could record stereo sound and mix spoken dialog (such as when my infant son was learning to read) and make numerous other recordings with stereo music background, and it really makes quite a difference! - j q t -
I had the ca1010 with matching tuner. These are great amps. Old yamaha natural sound was good stuff.
Those THD #'s are what one can generally expect from that era Yamaha! They were always my favorite equipment! We wouldn't even consider dropping down to Pioneer! The meters were a nice bright even pale creamy white color...no blue whatsoever? And yes, we purchased these new in the mid-late 70's. We chose our equipment by reading the specs! THD & IMD also the frequency response as well as the S/N ratios. If the numbers weren't there, I didn't even want to hear it ! The only problems I can remember were replacing the wheat lamps every now and then, but well worth it for the performance...
I acquired my very own smaller sister amp the Yamaha CA-510 amp brand new on my 15th birthday back in the fall of 1978. I also remember seeing and experiencing the more powerful CA-810 next to my soon to be purchased 510 in the sound room at the local stereo/record store A&B Sound in Victoria Canada a once iconic Canadian music store chain. I loved that amp, when it was in its prime in the late 70's to early 90's. Sadly the old CA-510 finally died in smelly, smoky fashion in the early 2000's. I would love the get the new Yamaha retro CA-inspired A-S1200.
I've got one of these, been packed away in storage since downsizing. I really miss it along my Tannoy Ardens. It's a beautiful amp highly recommended.
Hey Randy Alexander@ I also have a Yamaha 810 Natural Sound amp and I still use it, and it still sounds great. 👍
Thanks for the video I just stumbled onto your channel. I've been using a CA-800 in my system pretty consistently for about 30 years. It's a little smaller than the CA-810 and doesn't have meters but it can run in class A.
I've got two Yamaha M60 amplifiers (both are in protect mode) in great condition. If you'd be interested in repairing one for me, I'd be happy to give you the other. I've also got two Advent 350 integrated amp / tuners.
I really enjoy and appreciate your videos. Thank you for taking the time to share your knowledge with us. 👍🙂
Hi, did you ever get them fixed please?
Great job Tony I restored one of these couple a weeks ago I really like the CA810.I actually got the DC offset lower by closely matching the differential pair for each channel got it down to around 9mv or so. But heck 20mv is no problem really enjoy your videos.
I owned one and loved it -especially the slight green glow to meters. Beautiful sound and looks !
Nice one Tony, good timing as I am about to put a CA2000 on the bench for restoration!! I'll make sure I check those sockets just in case!! Looking forward to the next one.
Any special technique needed when pulling the output transistors out of their TO-3 sockets? Just remove two screws and pull out? Inverse for re-installation?
hi from Turkiye, it is very nice of you to share knowledge of the parts.. Thank you..
Thanks!
Thank You!!
Very handy, I have a CA-610 that could use a little love. Time to have a look.
I have owned a CA 600 since new in 1976. The loudness control is used very differently than you were using it. It is designed to make up for the perceived change in the sound as the volume is reduced. How you use it is to set loudness to FLAT then adjust the amp to as loud as you would ever want to listen. You then make any adjustments to the tone if you want to and from then on, you use the LOUDNESS knob to reduce the LOUDNESS you are listening to, you do not adjust the volume knob agan for normal listening. The LOUDNESS knob then is used the way you would normally use the VOLUME knob.
That's not how we used it. We pretty much always set the tone controls to flat. The only time we used the loudness switch was at lower volume levels. We only used the volume knob. I never heard, nor saw anyone else using the loudness switch like you mentioned?
I noticed the Pioneer KP-500 car stereo. The best I ever heard.
I noticed that car stereo too, my best friend had one of those as well I had a flash back as soon as I saw it.
Great to watch. Have purchased a Pioneer VSX838 bout 6 years ago. It lasted just under 2 years. My old Pioneer SX300 1973 is still going apart from the festoon and stereo lamps. Looking like the best and most reliable are the old'ns. Pioneer SX1050 would be nice, they are about.
I had to change out the pre-main jumper RCA's on my amp due to one being intermittent. I put the heat shrink on the replacement RCA jack before installing it. Thanks for the tip and it might save some frustration in the future. I am using jumper wires with actual RCA plugs, not the solid, bent rod type, though.
Yamaha make fantastic well built pieces of kit, superbly well designed and put together an engineers dream to service and repair, i have owned a number of yamaha items and i have to say i am a massive fan of their gear, i have to say on a personal note i think their gear is very good value for money great specs and performance
I have CR 800 bought new when i was 16. Still sounds good but should i go into it?
nope, still sounds good. wait until/if something breaks and then have it completely restored.
I just bought a ca-610 off ebay, I wanted an 810 but they are tough to find. Hopefully the 610 will be powerful enough.
Update, received it today and all I can say is wow, the photos do not do it justice.
I have a CA-810. Today I found my left VU meter needle stays at the max to the furthest right when power is on. I had tried to turn on/off, and unplugged the machine but no use. Sound come out from both left and right without problem. So, is the meter “dead”? Anything I can to to restore it? Many thanks to any advice.
A trick for the LED lighting. Use fine (+1000) sandpaper on the outer surface of the LED. This diffuses the LED to a bulb like glow, which is a very even one.
Very informative, and interesting..just found your channel and after watching this I'm subscribed. Thanks for such great content, from UK 🇬🇧
Very nice! Whats your opinion on replacing filter caps? Historically, I always replace but trying to find anything in the 12000uf to 18000uf 40mm casing is about impossible. Digi, Mouser, all 0 stock. I'm to the point of salvaging early 2000's amps for filter caps.
I recently fully re-capped a CA-810 with Audio grade Nichicon caps including filter caps as well, but I still can hear light Humming when idle, it's not increasing even with full volume at idle, stays in same level. also it goes away when de-coupled pre-amp and power amp. mid point show 1.3mv and idle current is healthy as 20mv. looking for a help.
The sub board with the switch is often damaged. Based on its location. Inspect the traces and joints. Some bypass the board entirely. Jumper wire it and see if it goes away as a test.
I have the same problem with a HK 680. I replaced the large capacitors but it just sounds better LOL, the humming doesn't stop. Initially I thought that the humming derives from the transformer but they are only the fins of dissipator on which the final transistors that vibrates. The bias currents in mine are perfectly set at +-21v, I noticed that decreasing the bias value also decreases the vibration. It could be the pre-stage transistors that should be changed (all of them). In the end I think it's just the flaps that are too large and poorly designed.
@@Poppinwheeeeellllllieeeeez Thank you
What filter caps did you use ?
Nice video & excellent explanation coupled with deep knowledge of electronics. Cheers.
Just proved my SU-V3 still works with the help of this video! First amp my dad bought me as a kid. So glad to know it still works!
Need to clean it up properly though - I still have to wiggle the input selector to get both channels to work.. But not sure on the best method / what to use.. Any advice?
Hello sir, i understand it’s been 5years ago. Could you tell me ….i have 2 resistors on my PCB board for the lights. Did you replaced two of them or just one for 8.2k..? To install led bulbs. Thank you!
old amps just have that sound quality that is unmatched today.
This is so cool I have one of these i got at an estate sale and we ran it a bit but a cap went out or something so its been sitting. Hopefully i can check this out and get it running!
Holy shit... My room-mate/best friend had that exact amp ! That was ~1982. We had some stage type Cerwin Vegas, a wood/glass Oracle turntable and I think it was a Teac dual cassette deck. Picture a lot of "brand new" Van Halen, ZZ Top and such. With a good dose of Pink Floyd, Zepplin, Stones... good days. :)
Great video as always. I was wondering what brand the cleaning pen was.
Nice work, great video. I have a Yamaha A-700 that I would like re-capped and serviced like this one.
How much does typically one of this repair/restorations on vintage gear costs?
I charge $80-100 full recap
nigel mahabir Hi Nigel, I have CA-1000 model. It works perfectly, but I would like to restore it to even more perfection, which for this price is very execrable. Where are you located? I’m from Toronto, Canada. Please return to me. Thanks.
thanks for posting! .. Yamaha's don't get seen much .. my experience has been they have high negative feedback, leaving them cold and sterile ..they also seem to be lacking in Bass
How much did you charge for this restoration and what is your turn around time if I send you the exact same amp. If I had to guess off watching your video my speaker channels are bad. Great video I have none of your equipment or any skill set in this area of electronics. I've already been ripped off for $180 from a local shop that did nothing other then turn it on and gave it back. Also, brand name and dealers that sell that cleaning pen you used. Thanks
Thanks so much Tony for your teachings this art of radio & music making machines of the good old days, I have a Aragon 4004 mk2 amp that pops & hums I bought new maybe 20 yrs ago & can't seem to find anyone I trust to work on my baby I live in LA aria do you know a good repair technician in L.A . Or close to me in California were I can get this jewel fixed thanks so much Tom...Joe Logston
would anyone know the Theory of operation for the Safety relay in these amplifiers?
Great stuff! Would love to see a onkyo unit, like m5060r or p3080 maybe.
If the signal transistor leads are tarnished it can migrate into the body of the transistor, cause noise, low gain, leakage etc. 40 year repair tech. Examples 2SD458, 2SC1345.
Not 2sd458 but 2sc458 are the transisors you are referring to.
Tony, why did you change out the output transistors? Did I miss something as to why?
I have one of these amps. Do you still do restorations and what might the cost be?
Well done you one of the best fully explanation.
If the main filter caps ck’ed good and you didn’t replace them, did you check any of the other caps you replaced to see if they ck’ed good? Or was it just easier to replace the small caps then try and source and replace the big ones?
Watching this on a new SONY 49 inch screen makes my day. Today we got 36°C (97° F) a new all time record for my country.
1959Berre , what the hell does your comments have to do with the video ??
NOTHING troller man
Hi! Thanks for posting this. I have the CA-2000 that looks very much like this. The power switch/knob got bent and half broken during shipping to me. I need to take the face plate off to get to the switch/knob to fix it but am not sure how. To get all the obstructive knobs off the face plate, do I just need to pull them off the shafts? I've tried but they're really tight so I'm afraid that I might break something if I pull too hard. Do I also just need to pull the balance ring out and it will come off the shaft? Please help and show me how! Thanks!
I've found that on some audio equipment the knobs will sometimes have "set screws". They're usually a micro flat head or phillips screwdriver or possibly an Allen wrench. Hope this helps 🙏 👍🙂
could you have push that metal part that was shorting out ...back into the jack, like with a screwdriver?
With fan cooling base I used to drive 2x 200 watt theatre bins for the town discos and parties ('76) Later used last summer driving outdoor sound for village event- such good amplifiers...
Plastic has a softener in it. We used to make it at Monsanto's in the seventies. It is not oil. The name was S160.
I have a Technics SA-410 that comes on and clicks but no sound. Where can I send it for repair? It made a pop when it quit working. So I know it fried something.
But when you were talking about the filter caps it is better to have two bridge rectifiers filtered in between each other with a small capacitor before the filter caps this is better than replacing the original capacitors for bigger ones. Do you ever do this as an upgrade and maybe using 4 to split the channels.
That relay are the contacts silver you won't silver contacts. Why did you swap out the power transistors what benefit are these new ones you put in?
John sweda It was probably just so both channels were matched.
Great video Tony...as always!
I have same amp. Original owner. All 4 original transistors are Toshiba.
Hi what is that player on top you have thanks.
Breeze Audio DV20A (:
Thank for that why the sad face:(
That must have been a typo. :)
Have a great day. :)
I just bought one any thoughts on sound? My sub is powered and has rca can I connect to preouts?
No you can't, you want to run your l&r speaker wires to the back of the sub into the speaker inputs then run wires to you speakers.
Those output transistors are matched pairs right? Just two sets of matched pairs. Just curious.
Output transistors don’t really need to be matched. As long as the betas are at least 60, it’s fine. Beta droop at high current is a bigger issue. The bias circuit sets the idle current. 20mV across 0.47 ohm is a 42mA. About what I’d expect.
And if there’s an adjustment on the input stage, you’ll be able to zero the output. Input transistors ought to be matched.
The NEC outputs are not original - probably been in there a long time though.
dear if you comper sound quality which is best for you yamaha or marantz ?
I had a CA 410 also a CA610 and yes they r under rated I miss them and always wanted the CA 810
enjoyed the vid, i am old school so i like old stuff too. would you be interested in restoring an old nakamichi 550 cassette deck? i've had it a long time and would like to get it back in shape. it's in pretty good condition, should just need cleaning and calibration. it's a great old deck, but like me, it's getting along in years and needs a checkup.
One thing I don't understand. Given the wide bandwidth, and the fact you can compose square waves from a bunch of sine waves, I am suprised the square waves are not a bit better. I know there's a limit to slew rate and such. I play some synths, and square waves generally sound good in spite of the fact the waves are not perfect, so maybe it doesn't matter that much.
Thanks for the comment! There's always a trade-off when designing these circuits. Negative feedback will affect the slew rate of an amp, even if you use transistors with high transition frequency and careful circuit design. There's always been debate over feedback vs low/no feedback. There are pros and cons to both. At the end of the day, what really matters is how the amplifier sounds to you and how it works with your speakers, not how it looks on a piece of test equipment. I really like the sound of these Yamaha amps, but I also like the sound of the Sansui AU-X1 that has very little feedback in the design. They both sound very different when connected to the same speakers and it comes down to personal preference. Hope that helps. Cheers!
Without the filter capacitors the ripple would be in the range of +/- 57.1% around the average dc output of the rectifier.
Just curious, how come you never say the word 'be', as in "needs to be cleaned" or "needs to be replaced"?
I Jus gues I ain't no how ta talk.
xraytonyb doesn't really matter, I still enjoy the videos. It's just something I noticed in every video and had to ask. Haha Keep up the good work.
;)
mikedrz , lol, BE PHOBIC
Regional dialect.
love your style... is there any one good in east Sussex ...UK.
Thanks for your great videos, a big fan of your channel. I have the same amplifier and want to line the phono switch up with the markings. Could you please tell me what type of locking screw tool and size to use please.
We use metric so I'm not sure if I can use. Appreciate any advice on removal and anything else I may need to be made aware of, thankyou.
2MM Allen, just checked the CA-810 I have on the bench.
@@milo963 thankyou
Gigantic transformers , until Bob Carver.
Too bad your source was an Mp3! :( How do you like the Breeze audio DAC though?
Hi i have the same amp and was woundering if you can restore another one for me i miss it Yamaha CA810 thanks
Interesting video as always. BTW, why do you use the PC scope in preference to the Tek? Bigger display?
I just use it for the large display. It works fine when looking at audio signals and shows up well on videos.
What scope program are you running on your computer? By the way, your videos are excellent!
Just bought one on ebay. Mostly because of this, and all the rest of xraytonyb's video.
Hello, nice video, thanks! I recently bought this machine type and I use it for listening to analog sound from vinyl and also CDs. Connected to a pair of floorstands, the sound is brilliant! Machine runs fine, yet there is a small inconvenient: I hear radio interferences in both speakers, the sound is almost imperceptible but mostly at late hours when the room is very silent it gets annoying. Radio sound is equal in level on both channels and it is not influenced by the master volume level. It stops only when no RCA sources are connected to the back inputs (any input!). I have to say that I use very good interconnect shielded cables, that I just bought in order to clear this lead, so I presume that the issue comes from somewhere in the machine. Does this ring any bell? I would like to get it sorted out. Thank you! (I am mechanical engineer, I do not performs electronics repairs myself, but I have quite enough understanding of how things works, I am an old enthusiast of audio systems for home music listening).
Pudiste resolver el problema?
@@JG_Rocca no
@@adriangaspar8209 I just brought a CA810 and there was an FM audio frequency when I connected the RCA Tuner to the amp. Just as you mention it, it does not respond to volume and it was so low that when listening to normal music it was not perceived. Currently I do not have the tuner Tuner connected to the CA810 tomorrow I will test to see if it continues to happen. I recommend that you ask the "Santiago de Leon Audio" channel here on UA-cam, insurance will tell you what to do. Tomorrow I will do the test and if the FM noise continues I will ask Santiago.
@@JG_Rocca So, how is it? Did you found the radio source?
@@adriangaspar8209 this time I plugged in the tuner and all went well. ask to the channel "santiago de leon audio" is the man.
The Preamp is a Class A not sure about the output stages.
Mine has just recently developed distortion on one channel and complete silence on the other.
Any idea what may be the problem?
Also, as a non tech, is it something I can repair myself?
Thanks for your help.
You can't repair without the proper tools but there are things that you can check. It could be in the pots or the switches, turn on your amp and run music though some speakers or better headphones, work (back and forth, on and off) each pot and switch to see if you hear the sound coming back, if so clean appropriate pot, with faderlube, or switch, clean with deoxit protect with sheild. Same setup but take off case, find the relay (the input selector rod is pointing at it) and tap it with something that isn't electrically conductive (like a wood stick), if the sound comes back when you tap it then you need to replace the relay (not that easy as you need solder skills). There's more you can do, like figure out if the problem comes from the amp section or the preamp section (using the preout/main in terminals on the back, go to audiokarma and there's probably posts on how to do this). More complicated, since it's old, 45 years, it's some transistors although this usually affects one channel (each channel is independent) or the whole amp (power supply issues).
@@fernarias thank you. I'll give it a shot.
Although this might be many things, it could be a result of a failed transistor in the final amplifier stage, or a leaky and shorted capacitor in the same vicinity. If you wish to restore your amp, these items are routinely replaced anyway by a qualified technician. If you did open it up and get lucky (maybe you visually spot the bad cap, and successfully solder a replacement in its place), it would be akin to retreading just one tire on an old car with four old tires. Soon, the next-weakest part will likely fail, and then the next. And if it's not worth repairing, and you really like the amp, why not try to find a used working model, or a similar one with more features, and then use the amp you have for spare parts. - j q t -
She's in the repair shop as we speak.
@@thesighcompany How did you go about finding a competent repair shop?
What state do you live in?
Brilliant video that covers just about everything... Tony did you use white Led's or blue?
I couldn't tell if they were lighting up the meters or not under the bright lights later on in the video..
Anyway great job and keep the great videos coming.
I used soft white LED's. When they mix with the blue lens, it gives off a greenish light. I used 3mm LED's so that they don't give off too much light.
The antimold additive in GE Silicone II may be corrosive over time.
I love yamaha amplifier
Ahhhhhhhh Yamaha lover.
I HAVE A CA1010 YAMAHA THAT IAM HAVEING A HARD TIME FINDING SOMEONE TO RESTORE , I BOUGHT IT IN 1982. HELP!!
Hi Tony. I’ve been watching all your videos with great interest. Do you think there is any benefit in leaving audio equipment left switched on permanently in terms of extending the life, for example will the capacitors eventually degrade anyway or wear out quicker if left on 24/7 vs thermal expansion etc?
Thanks, Andrew UK.
Good question! A lot of the medical equipment I service at work is left on 24/7 for many years. Although the capacitors would stay "formed", the added heat from being on all the time will cause the caps to dry out and eventually fail, often sooner than equipment that is turned on and off. As for audio amps & gear, the warmer the amp is, the faster it will degrade the caps. My guess is that the caps would last the longest when the equipment is used normally. Each time you turn on and use the amp, it will help the caps stay properly formed. By turning it off when not in use, you will prevent the caps from being exposed to unnecessary heat. All of this applies mainly to electrolytic caps, due to the chemistry used in the electrolyte. There are many different grades of capacitor and the life expectancy & heat tolerance can vary greatly, especially with higher ESR caps. Its important to read the datasheet of a capacitor before choosing it for a specific application. Hope this helps!
Thank you for your superb reply! Kind Regards, Andrew.
I have a Yamaha ca-410 II. it crackles.
go too high in voltage can modify character of amplifier because the higehr voltage the higher ESR (capacitor resistance) The esr is a parameter taken in consideration in manufacture conception
I love the old designs, no nasty black block output modules, like sanken (Sunken lol ).
I have an old pioneer SA-706 beast, love the thick aluminium and real moving meters :-).
Is there any particular reason you didn't up the voltage rating a bit when replacing those 100µ/35s, like 50 or 63 V? Those wouldn't look as lost in the old footprint and I'd expect better longevity (bigger = less risk of drying out, lower ESR, higher dissipation handling) with no downsides that I can think of in audio applications.
(IMHO electrolytics needing anything close to rated voltage to stay formed can be filed under urban legend. They will still reform = leak current under much lower voltages, albeit more slowly. Given the same chemistry and quality level, I'd always be inclined to go for the thicker dielectric = higher voltage rating, which invariably reduces the risk of the cap going excessively leaky eventually. Besides, caps have shrunk because dielectric layer quality is much better-controlled these days, which also means that a _good_ old cap may actually withstand much higher voltage than what its necessarily conservative rating indicates. Being too skimpy may result in an effective downgrade from stock level, which is not what you want when putting in all the effort for a recap.)
ooh! I've got one of these waiting for attention!