Does anyone else find Clive's videos relaxing? I like to chill with a drink and watch his long videos even though I know nothing about electronics. I love his sense of humor and the weird things he shows off though.
Yep, I'm teaching myself electronics and originally started watching Clive's videos to learn stuff. Now I re-watch his videos to chill out. They are better than a lot of the repeats we get on UK TV.
I wrote this before - I find Clive's wit and mellow Scottish accent very soothing. I use it as an antidote for Dave (from EEVblog), who has an aggressive Australian accent and an annoying manner of speech :) For me the prescribed dosage is 3 Clives per one Dave :-D
Hi Clive! I'm really interested in lighting stuff, and I'm sure others would really love it too if you did more lighting equipment breakdowns like this.
Those 2 rectifiers will separate the ground loop provided that the voltage differential is less than the input voltage. So, it doesn't make it safe against an exploded transformer, but it will (almost) decouple the 50Hz hum.
"That's tacky" - Unintentional pun of the year award goes to Clive... :P I still find DMX to be a mysterious thing, volunteering at an amdram small theatre & working the lights it was all old transformers, rubber cabling, & a mostly analogue desk (did have basic electronic functions like an auto-fade so you could drop the lights quickly on the board, but they'd fade out slowly, that was about it!), then they changed to DMX to upgrade it all, new programmable desk (so program in the scenes lighting & press a button during the performance to change scene, no fun!), LED & halogen lighting, new cabling that I wasn't to touch, it lost its appeal to me, I liked the old equipment, playing sparky cable roulette there was fun when moving lights about (fully against all H&S regs I'm sure) to set them up for productions, but oh well, sad thing is the old lights they had there are worth a fortune now cos of people living in studio apartments who buy retro theatrical lighting for that vintage look...
"...when something goes wrong with DMX it's like 'Disco central.'" I mean, the Reggae thing worked for Snoop Lion -- can you blame DMX for trying to bring disco back?
Just wanted to say thanks for making some of your PCB's available online, got the snowdrops and LED flower PCB's in the mail today, time to track down a suitable power supply and make things!
Surprisingly well made circuit board and it wouldn't be much of a problem to just desolder the bridge rectifiers and feed the two circuits with different power supplies to complete the isolation.
not many Mux and Demux videos around. Applied for a network engineer job a while ago and looked into it all. Interesting stuff. Missile guidance systems and Seeker heads are very interesting too.
well this video, and the mention of getting a quality power supply probably answers the question as to why my Thomann and Strand branded DMX buffers/isolators have 240volt inlets, with the PSU inside, thus preventing it being powered by a bad external PSU.
Mr. Clive. You need to get yourself a Post Office box, a 'mail bag' upload schedule. I got, literally, a metric tw*t load of electronic doodads you'd just go nuts for. Disassemble to your heart's content.
If it's got AC going in, and 2 separate rectifiers my guess is that that at some point in the past there was meant to be an isolation transformer in there.
Curious unit. First clue it's not exactly high-end is that it's doing DMX over 3pin XLR connectors, not the usual 5pin. As to the power isolation; it might be quite easy to fix that by the addition of any of those 5V DC isolator modules made by Murata et.al. You could easily fit one of those inside the case and feed its (isolated) 5V output to the DMX input side. Whenever I do DMX that's usually the power isolation I go for.
The Problem is that all the 8-output DMX connecters are Junk the 3-pins sockets are not soldered to the back of the connector Luckily for me I found one in the DMX cable connector & I found that the Dmx Sockets are two pieces & they have a Sleeve (Socket) inside the connecter & they are just a VERY loose press fit to the back of the connector & Most Pins, Sockets are one solid piece & this is a very strange design & Wow! this being a Very Loose connector could cause all kinds of problems I even cut the connecter apart to verified it! so I replaced all 8 of the output connector & it works Great now
I Bought a bunch from E-bay "3-Pin XLR Jack Panel Mount Connector" it better to pick out the ones that are the same Diameter of the DMX unit holes the last ones I bought were to big so I had to drill out the hole
Well, it doesn't look like it would play well with RDM. But I suppose Christmas tree lights and LEDs for use in architectural lighting probably have never heard of RDM. So as a simple buffer in a small setup it will probably work fine. It's likely this was intended for luminaries that are running on 2-prong isolated wall warts, so it may be that the only real system ground will be at the controller, if that. Since this thing would probably be at the controller too (so you can do a star network) it may never see a ground differential between any of the outputs.
If that board was glued in, methylated spirits (denatured alcohol) works really well for removing hot glue. No idea how it works, but just by putting a little on so it gets drawn in and under the blop of glue and it comes right off after about 30 seconds.
The proper way to isolate the power supplies would be transformer coupled DC-DC converters e.g. a TRACO unit or one made from discrete parts. But that would likely push the price up. I may be able to send you the PCB from an industrial fully isolated RS485 converter (KD485) but it may have to be a faulty unit, I usually repair them but it's not always worth it.
I'm a musician among other things. I've had several DMX buffers which gave me nothing but headaches. Now I know why... That said I've recently gone to a wireless system. I don't know how my system would fare in a large installation because I don't know the actual range of my transceivers. I use a Chauvet WDMX wireless transmitter. and the corresponding Chauvet D-FI Hub wireless DMX light transceiver to control the lights directly. Now the manufacturer says that the transmitter has a range of around 500 feet. I've never tested them at that range as I don't usually position them anywhere off stage. I'd be curious about your thoughts as they are rather expensive being approximately $430 for the transmitter and around $100 for the receivers.
Rapid Electronics and RS Components are trade only and are not available to the General Public. In Ireland we had Peat's of Parnell Street for components and hifi. They have closed their store in Parnell Street and now THEY are trade only.
I'm surprised you didn't comment on the fact they used 3-pin XLRs instead of the more common 5-pin. (I know, there's a fair amount of lights these days that come with 3-pin connectors, but they're not all wired the same. Much safer IMO to use 5-pin everywhere and use an adapter that comes with each instrument to go down to the right pinout for that instrument.)
The point of three pin is that it's cheaper and the cables are cheaper, so it seems unlikely that the majority of the fixtures that use it would come with an adapter to five pin. I mean, a given shop could do that as a matter of course (but it's easier just to replace the XLR outs), but I don't think it's normal.
+Jasper Janssen Cables are not actually cheaper. Sometimes people cheat and use microphone cables for DMX, but because they're not twisted correctly, they cause similar hard-to-diagnose issues with flickering/disco-style effects due to interference. Using 5-pin cables is a great way to help ensure you're actually using a DMX cable.
Quentin Smith like I said, three pin XLR cables are cheaper, because you can easily use crappy mic cables instead of proper 120 ohm shielded twisted pair. Plus proper Dmx cables actually connect both pairs even though only one is used, which means you need twice as many center conductors. Plus the plugs and sockets actually are significantly cheaper on three pin than on five, because they're used on audio runs in great volume.
They work a lot better after I fixed them all by replacing all the 8 DMX output connecters w New ones it was a Lot of work but worth it & still a good Deal,,,(I use a Bunch of Them which makes setup for live shows quicker & less cable runs and in Parallel)
Would love to see a large rig on a dodgy signal. My rig only has 13 effects on a DMX network and I can confirm that berserk is no exaggeration with only that many.
There is so much space in the case, you could easily mount a secound power input, break the traces of one of the supplies on the board and solder a pair of wires to the second input.
So, solder in another power input directly to one of the bridge rectifiers and you're golden? Seems like a really good alternative for temporary installations.
Most serious light/sound/stage companies usually buy proper DMX splitters from Martin, etc. You usually don't want to gamble on neither the power supply or the actual DMX splitter itself :P
Although this should work, the proper DMX standard calls for a 5-pin connector. The reason things like this get around this fact is that 2 pins are for future use and not currently used.
Hm, perhaps they got a young graduate (or whatever they have in China) to design it, and he did it by the book, or by the data sheet. Where the data sheet showed 2 power inputs, he just commoned them, and was pleased to see it worked. If you needed isolation it'd just be a matter of desoldering one of the rectifiers right? Ideally the one feeding the input circuitry. Then as a bonus you could wire in a lower-voltage DC supply so the 78L05 wouldn't be working so hard. I'm surprised at how nice it is, I was half suspecting a load of resistors and nowt else, maybe a couple of transistors or an opamp or something to drive the outputs all paralleled together. This is pretty much textbook, literally I think.
Based on your description should I treat this product more like a hub/splitter? Meaning, a convenient way to install cable by home-running vs daisy chain. Lastly, should each of the 8 outputs be terminated with a resistor at end of line?
Hi Clive, I hope you don't mind the slightly off-topic question, but you seem like the best person to ask. I'm planning on installing some home automation gear to control my upstairs lights. I want to use dmx dimmer packs, the type with cable terminations, opposed to lamp sockets. Each channel will control a room's lighting. I want to power each pack from the radial circuit for the upstairs lighting (as this will no longer be used, as the packs will distribute power). Do you reckon I'd need another DB secondary to my main consumer unit, with an RCD for each dimmer pack? Thanks :)
You could power a multi-way dimmer rack from a single original lighting circuit breaker. I tend to recommend traditional wiring if possible as specialist wiring can make life difficult in the future for "ordinary" people when the control system fails.
Full isolation is just an illusion. All DMX equipments have a ground connection that ties one to another indipendently by the dmx cable. The point is that dmx cable is balanced and the opto isolator led sees the voltage difference between dmx pin 2 and 3 with absolutely no reference to ground or earth. It's like pseudo-balance in audio cables (ex. Shure radio mics do it). Doing so it can cancel common mode interference and ground loop problems.
Noob question: do you have to have some kind of special power supplies if you were to make this fully isolated if you were to disconnect the rectifiers from each other, or would any two supplies with their own transformers, rectifiers and smoothing caps work? i guess capacitive droppers are out of the question as they are actually referenced to the mains they are connected to
if the grounds of the two supplies are not tied together then it should be isolated well enough. given it deals with digital data I would expect to see a capacitor right at the power and ground leads of each chip.
There can be significant ground voltage differences between parts of large arena's particularly if separate substations or generators feed each section. So for proper isolation it would need to be able to deal with tens of volts of ground differential or more.
No. Just providing two separate power supplies at the unit. Most actual isolators have two transformers inside them to provide full mains voltage separation between input and outputs.
Those connectors look like the ones in 3 pin computer fans, which use these colors. I expect that due to economies of scale, that particular color arrangement is the cheapest.
I haven't actually a clue about how the adverts are processed. I choose the pre-roll skippable adverts because it gets them out the way before the video.
Quite an interesting device. So it basically just amplifies and repeats the same signal. I was thinking it would work more like a network switch, where it could be accessed and it would assign subaddresses to things plugged into it. Didn't know DMX was such a simple standard. Also, is DMX one way, or two way? One question @ 4:25. Why would ground be Yellow. Green or Brown would be ground if anything. Black if the power supply is ground referenced. Yellow is almost always +12VDC on logic stuff, some sort of signal wire or in the case of AC, it's hot.
The UK earth/ground wire is a green and yellow striped wire. Plain DMX is a very simple standard, but you also get a modern version called RDM that can communicate both ways and also allow the assigning of addresses to lights remotely.
bigclivedotcom Makes a lot more sense now why that one power supply of mine was colored in what I thought was very nonstandard. Wired hot to ground the first time around and that wasn't very nice when I went to switch it off and unplug it see what was wrong. A bit tingly to say the least. I do think I read up on those colors afterwords but I appear to have forgotten once again. Quite interesting about the different types of DMX, might read up on that a bit. Thanks for the info.
Yes, DMX512 is a simple protocol indeed, which is great since you can use the cheapest microcontrollers to decode it, meaning cheaper stage lightning. It also delivers its data deterministically, i.e. you can be sure that all 512 channels are updated at least 44 times each second (which happens to be just enough for our eyes not to perceive flicker). And should a bit error occur, it will be visible but at least corrected immediately. More modern protocols have much higher throughput, more channels, bidirectionality etc, but lack some of these basic features.
Just a question, are the outputs of those bridge rectifiers commoned in any way or are they both isolated from each other ? If they are isolated the cct may well be pefect without using 2 external supplies.
Ground differences are ALWAYS present. We cannot avoid them. Power cables act as transformers that induce currents to ground prong so you cannot eliminate ground voltages between grounded electric equipments. Eliminate grounds connections means serious electrocution danger. (There is a good text if you like, easy to read "UNDERSTANDING, FINDING, & ELIMINATING GROUND LOOPS IN AUDIO & VIDEO SYSTEMS" written by Bill Whitlock, you can find on Jensen transformers site).-- In this case we try to feed a clean DMX (or audio) signal to the equipments. The opto isolator at the input is a good way to RECEIVE a clean dmx signal using the pseudo balanced (or fully balanced if the dmx controller out is fully balanced) cable. A star connection to different dmx equipment (as is this splitter) always create ground loops because connects together the equipments grounds at the outputs of the splitter via dmx cables. The only way to not connect equipment grounds togheter shoud be an opto isolator at the input of each MAX485 and a separate (not grounded) power supply for each of them. Or one only power supply and a transformer on each output. Obviuosly these are expensive methods. Fortunately DMX is not audio signal and is inherently protected by his "high" voltage (compared to an audio signal) and by balanced cables. -- I use this splitter in a theater to receive the dmx signal after 50 mt of dmx cable and feed 2 different lines of dmx fixtures. It regenerates dmx signal and avoids overload dmx connection splitting it with different buffers on the outputs. For the price is more than i expected.
Not sure why people are really wondering too much about the isolation of power supplies on such a cheap unit not intended for professional use. Strictly speaking it doesn't even conform to the DMX standard as its got 3 pin connectors when the standard specifies 5 pin connectors. $0.02
Bridge rectifier... on DC? I'm not an electrical engineer of any sorts, I don't know much about this stuff... but why do you need a bridge rectifier for DC? Unless it's for making sure the input polarity is correct, like + is + and - is - if you use the wrong power supply?
The bridge rectifiers have some merit since they let the lighting desk and lighting fixture ground voltages diverge by 12 V (when powered on) without creating a ground loop. Replace the buck converter with a flyback or other isolated converter, and you would have a real isolation barrier for almost the same price. Still not very useful though, since you want all 8 outputs to be isolated from each other too.
I find it interesting that it seems to use Cannon Plugs to plug the light control cables in since that's what microphones use. Also, what are those little white three-pin connectors called that plug into the circuit board? I see those all over the place, mainly on the little rechargeable battery packs that those hand-crank emergency radios use.
I've seen some gear using a supplied external PSU with an AC output (higher than 12V) so rectification is needed on the board inside the gear. I can't recall if using a DC PSU will still work the gear properly..... Telephone equipment (UK's BT) often used PSU's outputting AC....
been tearing my har out troubleshooting randm flashing/twitching of lights in a venue. been fine for a while. would come in and it would be fine, then other days it happenns. im not a lighting tech, recently discovered that dmx cabling is different to audio xlrs, so thats 1 issue, then found out that after certain amount of fixtures need a bufffer. we have 16 movers, 14 led pars... i never installed the cabling, did give instructions but it wasnt followed, the pars got installed first and wired up, then movers were added, pretty sure instead of goinng from first closest light and going round, they just wennt from last light.... cabling far too long
Just looking at the DMX buffer before it's opened, I wouldn't even touch it. When running shows, you want as close to 100% reliability as possible and this... Well... It looks like you'd be better ff using a Y-split.
Quick question, are you sure those are bridge rectifiers? Cause it says the input is DC so why would they need a rectifier there? If I had to guess they'd be small dc-dc converters, in which case you'd be getting isolation, though i would be worried with no isolation gap underneath them
Those are definitely bridge rectifiers. The reason why you would put them in, even if it says DC input, is because you don't know what people might plug in. There are AC supplies, DC supplies, centre pin positive, centre pin negative ... and if you plug in the wrong one, there's a good chance you blow every IC on the board. With the rectifier you not only get reverse polarity protection, it also just works, no matter what 12-24 V supply you use. Also, I have never seen DC-DC converters that small and I would even go so far to bet that they don't exist in that package.
I'm *pretty sure* DC-DC doesn't go that small. DC-DC requires a non-linear component (L or C) of a certain size to function. You could make the controller for a buck and/or boost controller that small, but not the passives. That and the form factor and the topology is a dead match for bridge rectifier. (If that was a DC-DC jobby capable of the required power, there wouldn't be a buck regulator and/or linear reg behind it). The schematic was probably lifted straight from an actually isolated design used with two transformers, and they didn't bother to respin it as a fully non-isolated design.
Jasper Janssen fair enough that makes sense, though with the amount of space in the case they could have easily extended the board out a little bit and actually used dc-dc to easily get isolation
Well, yes, but that would cost _money_. Now to be fair: they could have saved a fair amount of the BoM cost of this thing by making it fully non-isolated - drop the two separate power supplies to one, drop the opto - but I don't know, maybe this much isolation is still useful in their intended use case even if it's not *fully* isolated. And maybe the 9 rs485 chips are so much more expensive than an opto, a 78L05, and some passives that it doesn't really matter that much and they just went with a circuit design that was known good from the inside of a more expensive twin-transformer larger unit...
Looks fine to me clive, i know nothing about the serial data of RS485, is it a one way system that addresses a light then sends control data ? is it +/- 5 volt ??
I know next to bugger all about dmx, if its simple serial like the RS232 days then its rather old fashoned, although it would be reliable :-). RS232 was +/- 25v but it would accept much lower voltages. Dont know about dmx standards, eather +/- 5 or 3.3v perhaps?
Full implementation RS485 is a bidirectional differential protocol with the original ANSI standard using +5V and -5V. RS232 is single ended and the original ANSi standard used +12V and -12V. Differential signals are inherently more noise immune than single ended. DMX uses a sub-set of RS485 as most nodes are receive only and only the master node transmits (the lighting desk). So you don't need data collision detection or any of that sort of thing. DMX is in effect a data protocol that in theory could be transmitted over any type of bus, but the industry standard is RS485. It uses data packets that contain the address and then the data to be written to that address.
There's not normally packets that contain an address, just 512 bytes of data. If you want to control more than 512 levels then you use another universe on the lighting desk. The first byte of the DMX protocol is a command byte, but normal practice is for this to be set to "0" and fixtures don't listen to this byte.
Is 3 pin XLR taken over from 5 pin these days? I havent touched DMX in years and back then 5 pin was the standard but 3 pin was common on cheaper hardware and some inbetween had both, I remember 3-pin was not recommended in case a musican takes the good 3-pin data cable for their guitar or plugs the DMX output into their guitar amp...
In fact more expensive lighting uses other standards too like ai-net so you would drop dmx control anyway as it's pretty old and riddled with problems.
the 3pin XLR sockets are cheaper than the 5 pin counterparts and most of the lighting bought these days is low end. Other Manufactures don't use use the two return communication channels (pins 4&5) and thus opt for the 3 pin connector. one of the benefits of using 3 pin is that you can use balanced audio cable to connect lights. This is handy because you can run DMX through a spare channel on an audio snake/multicore to get your DMX universe/s to the stage. Most stuff that you'll see with production companies will be the more expensive fixtures that have 5 pin XLR sockets. They will also use DMX cable that has the correct impedance level - as audio cable is not a perfect match and using it can cause some problems with larger chains of lights.
Still.. I don't miss the huge wall rheostats of the old days that used to smell like an electric fire and used to get old and cause interesting lighting effects on their own accord. So dmx definitely wins.
Answering my own question, but looking at the eBay ads: almost certainly intended to be powered by the same 12vdc or 24vdc supplies being used to power the RGB led strips this will be used with.
So every one of the 512 channels can make a light do something else (at the same moment). Does it mean every one of the 8 outputs just copies the same 512 channels ?
Yes. The controller (lighting desk, pc hardware interface, whatevs) merely sends out data frames with one start byte, then (up to) 512 data bytes each containing a value from 0-255, and then repeats. So if you set your RGB led strip to be channel 500-503, the lighting desk is going to send a start byte, then 500 bytes of 0 for channel 0-499, and then your four desired bytes, which the lighting fixture can interpret however it wants. Traditionally, 0-255 maps onto 0-100% of a dimmer channel, but sometimes it maps onto 0-360 degrees of a moving head direction, or onto one of eight gobo slots, or a color, or.. Etc. And per DMX universe, all that is happening is that there is one sender which is transmitting those 512 channels of one byte each, and there are any number of receivers which are taking any number of those channels and interpreting them as whatever. Hence why a subtly-off data transmission is such a problem.
Why not 5 pin? I cannot find 5pin splitters for a reasonable price ANYWHERE. The Dove systems 4 channel dimmer boxes that we rig would be the most applicable for needing splitters and those ARE 5 PIN. I don't want to risk a loss of bandwidth. It would be fine for LED's but... Damn it my dimmer boxes need signal too. Anywhere we can save money is useful.
the extra 2 pins shouldn't be used then, why not just get a 5pin xlr -> 3 pin converter? I can't see any way that would lead to a loss of bandwidth (although i'm not a secure source for that, please correct me if i'm wrong!)
Board seems nice, but the mechanical design sucks. I would have had the clot plus going straight to the pcb. One nice thing about the plugs on leads is that you don't need to worry about the rare chance of cracking the board.
I don't know, considering how rough those units are handled at events, being plugged in and out every time. I would be far to worried about cracked solder joints. While your 'plugs straight to pcb'-design is cleaner and more elegant, I don't think it's mechanically better.
Does DMX require termination seeing as it's 485? Does this sit the same at the end device in the multidrop configuration? Is it the same nominal 120R value?
"ignore it until problems occur" can also be applied to "mic cable will be fine". :) I'm an audio guy and I'd love to see more videos on live production gear and industrial power.
Does anyone else find Clive's videos relaxing? I like to chill with a drink and watch his long videos even though I know nothing about electronics. I love his sense of humor and the weird things he shows off though.
Yep, I'm teaching myself electronics and originally started watching Clive's videos to learn stuff. Now I re-watch his videos to chill out. They are better than a lot of the repeats we get on UK TV.
Glad I'm not the only one who loves his videos yet has a very small knowledge base of electronics :)
yes and informative :)
Yes, I've disappointed myself multiple times by falling asleep listening to Clive.
I wrote this before - I find Clive's wit and mellow Scottish accent very soothing. I use it as an antidote for Dave (from EEVblog), who has an aggressive Australian accent and an annoying manner of speech :) For me the prescribed dosage is 3 Clives per one Dave :-D
Hi Clive! I'm really interested in lighting stuff, and I'm sure others would really love it too if you did more lighting equipment breakdowns like this.
Surprisingly good quality inside, would be pretty easy to suck off that second bridge rectifier and add another dc in jack to make it fully isolated.
Those 2 rectifiers will separate the ground loop provided that the voltage differential is less than the input voltage. So, it doesn't make it safe against an exploded transformer, but it will (almost) decouple the 50Hz hum.
"That's tacky" - Unintentional pun of the year award goes to Clive... :P
I still find DMX to be a mysterious thing, volunteering at an amdram small theatre & working the lights it was all old transformers, rubber cabling, & a mostly analogue desk (did have basic electronic functions like an auto-fade so you could drop the lights quickly on the board, but they'd fade out slowly, that was about it!), then they changed to DMX to upgrade it all, new programmable desk (so program in the scenes lighting & press a button during the performance to change scene, no fun!), LED & halogen lighting, new cabling that I wasn't to touch, it lost its appeal to me, I liked the old equipment, playing sparky cable roulette there was fun when moving lights about (fully against all H&S regs I'm sure) to set them up for productions, but oh well, sad thing is the old lights they had there are worth a fortune now cos of people living in studio apartments who buy retro theatrical lighting for that vintage look...
"...when something goes wrong with DMX it's like 'Disco central.'"
I mean, the Reggae thing worked for Snoop Lion -- can you blame DMX for trying to bring disco back?
i guess not... but i can blame him for the atrocious recording quality in a good bit of his music.
Stephen Oliveau lol, fair enough.
I actually have this exact one. Works quite well! Most I've ran with it is four lines out with around forty various lights in total.
Just wanted to say thanks for making some of your PCB's available online, got the snowdrops and LED flower PCB's in the mail today, time to track down a suitable power supply and make things!
Surprisingly well made circuit board and it wouldn't be much of a problem to just desolder the bridge rectifiers and feed the two circuits with different power supplies to complete the isolation.
Just ran one of these for a week long gig in the desert, worked a treat :)
I enjoy these videos way more than I should.
Damn, Clive, you're really booming! It feels like just a month ago you had ~80K subs, and now you're at 140.
Good morning, Clive.
Love to see a video up in the wee hours, but you have a song about that, don't you? lol
2 o'clock in the morning...
It's not 2 yet, Central Timer
Now it's almost 3 :D
he plans his videos so Americans have their Clive meal during their evenings :D
not many Mux and Demux videos around. Applied for a network engineer job a while ago and looked into it all. Interesting stuff.
Missile guidance systems and Seeker heads are very interesting too.
Also, at that price, I'd buy the unit merely for the box fitted with all of the XLR outputs as a stage patch box.
Screening?
well this video, and the mention of getting a quality power supply probably answers the question as to why my Thomann and Strand branded DMX buffers/isolators have 240volt inlets, with the PSU inside, thus preventing it being powered by a bad external PSU.
Mr. Clive. You need to get yourself a Post Office box, a 'mail bag' upload schedule. I got, literally, a metric tw*t load of electronic doodads you'd just go nuts for. Disassemble to your heart's content.
If it's got AC going in, and 2 separate rectifiers my guess is that that at some point in the past there was meant to be an isolation transformer in there.
That photo quality was so good I thought I was looking at a large PCB until you drew on it ha
Curious unit. First clue it's not exactly high-end is that it's doing DMX over 3pin XLR connectors, not the usual 5pin.
As to the power isolation; it might be quite easy to fix that by the addition of any of those 5V DC isolator modules made by Murata et.al. You could easily fit one of those inside the case and feed its (isolated) 5V output to the DMX input side. Whenever I do DMX that's usually the power isolation I go for.
The Problem is that all the 8-output DMX connecters are Junk the 3-pins sockets are not soldered to the back of the connector Luckily for me I found one in the DMX cable connector & I found that the Dmx Sockets are two pieces & they have a Sleeve (Socket) inside the connecter & they are just a VERY loose press fit to the back of the connector & Most Pins, Sockets are one solid piece & this is a very strange design & Wow! this being a Very Loose connector could cause all kinds of problems I even cut the connecter apart to verified it! so I replaced all 8 of the output connector & it works Great now
Neutrik??? (FTW!)
I Bought a bunch from E-bay "3-Pin XLR Jack Panel Mount Connector" it better to pick out the ones that are the same Diameter of the DMX unit holes the last ones I bought were to big so I had to drill out the hole
Better to pick one that fit the Hole or you will have to make the Hole Bigger
I would LOVE to see a full laboratory test using all of the kit.
Well, it doesn't look like it would play well with RDM. But I suppose Christmas tree lights and LEDs for use in architectural lighting probably have never heard of RDM. So as a simple buffer in a small setup it will probably work fine.
It's likely this was intended for luminaries that are running on 2-prong isolated wall warts, so it may be that the only real system ground will be at the controller, if that. Since this thing would probably be at the controller too (so you can do a star network) it may never see a ground differential between any of the outputs.
If that board was glued in, methylated spirits (denatured alcohol) works really well for removing hot glue. No idea how it works, but just by putting a little on so it gets drawn in and under the blop of glue and it comes right off after about 30 seconds.
The proper way to isolate the power supplies would be transformer coupled DC-DC converters e.g. a TRACO unit or one made from discrete parts. But that would likely push the price up. I may be able to send you the PCB from an industrial fully isolated RS485 converter (KD485) but it may have to be a faulty unit, I usually repair them but it's not always worth it.
Love the pro lighting videos!
I'm a musician among other things. I've had several DMX buffers which gave me nothing but headaches. Now I know why... That said I've recently gone to a wireless system. I don't know how my system would fare in a large installation because I don't know the actual range of my transceivers. I use a Chauvet WDMX wireless transmitter. and the corresponding Chauvet D-FI Hub wireless DMX light transceiver to control the lights directly. Now the manufacturer says that the transmitter has a range of around 500 feet. I've never tested them at that range as I don't usually position them anywhere off stage. I'd be curious about your thoughts as they are rather expensive being approximately $430 for the transmitter and around $100 for the receivers.
I've been using this for ages, works well! Thanks for the video
Rapid Electronics and RS Components are trade only and are not available to the General Public. In Ireland we had Peat's of Parnell Street for components and hifi. They have closed their store in Parnell Street and now THEY are trade only.
I'm surprised you didn't comment on the fact they used 3-pin XLRs instead of the more common 5-pin. (I know, there's a fair amount of lights these days that come with 3-pin connectors, but they're not all wired the same. Much safer IMO to use 5-pin everywhere and use an adapter that comes with each instrument to go down to the right pinout for that instrument.)
The point of three pin is that it's cheaper and the cables are cheaper, so it seems unlikely that the majority of the fixtures that use it would come with an adapter to five pin. I mean, a given shop could do that as a matter of course (but it's easier just to replace the XLR outs), but I don't think it's normal.
+Jasper Janssen Cables are not actually cheaper. Sometimes people cheat and use microphone cables for DMX, but because they're not twisted correctly, they cause similar hard-to-diagnose issues with flickering/disco-style effects due to interference. Using 5-pin cables is a great way to help ensure you're actually using a DMX cable.
Quentin Smith like I said, three pin XLR cables are cheaper, because you can easily use crappy mic cables instead of proper 120 ohm shielded twisted pair. Plus proper Dmx cables actually connect both pairs even though only one is used, which means you need twice as many center conductors.
Plus the plugs and sockets actually are significantly cheaper on three pin than on five, because they're used on audio runs in great volume.
If you run out of items, tearing down an inkjet cartridge or testing those refilling kits would make for some good viewing.
Don't drink the ink though!
It may make his poop spangly
They work a lot better after I fixed them all by replacing all the 8 DMX output connecters w New ones it was a Lot of work but worth it & still a good Deal,,,(I use a Bunch of Them which makes setup for live shows quicker & less cable runs and in Parallel)
Thanks for posting!
I really like the explanation, and now I’ll buy this dmx splitter
I have one of these and it works well. I just wish it had a power and dmx status light on it for diagnostics.
Hi Clive
Could you do a video on how DMX lighting systems work please ?
would make a very interesting subject
agreed
Would love to see a large rig on a dodgy signal. My rig only has 13 effects on a DMX network and I can confirm that berserk is no exaggeration with only that many.
There is so much space in the case, you could easily mount a secound power input, break the traces of one of the supplies on the board and solder a pair of wires to the second input.
Excuse the potentially stupid question... if its already a DC input supply whats the need for the bridge rectifiers?
polarity doesn't matter
@@rshperformance4127 I noticed you find that on many lighting or audio related equipment, I wonder why...
I purchased a beamZ S2000 smoke machine a few days ago, it is a beast, has LED lighting, fires smoke about 15-20ft in air and is DMX controllable :o
It isolates the signal from the desk from the lights, so if the lights backfed voltage for whatever reason surely the desk would be protected?
That's a nice little project-box. is it available as a non-drilled blank, I wonder.
Banggood has similar for about £5.
yeah I'd like to know this too
So, solder in another power input directly to one of the bridge rectifiers and you're golden? Seems like a really good alternative for temporary installations.
Most serious light/sound/stage companies usually buy proper DMX splitters from Martin, etc. You usually don't want to gamble on neither the power supply or the actual DMX splitter itself :P
Although this should work, the proper DMX standard calls for a 5-pin connector. The reason things like this get around this fact is that 2 pins are for future use and not currently used.
The other two pins were for a second data pair.
Hm, perhaps they got a young graduate (or whatever they have in China) to design it, and he did it by the book, or by the data sheet. Where the data sheet showed 2 power inputs, he just commoned them, and was pleased to see it worked.
If you needed isolation it'd just be a matter of desoldering one of the rectifiers right? Ideally the one feeding the input circuitry. Then as a bonus you could wire in a lower-voltage DC supply so the 78L05 wouldn't be working so hard.
I'm surprised at how nice it is, I was half suspecting a load of resistors and nowt else, maybe a couple of transistors or an opamp or something to drive the outputs all paralleled together. This is pretty much textbook, literally I think.
Based on your description should I treat this product more like a hub/splitter? Meaning, a convenient way to install cable by home-running vs daisy chain. Lastly, should each of the 8 outputs be terminated with a resistor at end of line?
Yes, each run should be terminated with a 120 ohm resistor.
3:26 - glue is tacky you say? hmmm... ya could be. ;-)
Glad I'm not the only one.
The problem was it was still tacky that long after assembly.
"pun intended" Haha
Hi Clive, I hope you don't mind the slightly off-topic question, but you seem like the best person to ask. I'm planning on installing some home automation gear to control my upstairs lights. I want to use dmx dimmer packs, the type with cable terminations, opposed to lamp sockets. Each channel will control a room's lighting. I want to power each pack from the radial circuit for the upstairs lighting (as this will no longer be used, as the packs will distribute power). Do you reckon I'd need another DB secondary to my main consumer unit, with an RCD for each dimmer pack? Thanks :)
You could power a multi-way dimmer rack from a single original lighting circuit breaker. I tend to recommend traditional wiring if possible as specialist wiring can make life difficult in the future for "ordinary" people when the control system fails.
bigclivedotcom interesting. Thanks! Keep up the great videos :)
Full isolation is just an illusion. All DMX equipments have a ground connection that ties one to another indipendently by the dmx cable. The point is that dmx cable is balanced and the opto isolator led sees the voltage difference between dmx pin 2 and 3 with absolutely no reference to ground or earth. It's like pseudo-balance in audio cables (ex. Shure radio mics do it). Doing so it can cancel common mode interference and ground loop problems.
The primary benefit of isolation is when a rig spans several power sources. It avoids issues with ground differences.
Noob question: do you have to have some kind of special power supplies if you were to make this fully isolated if you were to disconnect the rectifiers from each other, or would any two supplies with their own transformers, rectifiers and smoothing caps work? i guess capacitive droppers are out of the question as they are actually referenced to the mains they are connected to
if the grounds of the two supplies are not tied together then it should be isolated well enough.
given it deals with digital data I would expect to see a capacitor right at the power and ground leads of each chip.
There can be significant ground voltage differences between parts of large arena's particularly if separate substations or generators feed each section. So for proper isolation it would need to be able to deal with tens of volts of ground differential or more.
+bigclivedotcom true.
+bigclivedotcom So doing it properly means running both data and power to the buffer receiver from the sending end?
Does that make both sections isolated by 4x (2x per rectifier)diode voltage drops?
No. Just providing two separate power supplies at the unit. Most actual isolators have two transformers inside them to provide full mains voltage separation between input and outputs.
I have one of these. Works pretty decent.
Wow, that box is identical to a project box I bought off Amazon recently. It's really telling that they used hot glue instead of the mounting posts.
Those connectors look like the ones in 3 pin computer fans, which use these colors. I expect that due to economies of scale, that particular color arrangement is the cheapest.
here in Belgium red was commonly used in the old days for ground wire.
A quick question: do you get more money from UA-cam if we watch the whole advert?
yes and i think he gets even more if u click the ad as well
+M3MES Well you can support this man by patreon its easier
Don't randomly click on ads thinking it'll help out. It often gets counted as invalid clicks and can end up getting monetisation disabled.
I haven't actually a clue about how the adverts are processed. I choose the pre-roll skippable adverts because it gets them out the way before the video.
I believe the advertiser only pays if you watch 30 seconds or more before skipping. (or the whole ad if it's 30 seconds or less).
They're using lipo battery cables balance cables I've seen the red, black, yellow like that on ebay
Quite an interesting device. So it basically just amplifies and repeats the same signal. I was thinking it would work more like a network switch, where it could be accessed and it would assign subaddresses to things plugged into it. Didn't know DMX was such a simple standard. Also, is DMX one way, or two way?
One question @ 4:25. Why would ground be Yellow. Green or Brown would be ground if anything. Black if the power supply is ground referenced. Yellow is almost always +12VDC on logic stuff, some sort of signal wire or in the case of AC, it's hot.
The UK earth/ground wire is a green and yellow striped wire. Plain DMX is a very simple standard, but you also get a modern version called RDM that can communicate both ways and also allow the assigning of addresses to lights remotely.
bigclivedotcom
Makes a lot more sense now why that one power supply of mine was colored in what I thought was very nonstandard. Wired hot to ground the first time around and that wasn't very nice when I went to switch it off and unplug it see what was wrong. A bit tingly to say the least.
I do think I read up on those colors afterwords but I appear to have forgotten once again.
Quite interesting about the different types of DMX, might read up on that a bit.
Thanks for the info.
Yes, DMX512 is a simple protocol indeed, which is great since you can use the cheapest microcontrollers to decode it, meaning cheaper stage lightning. It also delivers its data deterministically, i.e. you can be sure that all 512 channels are updated at least 44 times each second (which happens to be just enough for our eyes not to perceive flicker). And should a bit error occur, it will be visible but at least corrected immediately.
More modern protocols have much higher throughput, more channels, bidirectionality etc, but lack some of these basic features.
Just a question, are the outputs of those bridge rectifiers commoned in any way or are they both isolated from each other ?
If they are isolated the cct may well be pefect without using 2 external supplies.
Ground differences are ALWAYS present. We cannot avoid them. Power cables act as transformers that induce currents to ground prong so you cannot eliminate ground voltages between grounded electric equipments. Eliminate grounds connections means serious electrocution danger. (There is a good text if you like, easy to read "UNDERSTANDING, FINDING, & ELIMINATING GROUND LOOPS IN AUDIO & VIDEO SYSTEMS" written by Bill Whitlock, you can find on Jensen transformers site).-- In this case we try to feed a clean DMX (or audio) signal to the equipments. The opto isolator at the input is a good way to RECEIVE a clean dmx signal using the pseudo balanced (or fully balanced if the dmx controller out is fully balanced) cable. A star connection to different dmx equipment (as is this splitter) always create ground loops because connects together the equipments grounds at the outputs of the splitter via dmx cables. The only way to not connect equipment grounds togheter shoud be an opto isolator at the input of each MAX485 and a separate (not grounded) power supply for each of them. Or one only power supply and a transformer on each output. Obviuosly these are expensive methods. Fortunately DMX is not audio signal and is inherently protected by his "high" voltage (compared to an audio signal) and by balanced cables. --
I use this splitter in a theater to receive the dmx signal after 50 mt of dmx cable and feed 2 different lines of dmx fixtures. It regenerates dmx signal and avoids overload dmx connection splitting it with different buffers on the outputs. For the price is more than i expected.
Great video thank you was thinking of getting one. As I find dmxing easier this way than daisy chaining
lol "I'm going to have to pull this board out of here", as if we didn't already know it was inevitable. ;)
Not sure why people are really wondering too much about the isolation of power supplies on such a cheap unit not intended for professional use.
Strictly speaking it doesn't even conform to the DMX standard as its got 3 pin connectors when the standard specifies 5 pin connectors.
$0.02
Most lights don't conform either. It's a bloody pigs ear of a mess covered in junk!
"...glued in? Well that that's a bit tacky."
LoL I see what you did there ;-)
Bridge rectifier... on DC? I'm not an electrical engineer of any sorts, I don't know much about this stuff... but why do you need a bridge rectifier for DC? Unless it's for making sure the input polarity is correct, like + is + and - is - if you use the wrong power supply?
Yup. Reverse polarity protection. And that's about it.
theLuigiFan0007 Ah cool, thanks
The bridge rectifiers have some merit since they let the lighting desk and lighting fixture ground voltages diverge by 12 V (when powered on) without creating a ground loop. Replace the buck converter with a flyback or other isolated converter, and you would have a real isolation barrier for almost the same price. Still not very useful though, since you want all 8 outputs to be isolated from each other too.
I find it interesting that it seems to use Cannon Plugs to plug the light control cables in since that's what microphones use. Also, what are those little white three-pin connectors called that plug into the circuit board? I see those all over the place, mainly on the little rechargeable battery packs that those hand-crank emergency radios use.
Fixy Clary it's using the standard sockets that DMX lighting uses, to provide compatibility. There would be no point using anything else.
Can anyone (+bigclvedotcom) explain the point of the bridge rectifiers? The case suggests that the power supply is DC - I'm confused.
I think the PCB is probably multi use. At the very least they will provide automatic polarity correction on the input.
+bigclivedotcom Thanks. Makes sense.
I've seen some gear using a supplied external PSU with an AC output
(higher than 12V) so rectification is needed on the board inside the gear.
I can't recall if using a DC PSU will still work the gear properly.....
Telephone equipment (UK's BT) often used PSU's outputting AC....
I fall asleep to this guys voice ~
I do to, from time to time. Soothing.
Seems like you could quire easily mod this unit to separate the power supply for the input chip, right?
Maybe adding a quick sketch of the schematic - either on paper or a white board - would give some clarity to your reviews?
Unless the switching supply's output is isolated, then both supplies aren't properly separated.
Have a good Tynwald day Clive.
been tearing my har out troubleshooting randm flashing/twitching of lights in a venue. been fine for a while. would come in and it would be fine, then other days it happenns.
im not a lighting tech, recently discovered that dmx cabling is different to audio xlrs, so thats 1 issue, then found out that after certain amount of fixtures need a bufffer.
we have 16 movers, 14 led pars...
i never installed the cabling, did give instructions but it wasnt followed, the pars got installed first and wired up, then movers were added, pretty sure instead of goinng from first closest light and going round, they just wennt from last light.... cabling far too long
Would you recommend to buy this for a little theatre scene?
Even the QTX DMX-D8 for about 64 UKP is fully isolated...
Just looking at the DMX buffer before it's opened, I wouldn't even touch it. When running shows, you want as close to 100% reliability as possible and this... Well... It looks like you'd be better ff using a Y-split.
Yey, 1000'th like! I guess it wouldn't be too hard to add another power input, considering how nice that box is.
so if had the correct XLR plugs on it (5 pin not 3 as specified within the DMX standard) would it be compliant with the standard?
Quick question, are you sure those are bridge rectifiers? Cause it says the input is DC so why would they need a rectifier there? If I had to guess they'd be small dc-dc converters, in which case you'd be getting isolation, though i would be worried with no isolation gap underneath them
Those are definitely bridge rectifiers. The reason why you would put them in, even if it says DC input, is because you don't know what people might plug in. There are AC supplies, DC supplies, centre pin positive, centre pin negative ... and if you plug in the wrong one, there's a good chance you blow every IC on the board. With the rectifier you not only get reverse polarity protection, it also just works, no matter what 12-24 V supply you use.
Also, I have never seen DC-DC converters that small and I would even go so far to bet that they don't exist in that package.
I'm *pretty sure* DC-DC doesn't go that small. DC-DC requires a non-linear component (L or C) of a certain size to function. You could make the controller for a buck and/or boost controller that small, but not the passives.
That and the form factor and the topology is a dead match for bridge rectifier. (If that was a DC-DC jobby capable of the required power, there wouldn't be a buck regulator and/or linear reg behind it).
The schematic was probably lifted straight from an actually isolated design used with two transformers, and they didn't bother to respin it as a fully non-isolated design.
Jasper Janssen fair enough that makes sense, though with the amount of space in the case they could have easily extended the board out a little bit and actually used dc-dc to easily get isolation
Well, yes, but that would cost _money_.
Now to be fair: they could have saved a fair amount of the BoM cost of this thing by making it fully non-isolated - drop the two separate power supplies to one, drop the opto - but I don't know, maybe this much isolation is still useful in their intended use case even if it's not *fully* isolated. And maybe the 9 rs485 chips are so much more expensive than an opto, a 78L05, and some passives that it doesn't really matter that much and they just went with a circuit design that was known good from the inside of a more expensive twin-transformer larger unit...
If the inductor of te buck converter is a transformer the two circuits can be Isolated. But that doesn't seem to be the case here.
Looks fine to me clive, i know nothing about the serial data of RS485, is it a one way system that addresses a light then sends control data ? is it +/- 5 volt ??
can't remember the exact voltage but yeah, it's differential, +/-
I know next to bugger all about dmx, if its simple serial like the RS232 days then its rather old fashoned, although it would be reliable :-).
RS232 was +/- 25v but it would accept much lower voltages.
Dont know about dmx standards, eather +/- 5 or 3.3v perhaps?
Full implementation RS485 is a bidirectional differential protocol with the original ANSI standard using +5V and -5V. RS232 is single ended and the original ANSi standard used +12V and -12V. Differential signals are inherently more noise immune than single ended. DMX uses a sub-set of RS485 as most nodes are receive only and only the master node transmits (the lighting desk). So you don't need data collision detection or any of that sort of thing. DMX is in effect a data protocol that in theory could be transmitted over any type of bus, but the industry standard is RS485. It uses data packets that contain the address and then the data to be written to that address.
Yep single direction system, with target and data frames, sounds simple enough ;-)
There's not normally packets that contain an address, just 512 bytes of data. If you want to control more than 512 levels then you use another universe on the lighting desk. The first byte of the DMX protocol is a command byte, but normal practice is for this to be set to "0" and fixtures don't listen to this byte.
Is 3 pin XLR taken over from 5 pin these days? I havent touched DMX in years and back then 5 pin was the standard but 3 pin was common on cheaper hardware and some inbetween had both, I remember 3-pin was not recommended in case a musican takes the good 3-pin data cable for their guitar or plugs the DMX output into their guitar amp...
You only find 5 pin on professional fixtures. 3 pin is still the standard on cheaper and mid price lighting.
In fact more expensive lighting uses other standards too like ai-net so you would drop dmx control anyway as it's pretty old and riddled with problems.
the 3pin XLR sockets are cheaper than the 5 pin counterparts and most of the lighting bought these days is low end. Other Manufactures don't use use the two return communication channels (pins 4&5) and thus opt for the 3 pin connector.
one of the benefits of using 3 pin is that you can use balanced audio cable to connect lights. This is handy because you can run DMX through a spare channel on an audio snake/multicore to get your DMX universe/s to the stage.
Most stuff that you'll see with production companies will be the more expensive fixtures that have 5 pin XLR sockets. They will also use DMX cable that has the correct impedance level - as audio cable is not a perfect match and using it can cause some problems with larger chains of lights.
"Is this circuit board glued in? Well that's a bit tacky!" -- Pun Master 5000 :)
Haha yes, I remember "cool lighting effects" comments from the cast whilst giving them the side eyes and trying to fault find a bad dmx rig
Still.. I don't miss the huge wall rheostats of the old days that used to smell like an electric fire and used to get old and cause interesting lighting effects on their own accord. So dmx definitely wins.
Just thinking about it in my head, wouldn't the 2 bridge rectifiers give you "sort of" isolation between the 2 separate DMX grounds?
It would probably block very low voltage differentials like 1 or 2V.
I need a Big Clive T-shirt that says "thats Quite Interesting, Thats quite interesting Indeed"
each output should be optically isolated from the other
Would the supply have been a DC type, or maybe just an AC transformer plug pack?
Answering my own question, but looking at the eBay ads: almost certainly intended to be powered by the same 12vdc or 24vdc supplies being used to power the RGB led strips this will be used with.
So every one of the 512 channels can make a light do something else (at the same moment). Does it mean every one of the 8 outputs just copies the same 512 channels ?
Yes. The controller (lighting desk, pc hardware interface, whatevs) merely sends out data frames with one start byte, then (up to) 512 data bytes each containing a value from 0-255, and then repeats. So if you set your RGB led strip to be channel 500-503, the lighting desk is going to send a start byte, then 500 bytes of 0 for channel 0-499, and then your four desired bytes, which the lighting fixture can interpret however it wants. Traditionally, 0-255 maps onto 0-100% of a dimmer channel, but sometimes it maps onto 0-360 degrees of a moving head direction, or onto one of eight gobo slots, or a color, or.. Etc.
And per DMX universe, all that is happening is that there is one sender which is transmitting those 512 channels of one byte each, and there are any number of receivers which are taking any number of those channels and interpreting them as whatever. Hence why a subtly-off data transmission is such a problem.
I have often no idea what you're talking about.. but somehow I still find it interesting.
Why not 5 pin? I cannot find 5pin splitters for a reasonable price ANYWHERE. The Dove systems 4 channel dimmer boxes that we rig would be the most applicable for needing splitters and those ARE 5 PIN. I don't want to risk a loss of bandwidth. It would be fine for LED's but... Damn it my dimmer boxes need signal too. Anywhere we can save money is useful.
Are you driving 2 universes through each cable?
Pownyan lol no we use dove dimmers that take 5pin
the extra 2 pins shouldn't be used then, why not just get a 5pin xlr -> 3 pin converter? I can't see any way that would lead to a loss of bandwidth (although i'm not a secure source for that, please correct me if i'm wrong!)
3:30 the puns are real.
Board seems nice, but the mechanical design sucks. I would have had the clot plus going straight to the pcb.
One nice thing about the plugs on leads is that you don't need to worry about the rare chance of cracking the board.
I don't know, considering how rough those units are handled at events, being plugged in and out every time. I would be far to worried about cracked solder joints.
While your 'plugs straight to pcb'-design is cleaner and more elegant, I don't think it's mechanically better.
It's OK when the connectors are properly secured to the panel, the cheaper stuff where it just pokes through a hole is a pain.
man, I've been dealing with cracked solder and ripped PCB lanes way too often to say it would be better to solder the PCB straight to the plugs
Ah DMX, my arch nemesis :p
Would it be hard to split the power into two supplies so it is isolated?
Does DMX require termination seeing as it's 485? Does this sit the same at the end device in the multidrop configuration? Is it the same nominal 120R value?
Yes. But many just ignore it until problems occur.
"ignore it until problems occur" can also be applied to "mic cable will be fine". :)
I'm an audio guy and I'd love to see more videos on live production gear and industrial power.
3:27 - Glued in... Tacky... I see what you did there!
Clever guy love your vids Clive
hi clive good day, can i use a 18.5 VDC 3 amp adaptor on this unit?
Why does it need a bridge rectifier if you supply DC?