Japanese 100V guitar effects pedal power supply in Canada - Page 1
Forum section: electronics / beginners

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 07:59:16 pm
content: Hi all!Thanks for accepting me. I recently bought a used Voodoo Lab Pedal Power 2 Plus power supply, intended to power (mainly 9v) guitar effects. The supply is made in the US, but this particular model, I belatedly discovered, was manufactured for the Japanese market. As a result, it is intended to run on 100V, and I'm in Canada. I've emailed the manufacturer, and they said it's not okay to use it, since it would run hot and likely fail prematurely. I got it for a decent price, so I'm debating whether to keep it — but only if there is no safety issues (fires? melting cables?) or any potential damage to my equipment downstream from the unit, i.e., effects pedals, cables, and amp, since the pedals are in an effects loop.So I need to know: will there be any downside to using this power supply aside from the damage that may be inflicted on the unit itself?Here's as much as I can tell you about it:Voodoo Lab Pedal Power 2 Plus100V 50/60Hz (Japanese model)Toroidal transformer inside, linear (I think)Basically, it takes power from the wall outlet and trasnfers it to 8 separate isolated DC outputs.I'll try to answer any questions as they arise, but I would love to hear your thoughts on this!Thanks!

author: Andy Chee
author_rank: Super Contributor
timestamp: November 10, 2024, 08:32:09 pm
content: No safety issues, but yes, premature failure is a potential outcome. And with regulator failure, could also potentially see damage to downstream equipment.Given that the same model is sold for different power supply markets i.e. 100, 120, 240, it might be possible that the voltage change is accomplished with a change in primary winding tap. Unfortunately the manual lacks a schematic diagram so it's unknown if this is even possible unless you open up the case.

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 08:38:48 pm
content: Thanks for the response, Andy.As a complete newbie… I assume that the regulator would manage the current that is fed to the DC outs, yes? If so, then if it fails, the overvoltage could make its way through the unit to impact the pedals in the chain?Sorry for being a complete twit when it comes to this stuff.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 10, 2024, 09:01:38 pm
content: Correct.The toroidal transformer likely steps down the 100VAC to, maybe 10VAC. The regulator (and bridge rectifier) then converts that to 9VDC for your equipment.If you put 120VAC into the toroidal transformer, the stepped down voltage will be 12VAC, not 10VAC. This larger voltage will cause the regulator to dissipate more heat, potentially leading to failure, depending on heatsink and cooling design.And when regulator failure occurs, the output will be maybe 10-12V, not 9V.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 10, 2024, 09:23:45 pm
content: Quote from: edavid on November 10, 2024, 09:18:36 pmYou're correct. I immediately assumed a simple discrete regulator consisting of just a pass transistor and zener diode.In order for us internet engineers to assess the suitability for 120V operation, the OP needs to obtain a schematic or open the box and take some good photos.

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 09:44:31 pm
content: Thanks for the responses, guys!I don't feel comfortable taking it apar—and I still may be able to return it to the seller—so I looked for gut shots of the PP2+ on the web, and came up with two.Now, these are likely from the 120V model, and not the 100V Japanese version, w2hich is what I have. But hopefully, this will give you an indication of the layout, etc.:FYI, there is a mains input plus a "courtesy outlet" (200 watts) which you can plug additional power into if necessary, for expandability.)

author: Analog Kid
author_rank: Super Contributor
timestamp: November 10, 2024, 09:53:39 pm
content: From what I can see in those photos, the transformer primary only has one winding with no taps. The transformer is sized for the voltage of the market.Any other ideas here from the peanut gallery? How about something like a lighting dimmer using a SCR to reduce the voltage?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: November 10, 2024, 10:54:37 pm
content: 2 cents from the peanut gallery.fyi. That aint no torroidal transformer.Looks like it would have high magnetic leakage. Probably not that suitable for Audio. ie. lots of remnant mains hum.But lots of leakage means bad transformer voltage regulation (more voltage drop) which may help the linear regulators.I would return it if possible.If not possible then open it up and check for over heating. Have different loads eg. No load, 1 single large load, Multiple large loads. Keep watching the temperature without touching the mains voltage.Also check the sticker on the actual transformer.I doubt the saturation would be a problem as the canadian 60hz would lead to less saturation than the japanese 50 hertz. flux being proportional to V/f. so you may have roughly similar peak flux.

author: Benta
author_rank: Super Contributor
timestamp: November 10, 2024, 11:11:35 pm
content: Just use it.You say 100VAC, 50/60Hz. It will run with no problems at all on 120VAC, 60Hz. The higher Canadian frequency (60 Hz) will elevate the primary voltage to 120VAC.

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 11:13:53 pm
content: Benta, to clarify, this is a gut shot from another unit. I haven't cracked mine—but the innards are going to be similar.Mine is definitely a Japanese market model, runn ing at 100V 50/60HZ.

author: Benta
author_rank: Super Contributor
timestamp: November 10, 2024, 11:16:31 pm
content: Sorry modified my post (misinterpreted your photos). The present reply stands.

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 11:20:21 pm
content: Quote from: HackedFridgeMagnet on November 10, 2024, 10:54:37 pmHi, all I'm going from is the manual re: toroidal tranny (see attached, below). Also, it's a really well-regarded pedal power supply, is silent in my setup, and has been the go-to for most musicians' pedalboards for well over a decade.

author: Outtakes7432
author_rank: Contributor
timestamp: November 10, 2024, 11:24:47 pm
content: Quote from: Benta on November 10, 2024, 11:11:35 pmSeriously? That's great! I'd rather not go to the trouble of trying to get the seller to take it back. As I said, it's a good deal, so I'm happy to use it as long as it can't screw up anything downstream from it.Good news!

author: BrianHG
author_rank: Super Contributor
timestamp: November 10, 2024, 11:41:08 pm
content: Quote from: Analog Kid on November 10, 2024, 09:53:39 pmNO. Never for transformers.

author: BrianHG
author_rank: Super Contributor
timestamp: November 10, 2024, 11:47:16 pm
content: Quote from: HackedFridgeMagnet on November 10, 2024, 10:54:37 pmIts an R-Core transformer. Specially designed for lack of leakage between mains and secondary. Used in premium grade audio pre-amp and DAC equipment.EG:https://www.aliexpress.us/w/wholesale-r%2525252dcore-transformer.html?spm=a2g0o.home.search.0

author: Benta
author_rank: Super Contributor
timestamp: November 10, 2024, 11:50:48 pm
content: Quote from: Outtakes7432 on November 10, 2024, 11:24:47 pmYes. It's called the V/f relationship and is valid for classic mains transformers (within limits!). 100VAC/50Hz = 120VAC/60Hz.Issue fixed.Cheers.

author: BrianHG
author_rank: Super Contributor
timestamp: November 10, 2024, 11:53:47 pm
content: If you want, you can make your own 120v to 100v converter using a single mains AC 120v -> 20v...25v AC transformer.Just wire the 120v to the 120v transformer input.Wire one side of the 20.thru.25v output to the hot of the mains 120v.Make an output plug wired to the 120v neutral and the other leg of the 20.thru.25v output side as your new 'hot'.Measure with an AC volt meter. If you see ~145v, then all you have to do is reverse the polarity of the 20.thru.25v secondary side of the transformer. Then the output will be ~100v.This transformer should do:https://www.digikey.com/en/products/detail/hammond-manufacturing/187B20/2360621It will basically subtract 20v from your mains AC wired as I described above.It will handle around 250 watts.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 10, 2024, 11:56:36 pm
content: Quote from: BrianHG on November 10, 2024, 11:41:08 pmYikes. Got singed a bit there.All I can say is that I have done that forbidden thing successfully. Now my transformer wasn't inside a power supply like this: I was simply using a transformer to deliver variable voltage to a heating unit.I know you're not supposed to do this, but I'm not sure exactly why: yes, I know that a SCR will "chop" the waveform, so you no longer have a nice sine wave, but what are the actual results from this if the transformer is driving a power supply like this? i mean, it's not going to catch on fire, is it?I would be interested in details here, if it's not too much of a diversion of this thread.

author: Benta
author_rank: Super Contributor
timestamp: November 10, 2024, 11:59:03 pm
content: Quote from: Analog Kid on November 10, 2024, 11:56:36 pmBetter start a new thread. Highjacking is a no-no.

author: Benta
author_rank: Super Contributor
timestamp: November 11, 2024, 12:01:54 am
content: Quote from: BrianHG on November 10, 2024, 11:53:47 pmWhy bother? As I already said, it's specified for 100V/50Hz, which will make it run exactly the same at 120V/60Hz. Looking at the pictures, the secondary side won't really care about the extra 20% voltage.

author: BrianHG
author_rank: Super Contributor
timestamp: November 11, 2024, 12:04:38 am
content: Quote from: Benta on November 11, 2024, 12:01:54 amFine. I was offering an option if the op really needed it.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 11, 2024, 12:17:19 am
content: Quote from: Analog Kid on November 10, 2024, 11:56:36 pmAn SCR chopper operates on one half of the AC cycle only, resulting in a net DC through the primary winding. This DC will saturate the transformer.OTOH, if you use a triac chopper and operate it on both half AC cycles, there will be no net DC.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 11, 2024, 12:41:09 am
content: Thanks. I'll take this to a new thread.

author: bw2341
author_rank: Regular Contributor
timestamp: November 11, 2024, 02:40:11 am
content: Quote from: Benta on November 11, 2024, 12:01:54 amhttps://voodoolab.com/product/pedal-power-2-plus/I think you may have jumped the gun here. The worry is about too much voltage from the secondary. From the product page, this looks like an all linear regulator design.If so, there is a risk of overheating and premature failure when running the 100V version on 120V.As a personal anecdote that may not apply in this case, I have an ancient Sony Discman portable CD player that was grey market from Japan. It has a 100VAC in 9VDC out iron transformer power adapter. When using it, there is a hotspot on the metal baseplate of the CD player. While it is uncomfortably warm to the touch, it has not failed. The open circuit voltage of the power adapter is 14.6VDC on 122.6VAC in. I haven't opened the CD player to measure the input voltage under load. I don't have an alternative adapter that will fit to see how warm it should be when operating correctly.

author: Outtakes7432
author_rank: Contributor
timestamp: November 11, 2024, 03:47:08 am
content: Original poster, here.I'm actually okay with the possibility that the power supply may fail prematurely. What I'm concerrned about is that if it does fail, that it could take out or adversely affect the pedals (and, however unlikely, the guitar amp itself—the pedals are powered through the effects loop—when and/or if it does).Do you see an issue with it screwing up my downstream electronics? Is there a consensus here?

author: Analog Kid
author_rank: Super Contributor
timestamp: November 11, 2024, 06:22:24 am
content: Quote from: Outtakes7432 on November 11, 2024, 03:47:08 amNot an expert here, and certainly don't want to be in any way responsible for the destruction of your gear.However, you might be able to answer that question yourself.I didn't see anywhere in this thread that you had actually measured the voltage at the power supply outputs. Can you do that? Either with nothing plugged in, or preferably with a dummy load (a resistor across the output).That way you'd know what voltage the things you plug into it will get.Plus you'll get to find out just how warm it gets in operation.A dummy load would be a high-ish value resistor that has a watt rating high enough not to burn out.If you want to do that, people here can tell you how to rig that up if you don't know how.That's what I'd do.

author: Outtakes7432
author_rank: Contributor
timestamp: November 11, 2024, 03:53:06 pm
content: Quote from: Analog Kid on November 11, 2024, 06:22:24 amI THINK I did this correctly; used a barrel to battery snap cable to measure Amperes and Voltage separately.On 10A multimeter setting: 0.15AOn 9V multimeter setting: Betwen 9.12V-9.18VMy wall outlets were bang on 120 V.Does this help? Thanks!

author: Analog Kid
author_rank: Super Contributor
timestamp: November 11, 2024, 07:56:58 pm
content: So 9 volts is the nominal voltage output, correct?If so, then you have no problem at all. 9.18V is 9 volts for all practical purposes.It won't harm your gear.Do others here agree on that?

author: John B
author_rank: Frequent Contributor
timestamp: November 11, 2024, 08:56:39 pm
content: The whole point of a linear power supply for audio is to minimise any noise, so any type of TRIAC chopping of the mains is going to adversely effect that. I don't know why anyone suggests it for anything these days, other than the most brute force applications like heating elements.The pedals in turn should have their own voltage regulators, so I wouldn't be too concerned. The risk to downstream gear is going to be determined on how robust the linear regulators are. While they should be pretty resilient with over temp protection, I'd still like to see something larger than SOIC package regulators.I'm more curious about the advertised 8x isolated outputs. It just looks like a bank of linear regulators, so is it a custom transformer with 8x secondaries?

author: Zero999
author_rank: Super Contributor
timestamp: November 11, 2024, 09:16:04 pm
content: Quote from: Andy Chee on November 11, 2024, 12:17:19 amIt depends on what is meant by SCR chopper. Two SCRs can be used to make a full-wave phase controlled dimmer, which will work fine for a heater, but cause problems for a guitar effects pedal, due to switching noise.Quote from: BrianHG on November 10, 2024, 11:53:47 pmYes that will work. Another option is to use a 120 to 12V transformer connected as an auto-transformer.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 11, 2024, 09:18:28 pm
content: OK, I think we've pretty much ruled out the SCR/triac voltage-reducing scheme here. As the originator of that idea, I'll confess:bad idea. Let's just move on from that, 'k?It looks to me, based on the OP's measurements, that no remedy at all is needed here to safely use this to power his boxes. Does anyone disagree with that?

author: BrianHG
author_rank: Super Contributor
timestamp: November 12, 2024, 02:45:24 am
content: Quote from: Zero999 on November 11, 2024, 09:16:04 pmI thought that was what my example wiring was creating.

author: Circlotron
author_rank: Super Contributor
timestamp: November 12, 2024, 04:22:56 am
content: Quote from: Andy Chee on November 11, 2024, 12:17:19 amThere will be no nett DC only, and if only, the firing point of the triac isidenticalfor both positive and negative half cycles. Many discreet component zero crossing detectors are pretty average in this regard, and can lead to a burned out transformer, hence the old wives' tale that phase control can't be used on a transformer. It can, but you gotta make sure of dead equal volt/seconds above and below zero. But in this particular application, no, because the sharp leading edges of the chopped AC waveform would introduce a lot of noise into the signal path.

author: Zero999
author_rank: Super Contributor
timestamp: November 12, 2024, 11:36:35 am
content: Quote from: Circlotron on November 12, 2024, 04:22:56 amAnyway, a phase controller is no good for audio, because it will result in a nasty buzzing soundQuote from: BrianHG on November 12, 2024, 02:45:24 amNo, you suggested wiring the primary to 120V and the secondary in series, anti-phase, to reduce the voltage. In an auto-transformer configuration, the secondary is wired in series with the primary, in-phase. The mains is applied to the secondary and the output taken from the tap created between the secondary and primary.Both of the above will work just as well as one another. Your idea requires a transfromer with a 20V secondary and mine a 12V secondary.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 12, 2024, 12:11:35 pm
content: Benta is right from the transformer viewpoint. Japan has a weird 50/60Hz split across the country so equipment designed for Japanese market must work reliably at both 100V 50Hz and 100V 60Hz.Now usual problem with running transformers outside original specs is increase in magnetic flux; cheap transformers already operate into saturation, so going further into saturation shows significant steep increase of primary current and as such also more resistive heating in the transformer.But, the flux is actually exactly the same for 100V 50Hz and 120V 60Hz! So just don't run it at 120V 50Hz, and the transformer will be fine.However, this does not account for the increase in output voltage. It's a separate question. Now you will get 20% too high output AC voltage and it depends on the rest of the circuitry if it will handle it. If they use linear regulators, it results in higher power dissipation, more heating.The thing is, if the unit is even halfway decent, it must be designed for normal amount of overvoltage in grid (depends on country but generally around 10%). If you are confident that at your site grid voltage is really 120V most of the time and very rarely exceeded then you are not exceeding the design by 20%, just by 10%... which a decent unit should handle.But combination of high temperature in the summer, plus some grid overvoltage (even if normal - say a lot of solar panels in your neighborhood) could bring the unit over the edge.And without schematics, it's hard to say if the power supply regulates, or if it's the effect pedal which has a regulator. In latter case the extra strain would be put on the pedal. On the other hand in latter case it would be quite easy to put one or two diodes in series to drop the voltage by 0.6 - 1.2 V.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 12, 2024, 06:34:22 pm
content: I think we're running aground into the weeds here, at least from the OP's point of view.After all, they wanted the answer to a basically simple question: will using this power supply roast my effects gear plugged into it?My take on that isno, it's safe to use as-is. This is based on the OP's measurement of the output voltages of the supply, which are just about exactly 9 volts as advertised.So let me ask again: do we agree here that this power supply is safe to use with the OP's gear?If so, problem solved, and no modifications are necessary.

author: Outtakes7432
author_rank: Contributor
timestamp: November 12, 2024, 09:49:09 pm
content: Here's one more detail about the unit. On the back of it, corresponding to the eight DC outputs, are a series of 8 individual dip switches. These can be flipped to change the voltage at each output to accommodate 12V pedals. Also, if you have super high current effects, you can use a doubling cable which looks like it taps into two outlets at once, then channels the power into one power hungry pedal.Just FYI.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 12, 2024, 09:58:23 pm
content: So just to confirm: you wrote that you measured (one? all?) of the outputs, and I believe you reported 9.18 volts.They are rated at 9 volts (without flipping the DIP switch to 12 volts).Therefore, this power supply is safe to use with all your gear, plugged into 120V 60Hz power.Problem solved.Can somebody please confirm this (or not)?BTW, the suggestion of using a SCR or triac on the 120 volt input side has been formally withdrawn by its originator (me), so we really don't need to discuss this any further. OK?

author: Andy Chee
author_rank: Super Contributor
timestamp: November 12, 2024, 10:00:02 pm
content: Quote from: Analog Kid on November 12, 2024, 06:34:22 pmThe OP seems overly paranoid about destroying downstream equipment.As such, if I were to apply the same paranoid sentiment to the analysis of the power supply, I would not use it because it lacks over-voltage protection (at least from the images supplied so far).That said, I am not paranoid and I would personally have no issue with using the power supply as is. In fact, I am so cavalier that I would just use any old wall wart retrieved from e-waste, rather than this!

author: Outtakes7432
author_rank: Contributor
timestamp: November 12, 2024, 10:00:34 pm
content: Yes, exactly. I think I measured 3 outputs. Thay all fell within that range.

author: Outtakes7432
author_rank: Contributor
timestamp: November 12, 2024, 10:04:21 pm
content: The OP seems overly paranoid about destroying downstream equipment.As such, if I were to apply the same paranoid sentiment to the analysis of the power supply, I would not use it because it lacks over-voltage protection (at least from the images supplied so far).That said, I am not paranoid and I would personally have no issue with using the power supply as is. In fact, I am so cavalier that I would just use any old wall wart retrieved from e-waste, rather than this!One person's "paranoid" is another person's "diligent."You've never had a pedalboard, then. You gonna take a bag full of wall warts to a gig? Unreal.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 12, 2024, 10:07:05 pm
content: Quote from: Outtakes7432 on November 12, 2024, 10:04:21 pmI certainly respect that. Why risk damage to a bunch of gear that you no doubt like and that works well for you?I'd say go ahead and start using it. But just to be on the safe side, maybe take your DMM to gigs, and check the power supply from time to time.

author: BrianHG
author_rank: Super Contributor
timestamp: November 13, 2024, 01:33:38 am
content: Just so we are clear, guitar pedals draw less than 1ma. After all, you expect them to operate for months on a single 9v alkaline battery. I don't think a little extra voltage at the regulator input will make more heat with such a light load.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 13, 2024, 01:46:12 am
content: Quote from: Outtakes7432 on November 12, 2024, 10:04:21 pmNope.If I didn't value my equipment, I'd just use a single conventional wallwart, and make up a multi-way Y("wye") octopus adapter.If I did value my equipment, I would look for (or build) a supply with over-voltage protection.

author: bw2341
author_rank: Regular Contributor
timestamp: November 13, 2024, 04:56:06 am
content: Quote from: Outtakes7432 on November 11, 2024, 03:47:08 amI found a blog post that has pictures of the 100V version. Still not detailed enough to determine the part numbers of the linear regulators.http://studiogream.blog.fc2.com/blog-entry-275.htmlEven the classic 78xx series of linear voltage regulators have thermal-overload protection. You can open up the power supply and look up the exact part numbers to check if the regulators have the same feature. If so, the output voltage will fall below the target voltage to keep the temperature in check.This is a safe, temporary failure as decreasing voltage may affect the sound of the gear, but it shouldn't damage anything at all.However, this doesn't cover what will happen if the regulator is physically damaged from wearing out. Failing open with no output voltage is the most likely outcome, but there are no guarantees. It could fail shorted and pass the higher unregulated voltage to the loads.Looking at the pictures, I'm a bit more confident that the power supply would not be stressed too much running at 120VAC. It looks like the transformer has only 8 secondary windings, so it must be burning off 3V extra in the regulators when running normally in 9V vs. 12V mode. So the extra thermal dissipation running at 120VAC may not be too crazy. Maybe 150% watts of heating instead 200% or 300%?

author: Analog Kid
author_rank: Super Contributor
timestamp: November 13, 2024, 05:12:57 am
content: At your next gig, put a drink with ice on top of the power supply and see how long it takes for the ice to melt.

author: Outtakes7432
author_rank: Contributor
timestamp: November 13, 2024, 05:37:10 am
content: Quote from: Analog Kid on November 13, 2024, 05:12:57 amGreat idea. But I'm afraid I'll be too busy before the first set either daisy chaining all my pedals (a bit noisy, but…safety first!) or cobbling together a power supply with robust over-voltage protection, so I can indulge my dangerous and rampant paranoia and thus feel better knowing that my neurotic impulses are assuaged by the comfort derived from creating a robust, unassailable PSU that can run all my electronics faithfully and without mishap.;-)I'm keeping the PP2+ and my tinfoil hat. I'll deal with this.