# "Switching" Power supplies



## allthumbs56 (Jul 24, 2006)

Wondering if anyone has any experience with the newer wall warts like the Godlyke Powerall or the One-spot. They advertise well and claim to be able to handle tons of pedals. One guy I talked to at the local shop thought they messed with some pedals though.

I'm thinking of picking up a One-spot or a Powerall to replace the two Boss PSAs I'm currently using - just to clean up things and leave a bit of room for growth. I've got 11 pedals on my board currently - half of them are for dirt but I also have 3 delays and a PS-5 on there.

Anyone have any thoughts?


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## keto (May 23, 2006)

I have a OneSpot here at home, it's for home use only. I don't remember the specifics, but when I daisy chained 6 or 7 on it, some wouldn't function (it was a while back, couldn't tell you which ones). I wouldn't ever use it as my main power supply on a rig that I was taking out from home. I just bought it as a cheap stop-gap/handy to have around unit for testing 1-2-3 pedals at a time.

I use the much underappreciated Dunlop DC Bricks. I've owned 4 or 5 of them now, over the course of many years, and never had a lick of trouble with them (I had 3 at once, sold a couple off, bought a couple more later). I know they aren't isolated supplies, but I don't get any wierd extraneous noise using 2 of them to power 10-14 pedals on a board. They have 6 spots for 9v and 3 for 18v - I've used them ALL at once at times and, again, not had issues. I'm sure there are pedals that have too much draw for them, but I haven't had that experience.


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## surlybastard (Feb 20, 2011)

I used a 1-spot for years and it's definitely good value for the money but it has some drawbacks (for reference I also tried a Power-all once to see if there was any difference, there wasn't). Since I don't know how you plan to use it I'll give you a few scenarios where I think it's appropriate based on my usage:

Who should buy a 1-spot/Godlyke: Anyone who's a bedroom player with lots of pedals (up to 8) who's going to be playing at low volume exclusively, giggers/jammers with 2-4 low current pedals who play with a fair bit of volume but not a lot of gain. 
Who should *not* buy a 1-spot/Godlyke: Anyone who's gigging/jamming who play with a fair bit of volume or higher and play with substantial amounts of gain.

Let me first say it does depend on what pedals you use, but the last time I used a 1-spot my board was something like: Wah, TS9, OCD, Boss TU-3, Sovtek Black Russian Muff, TC Flashback, TC HOF. This setup worked great at home in my basement through my practice amp setup (Blackstar HT-5) with the TC pedals in the loop. Where I had problems was anytime I took it out of the house to jam/gig. I got a ton of buzz and 60 cycle him when playing at loud volumes with a hard rock level of gain. It varied based on the given electrical in a room but could be quite distracting when playing through my Marshall. I tried numerous ways to get rid of it but no matter what I couldn't. Eventually I just bought a Voodoo Lab Pedal Power 2+ and it's dead silent with my current setup so I don't plan on changing that. DC Bricks are fine too, but as keto mentioned they aren't isolated either so like the 1-spot if you play with a lot of volume and gain you're going to get noise if you're using a lot of pedals.

If all I ever did was hack around in my basement the 1-spot would be fine for me, I never had an issue with it and I still keep it in the bag as a backup. I would say if you're fine with your Boss setup I don't think upgrading to a 1-spot would really change anything other than having one less thing to plug in. I can't speak to having issues with it not powering pedals properly because I never had that issue, but that's just my experience. Hope that helps!


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## dradlin (Feb 27, 2010)

I've heard that when a switching power supply fails, in can blow all downstream devices from a power surge since the output is not isolated from the input. Don't know if it's true but I have heard stories of the Godlyke stuff failing with such an effect.


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## Moosehead (Jan 6, 2011)

I use a godlyke and never had a problem until I put a boss rc-3 on the board. Maybe its because its digital? I know mhammer has touched on this before. Something about boss digital and analogues not working well on the same power supply iirc. 

My board is layed out wah, tuner, dano tod v2, redwitch fuzzgod, v4 op amp muff, 70's ac powered ehx deluxe elec mistress, boss ce-2 (was pulled and rc-3 plopped in its place, problems ensued and went back to ce-2), and finally tc vintage delay/trex replica (same pedal, trex made them for tc) this also has its own power supply. 

I need to try the rc3 on an independant supply as I think this will solve the problem.


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## Greg Ellis (Oct 1, 2007)

If the PSAs are working for you, I'd stick with that and save up for a real PRO-class power supply.

With the sort of pedal board you're talking about, it's worth it.

I think your current system might ALREADY be superior to the One Spot and Godlyke.

I use a DC Brick for about 6 or 7 pedals, and it's been pretty decent. There are lots of other options, like the Voodoo.

A higher end unit might seem like a lot of money, but it will last for years, and feed a good number of pedals with good clean power. Worth considering at least.


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## mhammer (Nov 30, 2007)

RG Keen (the designer of the One-Spot) and I have been friends for over 20 years. He is an avid gatherer of customer feedback about the One-Spot, and Visual Sound makes a point of posting an updated list of what pedals are known to work fine with it. RG is also well aware of what can go wrong with a switching power supply and absolutely fanatical about circuit protection. If you check his geofex site, you'll find plenty of projects and notes regarding ways to protect pedals from various sorts of power-related catastrophes.

Having said that, daisy-chaining pedals, especially digital ones, can lead to problems, unless the pedal manufacturer has taken aggressive steps to avoid them. In particular, digital pedals can carry high-frequency spikes on their power lines. While a 5mhz clock that steps a DSP through its paces is not going to be audible, if another pedal is running a clock that is nominally 5mhz, but actually juuuusssttt a little faster or slower, say, by a measly 5-10khz, those power line spikes can interact to produce a sum and difference if they are sharing common power which is not sufficiently isolated between them. The sum will obviously be even more inaudible, but the difference may turn what was delightfully quiet pedals into beehives. I've experienced it, and so have many others. 

It is also the source of confused complaints from people who may have been running a bunch of daisy-chained analog effects, along with one digital pedal. Everything runs fine until they add a second digital pedal, and start experiencing all this noise. Naturally, unless better informed, they tend to blame the second digital pedal as being noisy and a piece of crap.

One of the reasons why we see the emergence of power bricks with multiple isolated outputs is not only for convenience purposes (so custom-length power cables can be run from each output to a given destination), but so that the electronic isolation of the various outputs will permit multiple digital pedals to be powered from the same source without inviting all the noisy gremlins.

Switched supplies like the Godlyke and OneSpot will continue to be terrific solutions for folks running all analog pedals and maybe one digital. Once you start running multiple digital pedals (the all-Strymon/TC pedalboard), power bricks become necessary.

Mark


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## High/Deaf (Aug 19, 2009)

dradlin said:


> I've heard that when a switching power supply fails, in can blow all downstream devices from a power surge since the output is not isolated from the input. Don't know if it's true but I have heard stories of the Godlyke stuff failing with such an effect.
> 
> 
> Sent from my iPhone using Tapatalk


All true! (Well, except for the Tapatalk thing - I can't vouche for that.....)

And if you are really 'lucky', a $30 Godlyke supply can wipe out an OCD, a Boss BF2, an Exotic SP, and a VH Phase 90. 

I got the supply in a kit, which I bought mostly for the daisy chain cables and adaptors. I only used it at home messing around, as my pedal boards already had power supplies installed. But one evening, it made a high-pitch whine and then the smoke came out. And not just from the power supply. 

Returned it to point of sale (it was only 2 months old) and all they would do is replace it!!!! Yikes. Kinda like having a defective hand grenade and being offered another one (for your other arm?) to compensate for the defective one. NO THANKS!

But I do now 'spread the love' about Godlyke whenever given a chance. Unless all your other pedals are expendable, I wouldn't touch one.

As an aside, the one thing I would (and probably will) consider is the new rechargeable battery packs. Last for hours, and absolutely zero hum/interference/etc. Also, limited current if things were to go sideways.


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## mhammer (Nov 30, 2007)

Myself and RG also recommend to folks to consider battery packs, whether NiMh, lithium ion, alkaline, rechargeable gel-cel or lead-acid, or anything else (e.g., power packs for power tools). A 6 or 8-pack of D cells will provide hours and hours of ripple-free DC to a pedalboard. One of my amps is a battery-operated 2-watter I built, that runs off 8 rechargeable C-cells.....hum free.

Of course, 12 volts' worth of C or D cells can also provide a LOT of current if things "go sideways".

Whether one uses a pure DC source, or something that converts household AC into an approximation of DC, there will always be the matter of when it is appropriate to daisy chain, and when some more sophisticated form of isolating power is desirable or necessary.


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## allthumbs56 (Jul 24, 2006)

Well ............... arggg! Off I went to practice last night with a much quieter board. I had one Boss PSA (200 ma) feeding the TU-2, FDII, SD-1, OCD, PSM-5 (used to switch in my "lead" pedals) which are BB Pre, SD-1, and DD-3 and lastly an H2O - these apparently add up to a required 180 ma. On a separate PSA I had a Digidelay and PS-5 (160 ma). Worked great at home.

Somewhere between testing and start of practice it developed a dead short - everything lit up but no signal whatsoever. Had to be when I was cleaning up the wiring (tape, Velcro straps, bundling). After messing with connections for 20 minutes with band mates restless I finally yanked the FDII and SD-1 with a power supply each and made do.

As I said, Arggg.

I can't afford to buy two Bricks or PedalPowers right now. The rechargeable packs I see are probably affordable (hundred bucks?) but do they support a dozen pedals for a 4 hour gig? I know nothing about them. Can I use one DC Brick and double-up on a few outputs - does that gain me anything in the noise department? Boss is making a switching supply that supplies 500 ma - is it the same deal as One-spot and Godlyke?

I'll say it again, Argg.


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## mhammer (Nov 30, 2007)

As a stopgap measure, you might consider running some of your pedals off internal battery, and others off external supply. naturally people balk at having to undo/unplug battery-powered pedals on a pedalboard, but there is a reasonably easy solution. Simply stick an unconnected 2.1mm plug into the power jack when you're done playing. It will disconnect the battery from the circuit, and you can leave everything wired up on the pedalboard the way you want it. Then, when you're ready to play again, just pull out the plugs and the batteries are reconnected.

I might also draw your attention to this place, situated in your own neck of the woods (Niagara Falls), who have some very sweet prices on parts and power supplies: http://www.dipmicro.com/store/index.php?act=viewCat&catId=518 They don't have a huge assortment of inventory, but I have dealt with them on multiple occasions, and their prices and service are terrific.


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## julienpier (Aug 7, 2009)

Get this : http://electricmojoguitars.com/index.php?dispatch=products.view&product_id=371

It solved all my problems, it is strongly built, inexpensive, you have 6 outputs that are isolated in 4 sections, a total of 1000ma, you can daisy-chain them to power more than 6 pedals . It is, in my opinion, much better than the DC Brick (which is essentially a daisy-chain hidden in a pretty box) and it costs the same price! You can't go wrong with this power supply.


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## allthumbs56 (Jul 24, 2006)

mhammer said:


> As a stopgap measure, you might consider running some of your pedals off internal battery, and others off external supply. naturally people balk at having to undo/unplug battery-powered pedals on a pedalboard, but there is a reasonably easy solution. Simply stick an unconnected 2.1mm plug into the power jack when you're done playing. It will disconnect the battery from the circuit, and you can leave everything wired up on the pedalboard the way you want it. Then, when you're ready to play again, just pull out the plugs and the batteries are reconnected.
> 
> I might also draw your attention to this place, situated in your own neck of the woods (Niagara Falls), who have some very sweet prices on parts and power supplies: http://www.dipmicro.com/store/index.php?act=viewCat&catId=518 They don't have a huge assortment of inventory, but I have dealt with them on multiple occasions, and their prices and service are terrific.


Well, first I'll find that short. Then on to the "noise". It's definitely new - nothing like the accumulated buzz from stacked od's. More of a wind tunnel thing. If I understand you correctly, a lot of the noise may be a result of 2 or more digital pedals fighting with each other. I know that I have used the H2O and the DD5 for years together with a single chain, but the Digidelay and the PS5 are recent additions. I've got space under my pedaltrain for probably 3 warts on a powerbar - perhaps I should try giving the Digi and the PS5 their own supplies - maybe that'd help.

- - - Updated - - -


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## allthumbs56 (Jul 24, 2006)

julienpier said:


> Get this : http://electricmojoguitars.com/index.php?dispatch=products.view&product_id=371
> 
> It solved all my problems, it is strongly built, inexpensive, you have 6 outputs that are isolated in 4 sections, a total of 1000ma, you can daisy-chain them to power more than 6 pedals . It is, in my opinion, much better than the DC Brick (which is essentially a daisy-chain hidden in a pretty box) and it costs the same price! You can't go wrong with this power supply.


That seems very interesting. I also see that they have a Joyo power supply with_* 10 isolated outputs f*_or 60 bucks. It looks to be wall-wart driven though. Anyone know anything about these?


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## mhammer (Nov 30, 2007)

Nothing wrong with that configuration. Just like effects or rack units that can stick the power transformer inside the chassis, or use a wallwart and plug that into the chassis, the Joyo unit resorts to the transformer in one package, and puts the regulation into the chassis that goes on the pedalboard. The regulators in that box all need at least 2Vdc more on their input than they provide on their output, so an 18V wallwart takes care of that part.

I have a much cruder version of that, that I've built several of for myself. In one instance, the unit is essentially a "multiple", whose input is a regulated 9VDC distributed to 4 additional 2.1mm jacks, and is given a tad more smoothing via a big capacitor, and a "power on" LED is provided. A person can cascade several of these, such that a one-in-four-out box sits in one corner of the pedalboard, and a cable links a second unit situated in another corner of the pedalboard. the units are entirely passive.

A second version provides active regulation and is more or less a stripped down version of the Joyo thing. Input is 12vdc from a wallwart, and that goes to a half-dozen individual 100ma 9V regulator outputs. The 12vdc wallwart doesn't have to be especially well-regulated, since its output will be down-regulated all over again. If the wallwart becomes dysfunctional in some manner, any old 12-18vdc wallwart of sufficient current will do as its replacement. In that sense, the Joyo approach can be economical and flexible. You could probably even use a 15vdc wallwart, though you'd lose the 18v output in that case.


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## allthumbs56 (Jul 24, 2006)

mhammer said:


> Nothing wrong with that configuration. Just like effects or rack units that can stick the power transformer inside the chassis, or use a wallwart and plug that into the chassis, the Joyo unit resorts to the transformer in one package, and puts the regulation into the chassis that goes on the pedalboard. The regulators in that box all need at least 2Vdc more on their input than they provide on their output, so an 18V wallwart takes care of that part.
> 
> I have a much cruder version of that, that I've built several of for myself. In one instance, the unit is essentially a "multiple", whose input is a regulated 9VDC distributed to 4 additional 2.1mm jacks, and is given a tad more smoothing via a big capacitor, and a "power on" LED is provided. A person can cascade several of these, such that a one-in-four-out box sits in one corner of the pedalboard, and a cable links a second unit situated in another corner of the pedalboard. the units are entirely passive.
> 
> A second version provides active regulation and is more or less a stripped down version of the Joyo thing. Input is 12vdc from a wallwart, and that goes to a half-dozen individual 100ma 9V regulator outputs. The 12vdc wallwart doesn't have to be especially well-regulated, since its output will be down-regulated all over again. If the wallwart becomes dysfunctional in some manner, any old 12-18vdc wallwart of sufficient current will do as its replacement. In that sense, the Joyo approach can be economical and flexible. You could probably even use a 15vdc wallwart, though you'd lose the 18v output in that case.


Well, I just ordered the Joyo. Never dealt with Mojo before but I've already got an email from Charles thanking me and telling me that it'll be shipped today. Unfortunately I have a gig Saturday so I better get down to my bench and patch something together.

I will report to you fine gents once I receive and try it out. I think for the price and if it's as advertised it'll be pretty hard to beat. I will have to chain 3 pedals together on one tap but that should work out I think (heck for the money I'll buy another one). Added bonus is the 18V tap so I can lose the batteries out of my old 535Q.

Thanks for all the input guys.


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## surlybastard (Feb 20, 2011)

Let us know how it goes with the Joyo, especially at higher volumes. This won't make any difference to you now as you've already ordered the Joyo but what I will say is I was trying to find ways to cut corners and use my 1-spot for a year and guys on forums were telling me "I know the Voodoo costs a lot but once you get it you'll never have to worry about this problem again", when I finally got the Voodoo all my issues were gone and I wondered why I wasted so much time using other power supplies. Point being, yes they're expensive but I really wish I'd just listened to people and spent the money earlier so I didn't have to worry about it. I read up on the Joyo and I'm not sure it's isolated like a Voodoo (depends on your definition), based on my reading it strikes me as being closer to a DC Brick than a Voodoo, but like I said a switching power supply may work just fine for your application. Best of luck!


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## mhammer (Nov 30, 2007)

The relative suitability of the power supply will depend on the pedals one is using it with. A 1-Spot , hell, even a $4.99 wallwart from a Dollar Store, can be just fine for a wide variety of pedals and uses, without any problems supplying enough current, or contending with power-line gremlins. Change/add some digital stuff, and it may be insufficient, whether in current capacity, or noise immunity.

The more expensive and exotic supplies have arisen over time, not because their predecessors were utter crap, but because the requirements of supplies kept getting upped by the variety and number of pedalboard contents musicians started using.


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## allthumbs56 (Jul 24, 2006)

surlybastard said:


> Let us know how it goes with the Joyo, especially at higher volumes. This won't make any difference to you now as you've already ordered the Joyo but what I will say is I was trying to find ways to cut corners and use my 1-spot for a year and guys on forums were telling me "I know the Voodoo costs a lot but once you get it you'll never have to worry about this problem again", when I finally got the Voodoo all my issues were gone and I wondered why I wasted so much time using other power supplies. Point being, yes they're expensive but I really wish I'd just listened to people and spent the money earlier so I didn't have to worry about it. I read up on the Joyo and I'm not sure it's isolated like a Voodoo (depends on your definition), based on my reading it strikes me as being closer to a DC Brick than a Voodoo, but like I said a switching power supply may work just fine for your application. Best of luck!


Yeah, they claim that it is isolated but I saw a video review in which the reviewer said it wasn't. Truth in advertising. Maybe Joyo would claim that it's the way Chinese gets translated to English. Like each output is "isolated by half an inch from the next one" or something like that. Regardless, the reviewer (and others) say that it is considerably quieter than the DC, Godlyke and One-spots.

FWIW, after considerable dicking around I have my board at an acceptable noise level using 2 traditional PSAs - feeding the PS-5 and Digidelay separately from the other pedals - these do seem to be the 2 that don't play well in the sandbox. This will do for the next gig. I found a bad signal cable and then upon bundling it up discovered a bad power lead on one of the PSAs too.

Will report on the Joyo soon. In the very least it's cheaper than the Brick.


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## mhammer (Nov 30, 2007)

If the outputs have a "100ma rating", then they are using a 3-pin voltage regulator. That provides a fair amount of isolation. But, much like "regulation" itself, there are degrees of it. So, one supply can be more regulated than another, and another supply can have outputs that are more isolated from each other than a different supply's outputs are.

This review - http://www.amazon.com/JOYOS-IMPROVED-JP-02-SUPPLY-OPTIONS/product-reviews/B0097WDJZA - details the reviewer's concerns about what he feels is marginal isolation. The 9v outputs are all fed from a common regulator, and the 12v output from another. In that respect, the Joyo's 9v outputs are a bit like a 1-spot daisy-chain, but with separate jacks. In that respect, perfectly acceptable for analog pedals, and one digital, but a possible risk with more than one digital pedal connected to the 9v outputs.

Although let me qualify that.

Just as power-supply makers have been moving steadily towards accommodating digital pedals by isolating the outputs from each other more, digital pedal makers have been moving in the direction of providing more protection against line noise arising from shared power supplies, simply because they have no interest in their products being rumoured to be noisy crap due to underinformed consumers. So they are incorporating aspects into the onboard power regulation circuitry (and digital pedals will generally take that 9vdc and turn it down to 5vdc on board) that prevents clock noise from finding its way out over thepower lines. In a sense, pedal makers and power supply makers are meeting each other halfway more and more.


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## allthumbs56 (Jul 24, 2006)

Thanks for the research Mark. Things just shouldn't be this complicated. I do hope that the Joyo will be an improvement regardless of whether it is isolated or not (or partly to some strange degree) - what I've read now suggests that "isolation" requires a virtually a separate transformer for each output.

Will I like my FDII at 18v? How about my OCD at 12?


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## dradlin (Feb 27, 2010)

mhammer said:


> Just as power-supply makers have been moving steadily towards accommodating digital pedals by isolating the outputs from each other more, digital pedal makers have been moving in the direction of providing more protection against line noise arising from shared power supplies, simply because they have no interest in their products being rumoured to be noisy crap due to underinformed consumers. So they are incorporating aspects into the onboard power regulation circuitry...


One could argue that a manufacturer's pedals are "crap" if they are susceptible to noise when manufactures chose not to include protection against line noise. That is not the fault of an uninformed consumer, but rather the laziness, ignorance, or arrogance of the manufacturer. 


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## mhammer (Nov 30, 2007)

I wouldn't be that harsh. How is it the manufacturer's responsibility to be able to meet the most stringent requirements the industry might pose them with? I can power a bunch of traditional analog pedals with a $3 AC adapter and a daisy-chain cable, and it is perfectly fine. If a manufacturer has met those needs, but doesn't meet more demanding ones, where's the sin?

But where I think we will both agree is that it DOES become the manufacturer's ethical and professional obligation to fully, and clearly/comprehensibly, inform the consumer what their product will NOT do. How much of that failing is a result of: a) the "language thing" (i.e., Asian manufacturers), b) the industry hype culture (including reviewers' failure to raise such matters or explain them well), c) the perception that consumers just wouldn't get it anyway, or d) deliberate abdication of responsibility by the manufacturer, is something I can't assess.

Where I am a little annoyed at JOYO, with respect to this supply is that their product *looks* very much like its more complex competitors. I know I was certainly persuaded, until I saw the comments from the reviewer I linked to earlier. I know what ought to be inside one of those things, but the vast majority of musicians would not.


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## mhammer (Nov 30, 2007)

allthumbs56 said:


> Thanks for the research Mark. Things just shouldn't be this complicated. I do hope that the Joyo will be an improvement regardless of whether it is isolated or not (or partly to some strange degree) - what I've read now suggests that "isolation" requires a virtually a separate transformer for each output.
> 
> Will I like my FDII at 18v? How about my OCD at 12?


Like I indicated, there are degrees of isolation, just as there are degrees of regulation. Having a separate transformer tap is one way to isolate effectively, but there are others. Personally, I'm content to feed a cluster of 3-pin regulators from a higher DC voltage source through a power diode. So, feed a 1A 12VDC source to a common point, send it out through paralleled 1N4001 diodes (reducing 12VDC to 11.5VDC) to an octet of 100ma 78L09 regulators, each with their own 470uf smoothing cap, and you should see very little interaction between them.

On the other hand, I don't run a recording studio, don't run any of my gear very loud, and am likely to experience more noise from the damn fluorescent fixtures in the house than from any pedal crosstalk through the power lines, so what works just peachy keen for me may be insufficient for a studio or PA person trying to eliminate every conceivable ground loop.

As for the supply voltage thing, I'm less of a believer than many are. Remember that, while increasing the supply voltage does, in theory, raise the headroom, the modus operandi of an overdrive is that it _deliberately restricts_ headroom, although they can each do so I different ways. My hunch is that the change may be more audible in the OCD than in the FDII. The OCD clips via diode action going to ground, where the FDII (as a TS9 derivative, if my info is correct) clips via diode action in the feedback loop of an op-amp. In the former case, there ought to be an audible difference in the signal being fed to those clipping elements by a chip that has a little more breathing room (due to higher supply voltage), whereas in the later case, the ceiling on the chip is fixed, irrespective of the supply voltage. But, as with many things, this is an empirical question, to be confirmed or disconfirmed by use. Both of those pedals have twists and turns that may well benefit from more supply voltage. 

Sadly, in the majority of cases where people try a higher supply voltage, they do not do so in a manner that allows for instant A/B comparison. What's really needed is a nice blind A/B comparison where the manipulator has a switch to select between two different supply voltages (say, 9 and 15v), and has the player plug in on the other side of a visual barrier. The manipulator asks "Which do you prefer, A or B?", and keeps a record of what A and B are for each of, say 25 trials. The controls are left the same all the time, and the player is allowed to wank away for 5-10sec on A and then B, before offering an opinion. Sometimes A is 9V, sometimes A is 15V. Sometimes, A and B are different, but sometimes they are the same. If 15V is always preferred, whether A or B, and no preference is given when both A and B are 15V, then you know you have something real. If the 2nd one (B) is usually preferred, regardless of whether A and B are identical, or whether B is 9V or 15V, then you know you don't have something real.


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## surlybastard (Feb 20, 2011)

FYI I run my OCD is 18v and there's quite a significant difference, although as you said I didn't do a blind test so maybe I'm listening with my eyes. I always liked the pedal in 9v, but in 18v it really opened it up, made it clearly and more pronounced. Basically, to my ear it emphasized a lot of what I really liked about the pedal. The problem at the time was that I only had one 18v adapter and two pedals I needed to run (the other being an EVH Flanger which has 18v requirement), eventually I got a wall wart 18v for the EVH and then used a voltage doubling cable for the OCD, I don't think I could go back to 9v now.


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## mhammer (Nov 30, 2007)

Here is an attempt at an explanation of what is happening, using the schematic posted here: http://revolutiondeux.blogspot.ca/2008/07/fullclone-vlod-fulltone-ocd-by.html

The OCD first amplifies the signal in the op-amp shown by the first TL082 triangle. With the given component values, it can amplify up to approximately 464x. Upon exiting the op-amp, that signal is clipped by the pair of 2N7000 transistors (used in diode mode) and the additional 1N34A (which arranges for the clipping to be slightly asymmetrical).

Let us say that the input signal you feed the pedal is +/-100mv. It likely will only be that high for the first 50msec of a plucked note, and then start to decline in amplitude. The datasheet for the op-amp chip says that it will only be able to "swing" +/-13.5V with a +/-15V supply. This implies that, with a 9V supply, it is unlikely to be able to "swing" to within 1.5V of either extreme (+9V or 0V). That gives us our limit of roughly 6V, or +/-3V.

Okay, now divide 100mv into 3V (3000/100), and we see that applying a gain of more than 30x to the input signal and we have essentially run out of headroom on the chip. Given that guitar notes quickly decline in amplitude after that first little attack transient, we'll say that, for a humbucker "listening" to a wound string plucked hard with some finger vibrato keeping it alive for a while, we should probably have 30mv for a couple of seconds. So, a conservative estimate would suggest we could set our gain control for around 100x, and with a 9v supply, there's a reasonably good chance that most of the clipping we are hearing is coming from the diode and pair of 2N7000s, and NOT from the op-amp itself.

Were we to switch to an 18v supply, that would now allow the signal to swing between 1.5 and 16.5V in the op-amp, or 15000mv. Divide 30 into 15000 and you can see that with a higher supply voltage, there are hypothetically many more occasions when the Drive control can be dimed, and the clipping will come pretty much exclusively from the 2N7000s and diode, and not from the op-amp.

The change in supply voltage doesn't necessarily change the _behaviour_ of the components, so much as it changes the pedal from being a sort of "double clipper" (like a Big Muff is, where the signal is clipped, and then clipped again) to a single clipper.

The manner in which the higher supply voltage allows the op-amp to not run out of headroom in many instances is responsible for the sense that it can "breathe" more with 18V. The FDII has a different internal structure/architecture, where the full headroom of the chip is never used, so the change in supply voltage is not expected to make a difference. That doesn't make it a lesser pedal, just one which is not amenable to an external manipulation like monkeying with the supply voltage.


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## allthumbs56 (Jul 24, 2006)

Well the Joyo arrived yesterday. Super-quick service from Electric Mojo. Looked great and well-built. Hooked it up immediately to 10 pedals on my board (12v to FDII and 18v to OCD - beautiful!). Fired her up. Sadly, the unit is absolutely useless to me. Noisy beyond belief. I tried several different configurations and kept diconnecting pedals until I was down to only two. Even powering just two analog pedals (an FDII and an OD-3) the Joyo was easily twice as noisy as the Godlyke Powerall powering all eleven. I'm hoping that the one I got is defective but as it is it's useless. So for the gig tonight I'm back to using two Boss PSAs - whisper quiet compared to my experience so far with "digital switching units".

I have yet to contact Charles at Mojo but I expect that he'll be surprised and I'm sure we'll work something out. As I said, perhaps this unit is defective.


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## mhammer (Nov 30, 2007)

Just out of curiosity, what sort of noise? Hum?


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## allthumbs56 (Jul 24, 2006)

mhammer said:


> Just out of curiosity, what sort of noise? Hum?


It's kind of a "roaring hum". Much like I was getting from the Godlyke Powerall but several times worse. I was able to use the Godlyke in a band situation but really needed to switch off pedals between songs or the crowd could hear it. I would not attempt to use the Joyo in any situation.

I have been in contact with Charles at EM and he's being very gracious and helpful. He says he's had enough trouble with the Joyo that he's pulling it off the shelf. He's suggesting the Cioks BigJohn or the Decibel 11 Hotstone SM as possibilities. Two things I'm not sure about on the Cioks are that the outputs seem to be isolated in groups and that it uses funky connectors at the one end (RCA jacks?) that might cause some grief if I wish to daisy chain a few pedals. The Decibel 11 looks good but I don't know that it'll mount under my PT2. My other choice is a VL ISO5 from the local L&M for $130 which I believe will fit the board, take an 18v pedal and allow some careful daisy chaining.


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## allthumbs56 (Jul 24, 2006)

Well, Charles at EM is offering me the Decibel 11 Hotstone SM for a good price and it will fit under my board using the brackets designed for the Voodoo Labs box. I think I'll go for it.

I'll report back on how it turns out.


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## surlybastard (Feb 20, 2011)

Two things: 1. I should've prefaced that the noise I was having with switching supplies was with all the pedals *off*. With OD's on, no matter what power supply you buy you can't get rid of that without a noise gate of some kind. I only mention this because you talked about having to turn the pedals off between songs.

2. Decibel 11 is the same as a Voodoo so that should solve any problems you're having. Good luck!


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## mhammer (Nov 30, 2007)

Unless a pedal is cut off from power, it is never "off", merely bypassed. And if the power is connected, then all the power-line spikes are all still there and travelling along unisolated power lines.


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## surlybastard (Feb 20, 2011)

mhammer said:


> Unless a pedal is cut off from power, it is never "off", merely bypassed.


Yes, thank you for correcting me Captain Obvious. I think he understands what I meant.


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## epis (Feb 25, 2012)

Hi everybody, I'm watching this tread with great interest. Mark's posts are like effect pedals technology poetry :applouse:.
I have a question for Chris : What setup are you using for your pedal board ? All in front of your amp, or some pedals in front and some in effects loop ?
I assume you're using time based effects in loop. In that case you have a problem with ground loops causing the hum.
You need ground isolated power supplies. You can try for start using two daisy chains, one for pedals connected to the input of the amp and second one for pedals in effect loop. But final solution should be real ground isolated PS like Decibel 11 or Voodoo. That would solve a problem with multiple digital effects in chain as well as Mark mentioned before.
About Joyo PS, judging by the Google images, there is two groups of insulated outputs. So eventually you could use one for in front of the amp effects and second for effects loop.
If you have a multimeter it would be easy to find witch output belongs to witch group. Just check for continuity between the pins in output jacks.
Cheers, Damir


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## allthumbs56 (Jul 24, 2006)

epis said:


> Hi everybody, I'm watching this tread with great interest. Mark's posts are like effect pedals technology poetry :applouse:.
> I have a question for Chris : What setup are you using for your pedal board ? All in front of your amp, or some pedals in front and some in effects loop ?
> I assume you're using time based effects in loop. In that case you have a problem with ground loops causing the hum.
> You need ground isolated power supplies. You can try for start using two daisy chains, one for pedals connected to the input of the amp and second one for pedals in effect loop. But final solution should be real ground isolated PS like Decibel 11 or Voodoo. That would solve a problem with multiple digital effects in chain as well as Mark mentioned before.
> ...


I'm using a Deluxe Reverb Reissue and a Princeton Reverb, all effects in front. On the board currently are a TU-2, BB Pre, FDII and Rat. after the Rat is a Boss PSM5 that can bring in a "lead loop" consisting of an OD3, OCD and a DD3. This returns to the PSM5 which is followed by a PS-5, a Digidelay, and an H2O which splits the outputs to the 2 amps. This setup used to operate out of a home-made board that used 3 traditional wall warts - no noise issues. I then got a Pedaltrain II and thought it would be an elegant solution to use the Godlyke Powerall for the entire board - including an 18v powerpump to add in my 535Q wah from time to time For a while I had used the Godlyke on a small board (Tuner, FDII, OD3, DD3, and H20) without issue. On the big board I started getting a lot of noise - it appears that the PS5 and Digidelay are the big offenders as last night I rigged up two Boss PSAs - one to the two suspects and the other to the other nine pedals. Noise level was acceptable for the gig. The Joyo was a disappointment - it was very noisy with just two od's in use. It's on its way back and a Hotstone SM will be arriving. Some pedals will have to be paired up but all digital pedals will have their own isolated supplies. It has to be an improvement.

I hope that explains it. I should have the Decibel 11 mid-week and will report on it soon after.


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## allthumbs56 (Jul 24, 2006)

OK then, the Decibel 11 Hot Stone SM had arrived and been installed. Using two strips of foam weatherstripping to provide some spacing, the box installed under my Pedaltrain 2 using the brackets they provide for VoodooLab boxes. AC-in goes through the hole same as for the Voodlabs. There are a total of 8 outputs, 6 of which are isolated (2 pairs are high-current - 300 ma each and have both 9v and 12v taps). As my board sits now I have used 7: 1 each for the Digidelay, H20, DD-3, PS-5 (total 4), 1 for the Rat (connector provided), and 1 - 12v tap for the OCD. I am using the 2nd 300 ma output with daisy-chain for the TU-2, FD II, BB Pre, OD-3, and the PSM-5. She's pretty quiet, and heavy for such a little box. I will redo the wiring when I get some cables made up and also intend on trying a Godlyke Powerpump to see if I can get 18v for my wah - I figure that if it worked with the Powerall why wouldn't it work with any 9v source (Mr Hammer?).

Charles at Electric Mojo has been excellent to deal with and I would highly recommend him to anyone, ................. really, how could I say anything negative about a guy who sells Fano guitars!


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