# Annoying digital whine in my rig



## hollowbody (Jan 15, 2008)

I've noticed this a couple times now. A couple weeks ago at rehearsal it was so bad that I had to put the amp on standby between songs. Last night it wasn't that bad, but the bar owner definitely commented about the buzzing. I figure it's time to do something about it.

It's clearly related to whatever else in on the circuit, since I don't hear it at all at home, but in the rehearsal space where there's a full band's worth of gear on the same circuit, it's noisy as heck. I have a couple power conditioners I could use (the cheapy ART PB 4x4), but I was wondering if using something like a ISP Decimator would help in this regard? I had one a while back that I used to calm down my P90s, but I sold it after I sold the P90 guitar.

I'm also planning on checking all my power. I've read that conflicting digital clocks on my pedals can create noise. I'm certainly running a ton of digital pedals. Here's my board:









The signal path is:
Guitar -> A/B -> B9

B9 wet out -> Mini Vent -> Volume -> DI -> FoH
B9 dry out -> Wah -> tuner -> Switch Dr.

Switch Dr. loop 1 - Comp
Switch Dr. loop 1 - Octasynth
Switch Dr. loop 1 - Classic Distortion Pro
Switch Dr. loop 1 - Klon

Switch Dr out -> H9 -> amp

Now, the signal to my guitar amp only has the H9 and Source Audio pedals in it, and the Source Audio is out of the loop sometimes when I'm playing clean, but the whine still persists (albeit less intense when the Source Audio is out, or on a lower gain setting). BUT there are other digital pedals on the board (B9, Mini Vent, Line 6 G30 under the board, Switch Dr.) and I'm wondering if one of them is starved for power.

I'm currently using a PP2+ and a PP2+ Digital to power everything, so it's quality stuff, but perhaps I still need more current? Everything should be isolated from one another, but there's still some noise. I suspect the issue might be whichever of the digital pedals I'm feeding power to from the PP2. I might have to substitute a couple of the cable with my current doubling cables and then use a daisy chain for the regular 9V stuff. 

Lots of things I can try out, but I figured I'd scratch your heads for options, too, in case there was something that I had missed.


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## LydianGuitars (Apr 18, 2013)

The first thing you need to do is isolate which pedal is whining. 
The most common issue is a bad power connection. Find the pedal, clean its power jack and reflow the solder joints on it (the jack). That's a first step.


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## hollowbody (Jan 15, 2008)

LydianGuitars said:


> The first thing you need to do is isolate which pedal is whining.
> The most common issue is a bad power connection. Find the pedal, clean its power jack and reflow the solder joints on it (the jack). That's a first step.


Hopefully switching around 9v cables will help. The less I need to solder, the better! 

The issue is that I don't really hear it at home, so it'll be hard to even troubleshoot. I'll have to turn up the amp quite a bit and muck about for a while. Hope the neighbours don't mind!


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## Alex (Feb 11, 2006)

Have you tried just plugging into the amp at the said bar to confirm the squeal is in fact related to your board? May be a case of "dirty power" . I've only owned one power conditioner and it was a cheap one so I can't help. nice board btw.


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## mhammer (Nov 30, 2007)

It is a well-recognized issue that when two or more digital pedals are sharing the same power source, the sum and difference of the various clock signals riding on their power lines can produce audible whining.

F'rinstance, assuming there are two clocks with a .01% tolerance, you won't hear 2.001mhz, and you won't hear 1.999mhz, and you certainly won't hear 4mhz, but if they clash and produce a difference signal of 1khz, you *will* hear that.

The frustrating thing is that each pedal, on its own, will be blissfully quiet. The whine will occur when both are used and sharing a common power source. If each is powered by a separate supply that is isolated from any other supply, there won't be an issue.

Pedal makers have taken note of this issue, and more are including the sorts of power filtering that prevents clock signals from leaving the pedal on the power line and getting into an argument with those of another pedal. But it is not universal, unfortunately.

BTW, the whining issue is technically referred to as "heterodyning", and is a close relative of ring modulation.


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## Mooh (Mar 7, 2007)

Very informative again mhammer. Wish I'd known this last time I ditched my pedal board for multi-fx, not that I'm unhappy with the Boss ME-80 (I love the thing really) but I sometimes miss the individuality of the old board. Messing about with pedals was a singular joy.

Peace, Mooh.


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## hollowbody (Jan 15, 2008)

Alex Dann said:


> Have you tried just plugging into the amp at the said bar to confirm the squeal is in fact related to your board? May be a case of "dirty power" . I've only owned one power conditioner and it was a cheap one so I can't help. nice board btw.


Thanks! It's been an ongoing project and I think I'm finally getting near to where I want it to be. I need a LOT of flexibility for my cover band since we do 7 decades' worth of music 

I definitely know dirty power is part of the problem, as the issue is more pronounced in certain places. I told the owner yesterday that since there was only one set of outlets on-stage and we had to plug everything (guitar amp, pedalboard, bass amp, bass pedalboard, keyboard, vocal effects, lighting) into it, that was the cause of the problem. But I definitely think there are things I can do to address this and make it a bit less quiet on my end.



mhammer said:


> It is a well-recognized issue that when two or more digital pedals are sharing the same power source, the sum and difference of the various clock signals riding on their power lines can produce audible whining.
> 
> F'rinstance, assuming there are two clocks with a .01% tolerance, you won't hear 2.001mhz, and you won't hear 1.999mhz, and you certainly won't hear 4mhz, but if they clash and produce a difference signal of 1khz, you *will* hear that.
> 
> ...


I'll have to peek under the hood to see where the H9 and Soundblox pedals are plugged-in. I suspect they're both in the PP Digital. Maybe I can plug the Soundblox into the PP2 with my current doubler to further isolate them (even though the individual taps on the PP units are supposed to be isolated).

I also read that underpowering digital effects can result in noise. So far, everything powers-up and works properly, so it seems like everything is receiving enough current, although I know in some cases the current flowing to those pedals is definitely below what is recommended in their manual. Perhaps a bit more juice will cause them to work more happily. I'll have to dig out those current doubling cables. I'm glad I didn't sell them!


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## mhammer (Nov 30, 2007)

When players might have one digital pedal, and a bunch of analog pedals, sharing the same power brick, it wasn't an issue, so nobody did much about it. But once more pedal-makers started migrating to the digital domain, even for fuzzes, filters, phasers, etc., or using hybrid approaches, the way Empress and Chasebliss do (analog audio path with digital control), it started to become a more prevalent problem and manufacturers started paying attention to it. It could be addressed within the pedal, but could also be addressed by the degree of regulation and filtering in each output of the power brick.

Incidentally, most small wallwarts that deliver lots of current for a tiny package use switching regulators that _also_ have clocks. If they are well-regulated, no problem. But if they are not especially well-regulated, then it can be like having two digital pedals clashing, even if you are only powering one digital pedal with the wallwart. Unfortunately, the culprit is HF clocks you can't hear on their own, and it's not like pedals and wallwarts tell you what clock-frequencies are in use in the device so you could anticipate whether there would be any problematic hetereodyning or not.


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## mister.zed (Jun 8, 2011)

I think this might be the issue I'm hearing too. Because I couldn't isolate it to a single pedal it was driving me insane. But what you describe is consistent with that. Arghh..... more money for something that doesn't make sound (pun intended).


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## High/Deaf (Aug 19, 2009)

The fact that this is not inherent in the board but seems to be a problem with that one venue makes me think something about the power at that site is interfering with a minor clocking problem on your board and making it worse. Another troubleshooting step may be to plug your board (or whole rig) into a UPS, isolating yourself completely from the venue's AC (a true UPS should have a DC/battery supply and an inverter. You don't really care about the battery capacity as you aren't expecting an AC fail, you only need the inverter for its isolation). 

If the problem goes away, you know it's a combination of things. The solution may be to use the UPS for those places that cause the problem. A UPS with enough capacity for a board should be less than $100. For your whole rig, probably still less than $150.


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## mhammer (Nov 30, 2007)

mister.zed said:


> I think this might be the issue I'm hearing too. Because I couldn't isolate it to a single pedal it was driving me insane. But what you describe is consistent with that. Arghh..... more money for something that doesn't make sound (pun intended).


In principle, it should be possible to make a power cable with a bi-directional in-line filter that blocks HF clock pulses riding on the power. SOMEBODY must make them. They just don't have broad enough marketing that we know about them. Maybe somebody will come back from Winter NAMM with some examples.


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## mhammer (Nov 30, 2007)

mhammer said:


> In principle, it should be possible to make a power cable with a bi-directional in-line filter that blocks HF clock pulses riding on the power. SOMEBODY must make them. They just don't have broad enough marketing that we know about them. Maybe somebody will come back from Winter NAMM with some examples.


Would a UPS fix it? I don't know. Perhaps not, since the smoothness of the power is separate from whatever HF clocks are being generate in the pedals themselves. That is not to dismiss the idea, since house power and switching power supplies _can_ be an issue, even for analog pedals. But it is no panacea since the power source is not the ONLY origin of such whining problems.


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## ed2000 (Feb 16, 2007)

Very basic check point: What is the wall outlet voltage, as read by a DVM? Is the polarity(using a Polarity Checker) correct at the source and the cable outlets?


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## hollowbody (Jan 15, 2008)

Lots of good options here. I'm gonna start with powering from wall warts and work my way back to the Voodoo Lab units in various configurations from there. I'll let you know what happens.


Sent from my iPhone using Tapatalk


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## High/Deaf (Aug 19, 2009)

mhammer said:


> Would a UPS fix it? I don't know. Perhaps not, since the smoothness of the power is separate from whatever HF clocks are being generate in the pedals themselves. That is not to dismiss the idea, since house power and switching power supplies _can_ be an issue, even for analog pedals. But it is no panacea since the power source is not the ONLY origin of such whining problems.


If AC at that location has a lot of noise from reactive loads (industrial motors, etc), yeah, a UPS would get rid of that external noise factor. Some AC in industrial areas is pretty noisy. A good power supply should filter that out, but if this is only happening at one location, that's where I'd start.


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## mhammer (Nov 30, 2007)

Back in the day, those of us with a few grey hairs to our credit, would experience interference with our music listening when mom used the vacuum cleaner or sewing machine, or dad used a power drill, or the fridge compressor came on. All these various motors would put spikes on the household power lines, and that would show up as annoyingly loud buzzing in the stereo, or perhaps snow on the TV screen in the middle of the Grey Cup or Stanley Cup, because the power lines were not well-filtered enough, and the appliances themselves did not do anything to prevent spikes from being created and "shared" with every other device sharing the same AC line.

In the case of digital pedals, though, there can be so many HF clocks that the heterodyning products often yield more of an intense white background noise than a clearly pitched buzz. I might add that some of the best analog cymbal synths I've heard or built use that exact same strategy - a handful of high-frequency clocks (though in the kilohertz rather than megahertz range) - ring-modulated with each other to create a complex unpitched set of sums and differences. as a noise source.


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## hollowbody (Jan 15, 2008)

This weekend turned out to be a no-free-time kinda thing. I've set aside some time on Tuesday night to work on this.

I read this today on one of the Eventide forums, regarding powering the H9 via a Voodoo Lab PP Digital:
*"You should power the H9 with 12V DC and use the green Flex cable. 4.5W corresponds to 375mA @ 12V DC. This means you should use the 12V outlet of a 400ma section and leave the associated 9V outlet not used (one to the left from the one used for the H9)."
*
Someone else posted on the Voodoo Labs forum this response they got from Eventide:
*"MF, TF, PF, Space and the H9 can operate from a 5W power source that supplies regulated 9 to 12VDC max.
The minimum required power ranges from a maximum of 4.5W at power up (all LEDs lit) to about 3.6W in normal operation depending on how many LEDs are lit.

For a regulated 12VDC, the current requirement is 380mA at power up and 300mA in normal operation. Do not use unregulated 12V.

For a regulated 9VDC, the current requirement is 500mA at power up and 400mA in normal operation."*

So far, I've been powering the H9 with a 9V supply. It's possible the noise is being created due to an underpowered pedal. I'm going to add feeding the H9 12V from my PP Digital as something to try. 

Regardless, I'm sure there IS a solution. The Voodoo Lab stuff is super reliable and built well. I've never had a problem with their stuff that wasn't in some way a result of me plugging things in wrong or accidentally hitting DIP switches. I'll get it sorted!


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## mhammer (Nov 30, 2007)

I doubt that the noise you are experiencing is a result of any "underpowering". The numbers given really have more to do with the way in which the on-board regulation works. As a digital pedal it doesn't need 9 or 12 volts. It needs 5 volts, and maybe even only 3.3V, but it gets that 5 or 3.3 from the external 9/12 supply and drops it down to the requisite 5 or 3.3.

Just to be clear, though, sometimes supply voltage does matter. I have a couple of Boss BF-1 Flangers. The chassis says to use 9VDC, but the service manual says to use 12VDC. Both work fine, but the sweep is much wider when using 12V. Of course that's an analog circuit. Your H9 is maybe 1% analog and that 1% is unaffected by 9 vs 12V.

That said, maybe in some cockamamie way, a clock inside the H9 has a slight variance as a result of supply voltage. Who knows. It's a big ol' wacky world.


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## LydianGuitars (Apr 18, 2013)

hollowbody said:


> This weekend turned out to be a no-free-time kinda thing. I've set aside some time on Tuesday night to work on this.
> 
> I read this today on one of the Eventide forums, regarding powering the H9 via a Voodoo Lab PP Digital:
> *"You should power the H9 with 12V DC and use the green Flex cable. 4.5W corresponds to 375mA @ 12V DC. This means you should use the 12V outlet of a 400ma section and leave the associated 9V outlet not used (one to the left from the one used for the H9)."
> ...



That's kinda what I was trying to convey in my original message. Clean power connections and solid solder joints are important in the digital world. I've seen noise coming out of digital assemblies (audio devices or not) and power is the 1st thing I look at. Some times, you can hear the oscillation from the physical devices themselves with under power conditions. 

I just fixed an Alesis mixer that was ringing with nothing plugged in or out of it except the power supply. The fix was to clean and reflow the DSP board supply connectors.

That being said, if the supply isn't powerful enough, that needs to be resolved 1st.


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## hollowbody (Jan 15, 2008)

Ok, I finally got around to clearing out my schedule and sitting down to do this last night.

So, initially, I had my power like so:

PP2
1 - wah
2 - tuner
3 - SP comp
4 - Klon
5 - Switch Dr.
6 - B9
7 - A/B switch
8 - Octasynth

PP Digital
1 - L6 G30
2 - Distortion Pro
3 - Mini Vent 12v
4 - H9 9v

I ended up like so:

PP2
1 - wah
2 - tuner, SP Comp, A/B Switch - daisy chained
3 - Klon
4 & 5 - Distortion Pro - current doubler cable
6 & 7 - EHX B9 - current doubler cable
8 - Octasynth

PP Digital
1 - L6 G30
2 - Switch Dr
3 - Mini Vent 12v
4 - H9 12v

A lot of things helped and I have a much better noise floor now, but there's still changes to be made. Isolating the Source Audio Classic Distortion Pro from the Eventide H9 helped keep those clocks quieter as they're being few power from different supplies now. Also, switching the H9 to 12v instead of 9v seems to have had some benefit, since engaging the H9 adds less noise to the signal now. The current doubling may or may not have had any positive impact, but I had the cables sitting around, so I figured why not?

The only issue I have now is that engaging the SP comp adds some noise. I think it was a mistake to daisy chain the SP with the A/B and tuner. I might isolate the SP and daisy chain the Klon instead, since I'm using it for a solo boost and any background noise it makes when engaged won't be noticed. 

Without the SP comp engaged, I couldn't hear ANY noise on the line, even with the amp up at show volumes.

Rehearsal is tomorrow, so we'll see how it goes!


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## Dorian2 (Jun 9, 2015)

I had the same type of issue recently with excessive noise using an old Boss DS-1 and an MXR EQ, along with the Polytuner 2. Initially the EQ was in the FX loop of the amp, and the speaker of the amp was making a weird sound (like there was a hole in the speaker is all I can think of....almost like a "flubbing" sound). In the end it all turned out to be the daisy chain I had running it. That was my first and last attempt at daisy chaining power. Removing the chain and plugging a separate supply into each pedal did the trick....although though there is still some noise because they are all plugged into the same outlet.


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## hollowbody (Jan 15, 2008)

Dorian2 said:


> I had the same type of issue recently with excessive noise using an old Boss DS-1 and an MXR EQ, along with the Polytuner 2. Initially the EQ was in the FX loop of the amp, and the speaker of the amp was making a weird sound (like there was a hole in the speaker is all I can think of). In the end it all turned out to be the daisy chin I had running it. That was my first and last attempt at daisy chaining power. Removing the chain and plugging a separate supply into each pedal did the trick....although though there is still some noise because they are all plugged into the same outlet.


Yeah, I'll have to find a compromise that works for me. I can't use another PSU as I'm already committed to the two I have in terms of finances and the holes I've cut out of my PT1 to fit them all underneath! Hopefully isolating the SP Comp will clean up the last little bit of noise. I'll find out soon!


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## mhammer (Nov 30, 2007)

As someone who is regularly on the DIYstompbox forum (and my buddy for almost 25 years, now), and a former hardware engineer for IBM, RG Keen designed the Truetone 1-Spot Pro to be immune to digital whining from interacting pedals. It's not an _impossible_ feat; you just need to deliberately design for it. I'm sure other companies will provide similar products eventually. RG and Bob Weil just got out of the gate quickly. Not cheap, but VERY robust.


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## hollowbody (Jan 15, 2008)

mhammer said:


> As someone who is regularly on the DIYstompbox forum (and my buddy for almost 25 years, now), and a former hardware engineer for IBM, RG Keen designed the Truetone 1-Spot Pro to be immune to digital whining from interacting pedals. It's not an _impossible_ feat; you just need to deliberately design for it. I'm sure other companies will provide similar products eventually. RG and Bob Weil just got out of the gate quickly. Not cheap, but VERY robust.


The CS12 seems like it would have been a very solid choice for me, especially given what you're saying about it's rejection of digital whine. If I can't get my VL PSUs to do the trick, I'd definitely consider selling them and moving to a single CS12.


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## High/Deaf (Aug 19, 2009)

hollowbody said:


> The only issue I have now is that engaging the SP comp adds some noise. I think it was a mistake to daisy chain the SP with the A/B and tuner. I might isolate the SP and daisy chain the Klon instead, since I'm using it for a solo boost and any background noise it makes when engaged won't be noticed.
> 
> Without the SP comp engaged, I couldn't hear ANY noise on the line, even with the amp up at show volumes.
> 
> Rehearsal is tomorrow, so we'll see how it goes!


Does your tuner have an isolated power out? Daisy-chaining the A/B and tuner and then using the isolated output to the audio box (either Klon or SP) might get that last bit of noise.


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## hollowbody (Jan 15, 2008)

High/Deaf said:


> Does your tuner have an isolated power out? Daisy-chaining the A/B and tuner and then using the isolated output to the audio box (either Klon or SP) might get that last bit of noise.


No, just a 9vdc in on the Polytune Mini. I'm going to swap leads on the SP and Klon tonight before rehearsal and see what it does for me. If that doesn't work, I will try running the B9 from just the high current output and use the extra isolated output for the Klon. From experience, the B9/Mini Vent side of my rig is fairly quiet, so I don't think it had any issues before running off of the 5/6 outputs of the PP2.


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## mhammer (Nov 30, 2007)

I should probably clarify that it is not ALL combinations of digital pedals that produce whining. Rather, it is the combination of the various clocks and clock divisions in the respective pedals that _might_ product audible sums and/or differences. Proper isolation will override such interactions, but even if there IS no isolation, if the clock signals riding on the power lines only produce sums or differences that are well above hearing range, you won't hear anything noisy.


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## hollowbody (Jan 15, 2008)

I'm closing the case on this. Had rehearsal last night and the rig was dead quiet in the same room it was noisy as heck in a couple weeks ago. Looks like the changes I made helped. 

I ended up isolating the SP Comp and daisy chaining the Klon, and that helped as well. Hopefully I can isolate the KTR somehow as well, but that's gonna take some tinkering.

Thanks for all your help and suggestions, everyone!


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## mister.zed (Jun 8, 2011)

Wish I knew if buying this would solve my problems. I guess I could buy, try and return if the hum remains... 

Found this on the Truetone web site and thought it was interesting:

*The 1 SPOT Pro Story*

For many years, Truetone has made musicians’ lives easier with the 1 SPOT, the original compact pedalboard power supply. It works so well that a lot of musicians never felt the need to get one of those brick-style power supplies, and we here at Truetone didn’t see the need for those either, even though they were quite popular. Bob Weil, founder of Truetone, explains:

“A lot of people over the years had told us that we should make a power brick. Even some of my own staff urged me to do it, but I didn’t want to for two reasons. First, I knew the 1 SPOT could power just about every pedal out there, so I didn’t see the need. Second, I didn’t want to make just another knock-off of someone else’s power brick. If we were going to make one, we were going to do it our way and have features that nobody else could offer. As pedal designs changed and it became more common for digital pedals to require isolation and for others to need something other than 9Vdc, I finally saw a reason for us to design a power brick.”

“It took 3 years and lots of experimentation, but we were finally able to design a 1 SPOT Pro, using our own proprietary technology to give musicians all the features they need for today’s pedalboards. The original 1 SPOT still works great for most musicians, but for those who need more power and versatility, the 1 SPOT Pro fills the need perfectly.”


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## mister.zed (Jun 8, 2011)

So after much troubleshooting I determined that my EXH Voicebox was causing my Boss SL-20 to be noisy (and even noisier when the SL-20 was in bypass!). Up until last night I had been powering my entire board with a One Spot wall wart (except for the Timeline which used its original supply). I love the One Spot. Lots of power and low in cost. And simply by changing the EHX Voice Box to a regular old Ibanez wall wart, the noise went away entirely. I'm glad this worked for me as it saved me a couple hundred dollars. If I ever need a more capable power supply I'll go with a Truetone 1 Spot Pro because the original One Spot has been so solid for me and I like to reward good engineering. (And Mark says it was engineered to overcome precisely this problem.) But for now the old One Spot and a second cheap adapter is serving just fine.

I'm just posting this for posterity on the interwebs in case some other Voice Box owner out there is trying to troubleshoot a noisy board.


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## mhammer (Nov 30, 2007)

The Voice Box is a digital pedal. Digital pedals sharing the same power source don't always get along so well. Like The Offspring say: Ya gotta keep 'em separated.


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## mister.zed (Jun 8, 2011)

Exactly. But in this case, separate wall warts was sufficient. No need at this time for a full-on, every output separated, power supply brick.


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## mhammer (Nov 30, 2007)

+1 That's all that's needed in many cases. The expensive super-isolated multi-output brick is for folks who a) don't have the space on-board to accommodate multiple adaptors in a convenient configuration, and b) have the money. But all that is really required to make the whine go away is separate supplies.


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## hollowbody (Jan 15, 2008)

mister.zed said:


> So after much troubleshooting I determined that my EXH Voicebox was causing my Boss SL-20 to be noisy (and even noisier when the SL-20 was in bypass!). Up until last night I had been powering my entire board with a One Spot wall wart (except for the Timeline which used its original supply). I love the One Spot. Lots of power and low in cost. And simply by changing the EHX Voice Box to a regular old Ibanez wall wart, the noise went away entirely. I'm glad this worked for me as it saved me a couple hundred dollars. If I ever need a more capable power supply I'll go with a Truetone 1 Spot Pro because the original One Spot has been so solid for me and I like to reward good engineering. (And Mark says it was engineered to overcome precisely this problem.) But for now the old One Spot and a second cheap adapter is serving just fine.
> 
> I'm just posting this for posterity on the interwebs in case some other Voice Box owner out there is trying to troubleshoot a noisy board.


Glad you found a solution! Usually all it takes is a little fiddlin'-around!


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