Noise Issue with ISO 5

[JamesJeh]

My pedalboard patch cables are carefully built and everything is sounding clean with batteries.

When I connected my Voodoo Lab Pedal Power ISO-5 I heard a super nasty hum. If I move the ISO-5 far away from the pedals (can only go so far with all those short DC cables) the noise goes away. It's got to be about 8" away from ANY of the pedals to fully remove the noise. But my board, like many, is totally cram-packed and I don't wanna use a huge pedalboard just to add space between the ISO-5 and the nearest pedal.

I'm pretty sure the noise isn't ground loop (obviously they are isolated outputs) but EMI coming off the transformer inside the pedal power. It gets worse when I bring the Pedal Power near to the pedals, so...Kind of a bummer since the whole reason I got it was to keep things quiet. Even if I'm using a different power supply for the pedals, bringing the ISO-5 physically close to any of the pedals produces a hum (as long as the ISO 5 is connected to the 120v power)

So next I tried a 10-spot daisy chain (Pig Hog brand, nice thick cables) and chained all the pedals together with the daisy chain cable. I then tried connecting it to 2 different cheap power adaptors with sufficient current. HUGE buzz with both adaptors, more of a ground hum type sound. No surprise there.

So next I tried connecting the daisy chain to the 400ma output on the ISO-5, keeping it far away from the pedals (all pedals daisy chained together and connected to ONE output on the ISO-5). This actually seemed QUIETER than using the isolated outputs for each separate pedal. Probably because I was able to keep the ISO-5far far away from the pedalboard. This tells me I probably don't have to worry about ground loop noise if the power supply is clean and far away from any pedal.

The ISO 5 was certainly the cleanest/quietest AS LONG AS I kept it 8 or 10 inches away from any of the pedals...but I'd really like to have it mounted to my board.

I figured it was just EMI coming off the transformer inside the ISO 5. But nobody else seems to be complaining about this, and after I posted about this issue on another gear forum, somebody suggested this isn't normal and I should contact VooDooLab.

Thanks

[JohnClark]

We will gladly inspect your ISO-5. Feel free to give us a call or write to info@voodoolab.com to arrange for an RMA if you would like.

Have you tried powering just one pedal at a time to find if there is perhaps a main offender in the bunch? What pedals are you powering?

[JamesJeh]

We will gladly inspect your ISO-5. Feel free to give us a call or write to info@voodoolab.com to arrange for an RMA if you would like.

Have you tried powering just one pedal at a time to find if there is perhaps a main offender in the bunch? What pedals are you powering?

Thanks for the reply.

Korg Pitchblack tuner--> EHX Octave Multiplexer--> MXR Phase 90--> HBE Power Screamer (overdrive)

When I power all 4 pedals on batteries and all pedals OFF (ISO-5 not even connected to pedal, just powered by AC cord), I can bring the ISO-5 close to the tuner, octave or phase 90 and I get a loud hum. I get a minor hum bringing the ISO-5 close to the overdrive pedal. When I turn on the overdrive, and bring the ISO-5 near it, it now too produced the loud hum. Again this is with the ISO-5 not even connected to any of the pedals.

The hum is worse when I face the bottom of the ISO-5 toward the pedals, the sides and top aren't as bad but still present.

I'll contact support through the email provided, thanks!

[JamesJeh]

I just wanted to follow up and say that I sent in the ISO-5 and I really really appreciate the customer service. Fast, prompt with clear instructions for the shipping. I hope I haven't wasted Voodoo Lab's time though, as I just bought a brand new Pedal Power Plus from Sam Ash (adding more pedals over the next couple weeks), and it's doing the exact same thing. Different guitar, different arrangement of pedals (some the same), different cables, and different amp. but it's doing the exact same thing. I'll just work around it and build a larger board to set the power supply several inches form the pedals.

I'd like to pay for the return shipping on the ISO-5 as it's probably not broken. I guess it's just the "nature of the beast" with transformers. If I put it about 5" or 6" away it's fine. Can't have it right next to the pedals.

I see on pedalsnake.com it says:

"Any power supply will emit a certain amount of electromagnetic interference (EMI). When placed to close to an effects pedal, you can hear the effects."

when moving the unit close to the pedals, Power Screamer is the worst, Phase 90 second worse, BOSS CS-3 has moderate noise, CE-2 (running at 12v) has barely noticeable noise, Korg tuner has no noise.

Power is super clean and quiet once I move the unit away from the pedals. I'm not dissatisfied with the products, just sorry I wasted somebody's time. I plan to keep the Pedal Power Plus, this is NOT a complaint!

[Akio]

I noticed that the 400 mA output will give more hum on Boss CS-3 or Phase 90 than the three other isolated output . I also noticed that when CS-3 is feeded alone by EBS 1000 mA, hum is even lower .

[datwungai]

I have the same issue with my ISO 5. If I get my Analogman DS-1 Pro, Cali76 CD, my TCE PolyTune or any Mogami cables anywhere close to the ISO 5, my signal goes right down the toilet (EMI sucks most of the signal to ground).

Not trashing Voodoo here, (I've used and been very happy with the Pedal Power 2 Plus for years) but with the 9 pedals I have, and their high current requirements, plus the new EMI I've discovered by adding the ISO 5 to the PP2+, I'm probably going to look for a different solution. The effect of the EMI is so severe that I struggle to understand why it passed basic testing and was put into production.

Again, Voodoo makes some great stuff - I'll probably be buried with my sparkle drive - but the power supply situation I have, such as it is, warrants an update. I need more than one or two high current outputs and don't want to sacrifice outlets to jumper two together to get it.

Still a Voodoo Labs fan, will still use their products, just not for power supply.

[JohnClark]

I have the same issue with my ISO 5. If I get my Analogman DS-1 Pro, Cali76 CD, my TCE PolyTune or any Mogami cables anywhere close to the ISO 5, my signal goes right down the toilet (EMI sucks most of the signal to ground).

Not trashing Voodoo here, (I've used and been very happy with the Pedal Power 2 Plus for years) but with the 9 pedals I have, and their high current requirements, plus the new EMI I've discovered by adding the ISO 5 to the PP2+, I'm probably going to look for a different solution. The effect of the EMI is so severe that I struggle to understand why it passed basic testing and was put into production.

Again, Voodoo makes some great stuff - I'll probably be buried with my sparkle drive - but the power supply situation I have, such as it is, warrants an update. I need more than one or two high current outputs and don't want to sacrifice outlets to jumper two together to get it.

Still a Voodoo Labs fan, will still use their products, just not for power supply.

Sorry to hear you too are having troubles. We certainly would love the chance to check your ISO-5 out. Feel free to give us a call or write to info@voodoolab.com so we can arrange a return.

That said, the noise the OP was experiencing was a loud buzz, but you what you describe as "sucks most of the signal to ground" I would interpret as you are getting an overall signal level drop rather than a loud buzz.

p.s. If it is a buzz, and you are hearing it even with just cables close to the unit, I would first check that the shield connections on your cables are sound.

[Bitmann]

Hi!
I also use Voodoo ISO5 .
My amp makes a very loud pop/thump when I insert the cable into the input. It doesn’t matter if the amp’s volume is turned down or up, the thump always has the same loudness. I know some basics about amp electronics and soldering, so fire away
Thanks, Bitmann

[JohnClark]

Hi!
I also use Voodoo ISO5 .
My amp makes a very loud pop/thump when I insert the cable into the input. It doesn’t matter if the amp’s volume is turned down or up, the thump always has the same loudness. I know some basics about amp electronics and soldering, so fire away
Thanks!

Most likely it is one or more of the pedals that is doing this but if you have a tube amp, I'd say leave it on Standby until you have powered up the pedalboard. If it is a Solid State amp simply power it up last.

Is your amp properly connected to the AC mains ground?