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Topic: Noise in the Pedalboard Power Supply |
Jon Light
From:
Saugerties, NY
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Posted 14 Nov 2014 8:23 am |
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I have a board with a bunch of good quiet stomp boxes and one old Holy Grail that has reverse polarity (tip pos) from all the other more modern, standard tip neg boxes.
If I run the Grail on a separate power supply everything is quiet. If I run it on a daisychain with the rest of the units with an adapter cable for proper polarity there is a high pitched whine in the audio signal. Not screaming--just background noise but annoying.
Does this bring to mind any sort of simple generic fix to filter/isolate this noise out of the power supply?
Anything more involved than introducing a resistor or diode will be more than I'm willing to try. I'll just go with the extra wallwart. |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 14 Nov 2014 9:44 am
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I get this sometimes with some pedals, typically digital pedals with either a digital processor inside (reverb, etc.) or with an internal voltage charge pump. My solutions has always been to give the culprit pedal its own wall wart. Something in the offending pedal seems to leak that clocking, switching, or processing noise back into the power supply and that gets into the audio thru the daisy chain power or the common power supply. It's the only fix I've come up with so far.
B |
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Jon Light
From:
Saugerties, NY
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Posted 14 Nov 2014 10:11 am
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Ah. That good old strange comfort that you get when if you don't get a solution, at least you find out that you are not alone.
Thanks Brad. |
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Tim Marcus
From:
San Francisco, CA
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Posted 14 Nov 2014 10:18 am
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this is why they sell isolated power supplies
_________________
Milkmansound.com |
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Jon Light
From:
Saugerties, NY
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Posted 14 Nov 2014 10:34 am
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Yeah--this board is supposed to be smaller than my monster board--more grab & go-y. I was resisting power supplies beyond a One Spot.
Unfortunately the board has already grown too deep to be powered by the Volto---too much digital draw for the life of the V's charge. Why can't my minimal stay minimal? |
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Chris Walke
From:
St Charles, IL
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Posted 14 Nov 2014 1:13 pm
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| Jon Light wrote: |
Yeah--this board is supposed to be smaller than my monster board--more grab & go-y. I was resisting power supplies beyond a One Spot.
Unfortunately the board has already grown too deep to be powered by the Volto---too much digital draw for the life of the V's charge. Why can't my minimal stay minimal? |
I recently got a OneSpot with the daisy chain and noticed the same thing - a high pitch whine. Switched back to batteries and it's fine. Have yet to take the time to eliminate the problem pedal(s). I've been told that anything that manipulates time - delays/reverbs/etc are generally the culprits.
Interestingly, I also run a Holy Grail on my board. Guess when I go thru the pedals, I'll start there. |
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Jon Light
From:
Saugerties, NY
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Posted 14 Nov 2014 1:36 pm
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As you can see from my initial post, my focus was on the polarity thing. It may not be the issue at all.
I've run a lot of scenarios including isolating signal paths of different pedals in loopers and the results seem conclusive--it has nothing to do with signal path. It is 100% about the power path and the Holy Grail is the culprit. And isolating the power is the solution.
This particular board has two other digital pedals--El Capistan and Line6 RotoMachine. Removal of neither makes a difference. |
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Matt Bush
From:
Portland, OR
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Posted 14 Nov 2014 5:02 pm
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| You might also try a different adapter between the 1-Spot and the Holy Grail. It's possible that there's an issue with the adapter. |
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Jon Light
From:
Saugerties, NY
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Posted 14 Nov 2014 5:26 pm
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| Yeah--I've been through a whole bunch of different wiring schemes. The whine seems pretty universal. |
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Les Cargill
From:
Oklahoma City, Ok, USA
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Posted 14 Nov 2014 8:05 pm
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This might be from left field, but ...
There's a product called the Pedaltrain Volto that is essentially a laptop battery regulated down to 9V for pedal powering. |
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Lane Gray
From:
Topeka, KS
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Posted 14 Nov 2014 11:05 pm
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If it takes a normal connector but reversed polarity, I think I'd open it up and swap the wires between jack and board, so it'll how up the same.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Jon Light
From:
Saugerties, NY
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Posted 15 Nov 2014 6:06 am
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The Volto has two outputs but they are not isolated. If I run the Grail from one ouput and the rest of the board from the other the whine is still there. But with three digital pedals on the board, the Volto's charge life is a bit short anyway. It is very impressive with a board full of dirt boxes etc. with low draw but with boxes in the higher mA range it drains a lot faster.
However if I just run the Grail with the Volto and the rest of the board from the One Spot it is indeed a decent alternative to using two warts and is probably the best of my options.
You can never flip a box's power supply polarity without addressing common grounds in the signal path (jacks, etc.). |
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Rob Fenton
From:
Toronto, Ontario, Canada
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Jon Light
From:
Saugerties, NY
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Posted 15 Nov 2014 8:27 am
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| Thanks. They weren't on my radar. |
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Stephen Cowell
From:
Round Rock, Texas, USA
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Posted 15 Nov 2014 9:10 am
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You need to filter the voltage going to the Grail... not for the Grail, but for the other pedals. The filter will stop noise from going back through the PS wires to the other pedals.
Simplest filter is a big capacitor across the PS... put a 220uF electrolytic across them (at or inside the Grail) and see what you get. The cap is polarized, so observe polarity or it'll go up like a firecracker and you'll say bad words (don't ask how I know). Here's one that will work fine:
http://www.radioshack.com/220uf-35v-20-radial-lead-electrolytic-capacitor/2721029.html
_________________
New FB Page: Lap Steel Licks And Stuff: https://www.facebook.com/groups/195394851800329 |
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Jon Light
From:
Saugerties, NY
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Posted 15 Nov 2014 10:09 am
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Interesting, Stephen. Thanks.
I think a list of those words would be valuable to those of us who have probably never heard them. |
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Lane Gray
From:
Topeka, KS
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Posted 15 Nov 2014 12:57 pm
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Jon, this is primarily a pedal steel forum: I think we all went through those words learning how to move the bar, pedals and knee levers at the same time!!
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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