Powering Dual Pedals - Best Approach Needed

Dirty_Boogie

Dirty_Boogie

Well-known member
I'm about to start boxing my dual Victory (Cetus and John) pedal, controlled by PedalPCB intelligent relay boards. That means 9V needs to go to 4 boards in the enclosure. Since both pedal circuits use charge pumps to goose the voltage up to 18V, and I have an inherent distrust in charge pumps, due to the noise/whining they tend to introduce, I'm trying to figure out the best way to wire this pedal. I will be configuring the intelligent relay for A/B switching (like an amp's channel switching), so both pedals will never be used at the same time, which would reduce total pedal noise. With my Truetone 1-Spot power supply, I know that if I feed individual pedals with their own isolated 9V line, I'm getting the best possible power isolation and filtering. But, for this multi-pedal, that means I'd need to use at least 3 9V lines (1 each for the pedal PCB's, and 1 shared for the relay boards), which I'd rather not do. Other than wiring the power as shown below, or going with something that is going to take up a lot of space and add cost (http://www.muzique.com/lab/9v_iso.htm), any other best practices or approaches inside of the enclosure to perform some level of separation or filtering?
1680699925745.png ,
 
Running the four boards off of a 1-spot going to the single jack isn't any different than running four separate pedals off of a 1-spot and a daisy chain cable. The two preamps have a pretty normal amount of power filtering built in, and I can't imagine anything in there eating enough power to tax the 1-spot at all.

Maybe be mindful of where the wires end up crossing over etc but otherwise, short of adding 3 more dc jacks and using 4 outlets on an isolated pedal power brick thingee, I think it's probably fine as-is.
 
Thanks MDC, and yes, power wire routing is important. I'm typically not a fan of daisy-chaining power off a single 9V wall-wart. That's why I splurged on the 1 SPOT PRO CS12 12-output isolated power supply. When daisy-chaining, or using a cheap 8-output Donner power supply, there was definitely interaction between pedals with charge pumps (e.g., LFO from one "off" pedal, causing another to have a pulsating whine) - solved with the CS12. Just trying to think of ways to mitigate any potential issues, before I start drilling holes. ;-)
 
Looking on the website these circuits only draw about 18ma of current. I’m not sure what the intelligent relay board draws in terms of power but this whole set up is probably close to or lower than 100ma so no issues combining to one jack.
 
Dirty_Boogie said:
Thanks MDC, and yes, power wire routing is important. I'm typically not a fan of daisy-chaining power off a single 9V wall-wart. That's why I splurged on the 1 SPOT PRO CS12 12-output isolated power supply. When daisy-chaining, or using a cheap 8-output Donner power supply, there was definitely interaction between pedals with charge pumps (e.g., LFO from one "off" pedal, causing another to have a pulsating whine) - solved with the CS12. Just trying to think of ways to mitigate any potential issues, before I start drilling holes. ;-)
Click to expand...

Ah, gotcha - I didn't realise truetone uses the "1-spot" name for everything (I thought it was just the single wall wart). If you run the 4 boards inside this box to a single isolated supply outlet you should be fine; I don't think there's anything *inside* the box that should cause clock ticking / LFO sounds.
 
JamieJ said:
Looking on the website these circuits only draw about 18ma of current. I’m not sure what the intelligent relay board draws in terms of power but this whole set up is probably close to or lower than 100ma so no issues combining to one jack.
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Thanks. I know I'll have no problem with the current draw - the question was more about potential power-supply induced noise, due to the nature of these circuits.
 
You could alway solder a larger cap to the jack itself. See if that filters any more of the noise if it happens. Maybe a 220u?
 
This is a tangential question/comment. Why is DC power line routing important? (By “routing,“ my assumption is the placement of wires, not the organization of distribution of power.)

AC power, absolutely. But I’m not aware of DC power (low voltage and amperage) creating any fields, etc. that should affect anything. However, I’m really not knowledgeable about this, hence my question.
 
Alan W said:
This is a tangential question/comment. Why is DC power line routing important? (By “routing,“ my assumption is the placement of wires, not the organization of distribution of power.)

AC power, absolutely. But I’m not aware of DC power (low voltage and amperage) creating any fields, etc. that should affect anything. However, I’m really not knowledgeable about this, hence my question.
Click to expand...
It's my understanding that wire carrying power should never be run alongside a signal line - e.g., don't run the power and the signal input or output wires together. The effect of this might be minimal, but in a high gain circuit, especially where you're not using shielded wiring, additional noise can be picked up. And if the wires must cross, do it at 90 degrees.
 
Dirty_Boogie said:
It's my understanding that wire carrying power should never be run alongside a signal line - e.g., don't run the power and the signal input or output wires together. The effect of this might be minimal, but in a high gain circuit, especially where you're not using shielded wiring, additional noise can be picked up. And if the wires must cross, do it at 90 degrees.
Click to expand...
I can vouch for the shielded wire, especially in high gain circuits. I used it on the input wire primarily and tamed the noise down to an acceptable level.
 
BuddytheReow said:
I can vouch for the shielded wire, especially in high gain circuits. I used it on the input wire primarily and tamed the noise down to an acceptable level.
Click to expand...
But is that noise coming from the dc power lines, or from ac (music or possibly digital on/off cycling, or charge pump) sources in the pedal? I’m not arguing that there is not a noise component in the dc power sources that we use for our pedals. There is, and it does ride along, and eventually get amplified with our signals. But I don’t believe that close proximity to dc current flow, at this level of current flow, will affect, in any meaningful way, signals.

I asked my son, who is a PhD particle physicist at UC Berkeley, about this, this AM. His initial reply was “I’ve never been careful about where I keep DC rails.” But then he asked if we were running more than 30 amps, and what I meant by close proximity. (It took him 5 different times to explain what his research is about to me, when he first started In this. Let’s just say that his instrumentation is sensitive to an order I have difficulty conceiving of.)

I don’t intend to come off as argumentative, I would simply like to resolve whether this is a concern or not. Possibly @Chuck D. Bones, or someone else with trained experience behind their understanding, could join in. I will appreciate being told I’m wrong.
 
Just for "shits and giggles" (as he used to say), here's a photo of what my son's lab looks like. Basically, he "captures" particles in a chamber that has two laser beams, 180 degrees out of phase, as a trap. His capture window is around 4 pico seconds. The lab has two 8 foot high 19 inch racks that are nothing but power supplies. Most of the spaghetti is fiber optics, to move lasers around to various places.

DSCF2507_color.jpeg
 
Alan W said:
Just for "shits and giggles" (as he used to say), here's a photo of what my son's lab looks like. Basically, he "captures" particles in a chamber that has two laser beams, 180 degrees out of phase, as a trap. His capture window is around 4 pico seconds. The lab has two 8 foot high 19 inch racks that are nothing but power supplies. Most of the spaghetti is fiber optics, to move lasers around to various places.

View attachment 45643
Click to expand...
Looks like an expensive way to make popcorn...:cool:
 
Alan W said:
Just for "shits and giggles" (as he used to say), here's a photo of what my son's lab looks like. Basically, he "captures" particles in a chamber that has two laser beams, 180 degrees out of phase, as a trap. His capture window is around 4 pico seconds. The lab has two 8 foot high 19 inch racks that are nothing but power supplies. Most of the spaghetti is fiber optics, to move lasers around to various places.

View attachment 45643
Click to expand...
Yup, looks like my pedalboard :cool:
 
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