Pedal Power

[fclefgeoff]

Sorry. Not my board. Just an example of the FTJr with a Nano......

Ahhh, gotcha. Well, my FT jr arrived yesterday and I have mounted it on the Nano with 3M Dual Lock. It fits great but it does bottom out. However this isn't a problem for me personally because my board sits on top of my amp and acts as a "tonal control center". It is basically a "set & forget" scenario for me. I'll probably attempt to mod the feet for more clearance at some point down the road but it should work just fine for my gig tonite.

You can see the FT touches the floor here.

What is the sound of one hand clapping? Baby Buddha, ya'll.

 

[marijn van gils]

I use the 1-Spot and I KNOW that BOSS stomps are just noisy anyway.

I have a few - BOSS pedals, that is - and when they are out of the loop, the 1-Spot is great - no noise at all.

Put a BOSS pedal in the chain and in bypass especially, there's noise again. So maybe you shouldn't fault the 1-Spot - it might just be the BOSS pedals.

Of course the powersource shouldn't be blamed. But would you choose your pedals to work good with your powersource, or would you rather choose your powersource to work good with your pedals? The last option seems to make more sense to me...

By the way, I'm a happy Voodoolab user. It powers 7 pedals for me. I only have to run my TC electronics Nova Repeater on it's own adapter since it demands too much current for the Voodoolab. A powerstrip mounted on my board makes this a non-issue though.

 

[SurferJoe46]

Of course the powersource shouldn't be blamed. But would you choose your pedals to work good with your powersource, or would you rather choose your powersource to work good with your pedals? The last option seems to make more sense to me...

By the way, I'm a happy Voodoolab user. It powers 7 pedals for me. I only have to run my TC electronics Nova Repeater on it's own adapter since it demands too much current for the Voodoolab. A powerstrip mounted on my board makes this a non-issue though.

I'm missing the logic here.

If your 1-Spot power supply is silent, then how's another good power supply gonna make any difference?

 

[krstko]

I don't even get how a power supply can make noise?

 

[SurferJoe46]

They might have inferior circuitry that isn't well filtered output. That will induce some hum - but 'noise' like RFI may just be a product of the power cables being good antennas too.

I know that I have quite a lot of extra wire that I have to coil up, and if it's near a Cry Baby, it induces some nasty sounds.

I've tried to wind the excess in figure eights, and that helps a lot.

 

[marijn van gils]

I'm missing the logic here.

If your 1-Spot power supply is silent, then how's another good power supply gonna make any difference?

The power supplies don't make noise at all, and neither do the pedals by themselves (normally...), but grounding issues between te pedals can cause noise. By using isolated power outlets, these grounding issues can be eliminated. The pedalpower plus 2 has fully isolated outlets, daisy chaining from a 1-spot does not.

Therefore, neither power supply nor pedals should be "blamed", but their combination might just not work good. Using a power source with isolated outlets prevents these issues. It is more expensive, but I haven't had any hum yet, even with boss pedals...

This was my logic:
I choose my pedals for their sound, features, size, quality, ... and then I make sure I have a power source that works well with them. Doing it the opposite way, i.e. limiting my choice of pedals because they have to fit my powersource, would seem illogical to me.

 

[bongomania]

^^^ FACTS.

 

[SurferJoe46]

^^^ FACTS.

OK, bongo - that's fair ---- but ya gotta explain a little more than just ditto-ing the answer.

I contend that my BOSS pedals on 9VDC battery are quiet, whereas the same pedals on a single or multiple outlet power supply can be noisy even in 'true bypass mode'.

I can chain a few effects and all is well until I add a BOSS almost-anything in the circuit. It sounds like poor quality white noise.

 

[bigchiefbc]

I'm gonna go ahead and throw in my own situation in this thread. So, I'm in the process of downsizing my covers board, which should enable me to fit on a PT Pro, and use my homemade board for my originals band. Moving to a PT means that I'll need a power supply.

The biggest problems with finding a supply are that I need:

1 9VAC output for my Whammy
2 relatively high-current outputs for my Octavius Squeezer (250-300 mA) and my DD-20 (200 mA)
1 isolated 9V output for my wah (Wilson Freaker, which is positive ground)
the rest of my pedals could all be daisy chained off a standard output.

Now, the only supply I've found so far which has a 9VAC output for the whammy and two outputs high enough for the Squeezer and the DD-20 is the Cioks AC-10. Does anyone know of any others?

 

[bongomania]

OK, bongo - that's fair ---- but ya gotta explain a little more than just ditto-ing the answer.

I contend that my BOSS pedals on 9VDC battery are quiet, whereas the same pedals on a single or multiple outlet power supply can be noisy even in 'true bypass mode'.

I can chain a few effects and all is well until I add a BOSS almost-anything in the circuit. It sounds like poor quality white noise.

OK, it's just that I've posted the same explanatory details dozens of times already. Here's the full explanation:

It's all about ground planes and differences in potential. A ground plane is the common wiring, which acts as "zero volts", and it not only includes the common ground on the circuitboard and from the power supply, but also the neg connector of the in/out jacks, and very often the metal housing of the pedal itself, as well as any metal knobs and switches. Because the jacks are part of this, the ground plane of any one pedal is also in common with the ground plane of any pedal it's connected to via patch cords. Additionally since you're using a daisy-chain supply, all the pedals have their grounds connected that way too. So it's a big messy loop, with every pedal affecting every other pedal.

"Potential" is a difference in voltage, so for example the only reason a circuit sees 5V at one component is because there is a 5V difference in potential between that part at that moment, and the ground plane. There's actually no such thing as zero V in a powered circuit--it's just a reference point.

When two devices are designed so their ground planes are not identical, there is a potential between those two planes--even though internally to each pedal the ground is "zero V"! When the is a difference in potential between two planes, there is voltage, and this voltage has nowhere to go, and it takes the path of least resistance, which very often means it leaks into the audio path as noise.

Even switching a pedal on and off can change the potentials, as the path of least resistance changes. So a pedal can be silent when "off" and noisy when "on", or the other way around!

And as often as not, the pedal that acts noisy isn't even the one with a problem. Just because the noise leaked into the audio path of pedal A, it could still have been pedal B that had the odd-man-out ground plane among the various pedals on the board.

<snip>
It's the daisy chain connections from the supply that complete the main loop through which the noise travels. Isolating the power for each pedal breaks that loop, reducing or eliminating the noise in most (not quite all) cases.

To be clear, it's not the wart itself that is "isolated", but rather the pedals that need their power isolated from other pedals. So you can do that by using batteries, or separate wall warts for the "problem" pedals, or buying a brick-shaped supply with isolated outputs like the Voodoo Labs PP2. Note the Dunlop Brick does NOT have isolated outs.

So to spell it out, when you are powering the Bosses with batteries, their supplies are isolated. When you use a daisy chain, potentials are created (with some pedals, not all) that result in noise. It's not specific to Boss, and it's not even that the specific ones you have are noisy. It's the system altogether that's noisy.

 

[SurferJoe46]

Does your statement then mean that 'isolated' systems are multi-transformered?

Or - do the wires on those units all just individually return to a common rail inside the brick?

I know I worked on isolation transformers in every room in a hospital (know WHY aspirin and q-tips cost $90.00 each?).

The idea was to eliminate impossibly small electrical imbalances from one room to another and also to the floor to keep doctors and nurses when touching a patient from generating a spark (Yes - patients explode and it's messy and a lot of paperwork).

So isolated power supplies aren't foreign to me - I just wonder about the circuit, that's all.

 

[krstko]

I finaly understand what's the point of isolated power supplies
now I only need to figure out mA's

 

[boomertech]

Does your statement then mean that 'isolated' systems are multi-transformered?

Or - do the wires on those units all just individually return to a common rail inside the brick?

Power isolation can be individual transformers or one transformer with a single primary and multiple secondary coils. With transformers, the primaries are not isolated from each other but the secondary outputs are isolated from each other. There are also iso-pumps that are used with DC power that will give you power isolation.

Some pedal manufacturers insert resistors, diodes or both in the power supply ground. What happens when these pedals are daisy-chained powered together, the signal ground turns into a path for the returning ground current to the power supply through the pedal(s) with the least resistance. If this creates a problem it is sometimes hard to determine what pedal is the offender. The pedal with the resistance in the power ground is the offender, but the issue may show up in another pedal that has no resistors in the power ground… because that pedal is now providing the power ground for itself and the offender.

If you have access to an OHM meter you can check this by measuring from the power jack ground pin to the signal input jack ground. Pedals with zero ohms (or very low resistances) will have a better chance of being chained together without issues than the pedals that have resistance.

-Frank

 

[alec]

I currently power all my pedals from a 1Spot. Adding an EHX Freeze to the loop can introduce noise, but it varies depending on where in the loop it is.
Would isolated power fix that or is it something else?

 

[SurferJoe46]

Power isolation can be individual transformers or one transformer with a single primary and multiple secondary coils. With transformers, the primaries are not isolated from each other but the secondary outputs are isolated from each other. There are also iso-pumps that are used with DC power that will give you power isolation.

Some pedal manufacturers insert resistors, diodes or both in the power supply ground. What happens when these pedals are daisy-chained powered together, the signal ground turns into a path for the returning ground current to the power supply through the pedal(s) with the least resistance. If this creates a problem it is sometimes hard to determine what pedal is the offender. The pedal with the resistance in the power ground is the offender, but the issue may show up in another pedal that has no resistors in the power ground… because that pedal is now providing the power ground for itself and the offender.

If you have access to an OHM meter you can check this by measuring from the power jack ground pin to the signal input jack ground. Pedals with zero ohms (or very low resistances) will have a better chance of being chained together without issues than the pedals that have resistance.

-Frank

Thanks - copied and printed.