Power Supply Isolation

[outoftune]

Hello everyone. I am making a power supply for pedals that will be built in to a loop selector. I pretty much was planning on making the standard 8 outputs 9VDC 100mA per output. My question is, how necessary is it to isolate the outputs or can they all be on the same supply?
Also any recommended transformers or regulators would be helpful too.
Thanks.

[outoftune]

Any opinions/knowledge to share?

[aziltz]

i've never built one, but i do know that making isolated outputs involved a transformer with 9 sets of coils, and probably won't fit in a looper box.  (Think the size of the Pedal Power 2+ or BBE Supa-Charger).  Each output has its own current rating (200mA for example)

Un-isolated outputs however, its basically the same as a daisy chain.  8 Outputs in Parallel, essentially.  Simpler to implement, but less flexible.  Each output is linked together drawing off the same power/current supply, essentially in series (500mA total for all 8 combined for example)  This won't make noise any better and won't let you use it with reverse polarity pedals (like a fuzz face or the like).


I hope that helps.

[Sir H C]

With isolated outputs you can have positive and negative ground pedals all using plugs without issues.  Also this isolates the grounds preventing ground loops.

[outoftune]

Thanks for the reply. I realize that it has the potential to be noisier. I guess I would like to make something similar to what is on the furman and skb pedal boards http://www.furmansound.com/product.php?id=SPB-8
It states: Eight individually protected 9VDC outlets, with 8 included power cords
Individually protected probably just means that they have a poly fuse on each output. If it was isolated it would say so. I don't know, I guess somebody's input who has build power supplies for pedals would be helpful.

[aziltz]

Thanks for the reply. I realize that it has the potential to be noisier. I guess I would like to make something similar to what is on the furman and skb pedal boards http://www.furmansound.com/product.php?id=SPB-8
It states: Eight individually protected 9VDC outlets, with 8 included power cords
Individually protected probably just means that they have a poly fuse on each output. If it was isolated it would say so. I don't know, I guess somebody's input who has build power supplies for pedals would be helpful.

yeah, those aren't isolated.  its like having a MXR DC Brick built into the pedalboard.

[petemoore]

All power and signal jacks are insulated and isolated, eliminating noisy ground loops .
  I built a Spyder into an old power supply box from a computer.
  I bought a VoodooLabs PPII, like the Spyder it has 8 isolated outputs [no ground, just floating voltage potentials].
  Each one has a secondary Transformer winding, rectification, filter and regulation.
 

[aziltz]

All power and signal jacks are insulated and isolated, eliminating noisy ground loops .

 

Not sure what you're referring to exactly.  Is that from the Furman site?

  I built a Spyder into an old power supply box from a computer.
  I bought a VoodooLabs PPII, like the Spyder it has 8 isolated outputs [no ground, just floating voltage potentials].
  Each one has a secondary Transformer winding, rectification, filter and regulation.
 

I agree.  I think the OP was asking how that was different from the DC brick type PS, which is basically a daisy chain in a box, and is not isolated.

[petemoore]

  I read the Furman as having multiple secondary taps = isolated outputs.