Question about power Daisy Chaining

DrGonzo

HEy dudes n dudettes

I'm just wondering about Noise issues when daisy chaining devices from one power supply.
Is there any way to avoid this?

I'm running a bit low on cash now and might need to sell my BBE power supply for now.. but i did notice I get a bit more noise when running my pedals in a daisy chain...

Does pedal order in the chain matter? like maybe first Analog then Digital... i only have 2 analog pedals... a overdrive, fuzz and wah, the rest are all digital - DD3, RV5 and line 6 M5
I have 2 Roland 2A power supplies that i use

If i cant make it better then i will see if i can sell something else besides the BBE and keep that.

Thanks in advance

peterleroux

DrGonzo wrote: Does pedal order in the chain matter? like maybe first Analog then Digital...

No ☹ Effectively a normal daisy chain is a parallel circuit, so the order you connect them on the chain doesn't matter. I've never tried it but a ferrite bead might cut some of the noise down (those round 'clamp' things you sometimes see on computer or TV cables). In general the solution is to put analogue and digital effects onto separate circuits, like using one of your power supplies for each (if the three digital pedals use less than 2 amps)

AlanRatcliffe

Mostly down to earth loops and a little bit to ripple in the power supply. Good power supplies have extra smoothing and isolated outputs. Short of having a good supply or putting isolation transformers between each effect, the best cure is to have a few patch cables that are signal only (ground connected on one side only for screening) to break the loops where you have them.

DrGonzo

peterleroux wrote:
DrGonzo wrote: Does pedal order in the chain matter? like maybe first Analog then Digital...
No ☹ Effectively a normal daisy chain is a parallel circuit, so the order you connect them on the chain doesn't matter. I've never tried it but a ferrite bead might cut some of the noise down (those round 'clamp' things you sometimes see on computer or TV cables). In general the solution is to put analogue and digital effects onto separate circuits, like using one of your power supplies for each (if the three digital pedals use less than 2 amps)

Good suggestion thanks Pete.. will try this just now..
All my digital pedals will draw a Max combined 640mA of power and the power supply has 2A of power.
and i have 2 so i will feed the other one to my analog pedals and see how that works out.

Gearhead

I'm with Alan on this one (I know, boring eh), the ferrite will not do audible things and splitting analogue and digital even less but breaking the ground loop will.

DrGonzo

Alan Ratcliffe wrote: Mostly down to earth loops and a little bit to ripple in the power supply. Good power supplies have extra smoothing and isolated outputs. Short of having a good supply or putting isolation transformers between each effect, the best cure is to have a few patch cables that are signal only (ground connected on one side only for screening) to break the loops where you have them.

Excuse my Noobishness, but im not sure I really understand what you mean? what do you mean by ground conecting on only one side?
Where are the patches 'breaking the loops' situatued on my pedal board..>

Arggh cant wait till I can do the next intake of the Coursera course in practical electronics so i can understand better what you guys are talking about!

AlanRatcliffe

Ground/earth loops are caused by a system being grounded at more than one point, forming a loop that acts as an antenna for noise. Breaking one of the ground connections is the way to cure them (which is why a lot of pro audio gear has "ground lift" switches). On a pedalboard the loop is between the audio ground and the power ground, so you break one of them - and usually the audio ground is the easiest.

So take a patch cable and clip the earth off one side of the cable, in the plug. The ground between pedals is still connected via the daisy chain, so audio still flows, but the loop is gone. Usually you can find the one unit causing the loop and just use lifted patch cables on either side.

Some graphics I made a while ago:

Two pedals with separate power supplies. Audio and power ground are connected, but there is no loop.

With a single supply a loop is formed between the ground points.

Shibbibilybob

To elaborate on what Alan said.
If you have a system that is grounded at more than one point, but the potential at those points is not identical, then some current will flow between the two, effectively making your ground point into a conductor. This conductor is susceptible to induced currents from the voltages on other systems around them (effectively making an antenna). The stray currents in your earth loop manifest as hisses, pops and general noise.
So, as Alan said, try to remove any earthing on your patch cables and have the entire system seeing only your supply earth as being earth.

DrGonzo

:goodtimes: :goodtimes:

Super informative posts, thanks guys!

Thank, you as always GFSA for making my life alot easier!

Will check that out right now.

DrGonzo

Question!: Is there any practical electronics courses that you know of locally?

hint hint nudge nudge... If not, maybe, Alan and/or other knowledgeable chaps on this forum should think about hosting one

One being talloired slightly towards guitar and pro audio would be best, but just the basics would be great.