"Pedal Power Supplies" vs Daisy chain and wall-wart

[MikeH]

Is there any advantage to the $80-$200 pedal power supplies (a la the Voodoo Pedal Power or TRex Fuel Tank) vs just using a Wall Wart and Daisy chain (a la visual sound one spot)?  The obvious disadvantage being 2 to 4 times the cost...

Obviously the voltage is the same, perhaps they provide more current draw?  I'm wondering because I'm expanding my pedal rig and will now be powering 11 pedals and I'm wondering about current being enough from one wall wart.  Although if that is a problem couldn't I solve it by using 2 wall warts (which I have); 5 on one, 6 on the other?

[earthtonesaudio]

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That's the typical advantage to those multi-output supplies. 

[Mark Hammer]

Assuming that the source of one's choosing has sufficient regulation, isolation is a very big consideration.  Indeed, you can almost consider the one as wall-to-pedal regulation, and the other as pedal-to-pedal regulation.  As digital pedals become more prevalent in pedalboards, and start getting manufactured as cheaply as possible, more will find themselves in situations where cost-cutting results in clock noise and other hash finding its way between pedals via the shared power lines.  Under those circumstances, distributed supplies that isolate each output become more important.

Another factor is simply the space one, though I wouldn't downplay it too much.  Daisy-chain cables come with certain assumptions regarding pedal, size, spacing, jack location and pedal-board layout.  Those "hardwired assumptions" may not fit your needs.  In those instances, a distributed supply with several isolated outputs from which you can run tailored power cords (e.g., for that wah with the power jack on the "wrong" side) or even mini daisy-chains, allow you to have a neater pedalboard that needn't force you to compromise on where you position which pedal.  Your pedals should be positioned in terms of where they need to be for YOU, not where they need to be for the cord.  Distributed supplies allow the former more often.

[drk]

you can get alot of noise with daisy chain

[MikeH]

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That's the typical advantage to those multi-output supplies. 

So, all of the power jacks on those power supplies aren't connected in parallel? 

Which would mean each jack has it's own regulator?

[mth5044]

So, all of the power jacks on those power supplies aren't connected in parallel? 

Which would mean each jack has it's own regulator?

Daisy chains they are all in series, regulated in the adapter then sent out to all the pedals. In isolated power supplies, they all branch out from a single source, then regulated, then to the pedal, or atleast thats been my understanding of them.

Edit: oops, forgot that this is what I think he means by

I
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But I won't speak for anyone 

[frank_p]

This is just a guess, but they might use several coils on the secondary of the power transforemer (if there is only one), so there is no electrical contact between the 9V outputs. Just like the Spider described at GEO (if I remember well).

[MikeH]

So, all of the power jacks on those power supplies aren't connected in parallel? 

Which would mean each jack has it's own regulator?

Daisy chains they are all in series

They can't be in series- they wouldn't work then right?  For each plug, all of the positives are connected together and all of the grounds are connected together.  Thats parallel right?

[mth5044]

They can't be in series- they wouldn't work then right?  For each plug, all of the positives are connected together and all of the grounds are connected together.  Thats parallel right?

I dunno man, I only see two wires coming out of my adapters, and unless there are some tiny tiny sheilded wires inside the outside wire (very tiny for like... 8 adapter chain), then there has to be another reason. Perhaps when the plugs arent plugged into something, there is a mechanism inside the adapter that keeps the current going? I see where you are coming from with the parallel thing, it kind of makes sense but... how could they be in parallel 

[MikeH]

Ok- I looked at the spyder and I see what you mean.  Each power output is regulated individually.  So basically, it's likened to using a separate power supply for each pedal- no shared grounds, so no clock noise, no hum (or at least less hum).

As it stands my rig is pretty quiet, but we'll see after I trow 4 more boxes in the mix.  Should I decide to shell out for one in the future; Can anyone attest to the differences between models?  Some are very expensive, others more affordable. 

[Zedmin_fx]

I would recomend the dunlop dc brick, its great boath 9 and 18 volt outputs

[MikeH]

They can't be in series- they wouldn't work then right?  For each plug, all of the positives are connected together and all of the grounds are connected together.  Thats parallel right?

I dunno man, I only see two wires coming out of my adapters, and unless there are some tiny tiny sheilded wires inside the outside wire

The wires running to each plug are shielded cable.

[Mark Hammer]

There are many different ways of isolating outputs.  For example, if you made yourself a little distribution box with a plastic chassis and, say, 5 jacks (1 in and 4 out), you could run the output of a single 3-pin regulator (the 1-amp variety, naturally) to four outputs, each having a diode in series with the regulator output and a 220uf cap to ground after the diode, that would not provide flawless isolation, but it would reduce the likelihood of line noise from one pedal affecting another (assuming each output goes to a different pedal).  Note that anything on the power line in pedal A would have to go through 2 diodes (which are back to back and end-to-end, I might add) and a pair of 220uf caps to have any audible impact on pedal B.  This is what I mean by pedal-to-pedal regulation.  I would not dream of calling it "isolated", because it isn't, but it moves in the direction of preventing the spread of line-noise across pedals, and that's one of your goals.

Note as well, that even if you had a fabulous $300 power supply that provided 6 exquisite isolated outputs, and you ran mini daisy-chain cables from each output to 3 pedals on your mammoth pedalboard, those 3 pedals aren't necessarily isolated from each other.  Just remember that true isolation assumes non-sharing of any aspect of power.  True, you are not "infecting" those 3 pedals with anything coming over from the other 15 pedals on your board, and it certainly isn't a waste of your time and effort, but anything less than one isolated output per pedal is not really isolation in the strict sense. 

[Bucksears]

I'm recently discussing this with my cousin who is running a Boss TU-2 Tuner with a daisy chain supplying power to a few DIY pedals. I had a Godlyke Powerall that I liked until it started frying the 100uF-cap-on-the-9V-rail on almost every DIY pedal I built.
I bit the bullet and bought a BBE SupaCharger and couldn't be happier (unless I had more outputs). Not one cap heating up or anything, no noise, no issues. An individual wall-wart is the next best thing, I guess, but even those aren't regulated as well as a power unit like the Supa.

[liddokun]

I''ve got a Godlyke and it gives me no problems.  I have about 14 pedals going off it, mind you I never have more than 2 on at a time. 

And as for what someone said above, the daisy chains are in parallel.  If you have a DMM with continuity checker on it, connect one probe to the first barrel, then one probe to the last barrel, you'll find they are connected. 

[cheezit]

..if you made yourself a little distribution box with a plastic chassis and, say, 5 jacks (1 in and 4 out), you could run the output of a single 3-pin regulator (the 1-amp variety, naturally) to four outputs, each having a diode in series with the regulator output and a 220uf cap to ground after the diode, that would not provide flawless isolation, but it would reduce the likelihood of line noise from one pedal affecting another (assuming each output goes to a different pedal).  Note that anything on the power line in pedal A would have to go through 2 diodes (which are back to back and end-to-end, I might add) and a pair of 220uf caps to have any audible impact on pedal B. 

Hmmm....well, don't most DIY pedal circuits have that diode + 100uf cap pair built in?  Certainly this could help for a circuit that doesn't, but would it really add anything to one that already has it (such as the BSIAB or a modernized FuzzFace)?

[brett]

Hi
every DIY pedal that I've ever made had an in-line 1N400X diode and a 470uF cap. 
Just good standard practice.
If you want to get really good low frequency protection (e.g. from flouro lights or a rough generator), you would add a 2200uF cap and a 4.7 ohm resistor for a decent 1 pole fiter (-12db at 60Hz).

Also, as Mark Hammer said: "Just remember that true isolation assumes non-sharing of any aspect of power."
That includes the earth.  We rarely talk about DC and low frequency "lifting" of the earth (except maybe for DI boxes where it can be a real pain).
cheers

[R.G.]

I ran into an interesting one while tracing the Boss PH-1R. The power supply for early Boss pedals includes a diode or resistor on the negative side. Put one of these into your pedalboard without thinking about it and you'll quite likely have some grounding problems. I'm not sure why they did it that way.