Smoothed Switching or Linear Powersupply in guitar application

I'm wondering people's opinion. 

I have a bunch of a little 9v guitar pedals to power.  Currently, I'm using 2 linear powersupplies (these http://www.voodoolab.com/pedalpower_2.htm).  Each of these power supplies has a toroidal transformer with 8 taps from the secondary.  Each tap is then filtered and regulated (LM317s actually). Some of the outputs are switchable voltages as well (12v or 18v) - which can be handy. 

I'm wondering how that would fair in comparison to a switching powersupply that I load up with low esr filtering caps (kinda like JLMaudio's idea with their switching power supply).  Joe has a clean 48v supply that he runs through a transistor regulator with caps for a 24v rail (usually) and the existing 48v for powering Neve like preamps.

The plus side with the switching power supply is that it would take up a lot less room on this pedal board.  Plus it can run 240 or 120v.  I figure a little box with some 1000uf low esr caps may clean up any mess?  Something like this http://www.godlyke.com/Online_Store.php?thiscat=16&=SID

My current power supplies have separate taps but because the pedals are all unbalanced the grounds (through the sleeves) end up being all connected anyway (I guess with less potential ground contamination from each pedal though).

I'd really appreciate any insight/thoughts.

Thanks.

Chris

My former pedal board was an SKB PS25, which relies on an external PSU. Since I had two Line 6 pedals (not the big things that require 12V ac, but an Echo Park and a Roto Machine), I needed a lot of current. I made a number of experiments and I found that both Line6 boxes couldn't coexist if they had a common PSU, lots of digital clock interference. I'm not sure, but I guess a genuine multi-output unit may not have had the same problem. So I replaced the Echo Park with a Boss DD20. Linear PSU's (in fact I had one as spare, never had to use it) were too bulky so I tried about half a dozen switching PSU's, and only ONE worked satisfactorily, a Uniross adjustable-voltage thing rated at 9.6VA. All the others produced unacceptable noises and whistings. And I must say it has never been really super-clean, just moving the jacks in their sockets produced scratching noises (RF residues?).
Another problem was the fragility of the connection; I had to replace the plug twice.
Now I have a new pedal board, which I have equipped with a multi-output PSU (not dissimilar to yours), and at last, it is sooo clean...
and i'm not concerned anymore about a wild boar snatching the plug with his size 17 Doc Maertens.

Hmmm.  Thanks for your input there.  Seems one vote to keep things as is.

Have you ever placed a pedal on top of your power supply (the multi output one)?  Actually lots of power supplies have multiple outputs but not necessarily multiple taps from the transformer.  I assume yours are isolated taps.  My real concern is just running out of space!

CC

Nothing wrong with switchers.  Use a lot of ferrites and RC filtering to keep crosstalk down between pedals.

conleycd said:

Hmmm.  Thanks for your input there.  Seems one vote to keep things as is.

Have you ever placed a pedal on top of your power supply (the multi output one)? 

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Since the PSU is inside the new PB, one pedal is located right above it. That's the EQ pedal for the acoustic guitar. No interference.

Actually lots of power supplies have multiple outputs but not necessarily multiple taps from the transformer.  I assume yours are isolated taps. 

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Yes it is.

My real concern is just running out of space!

CC

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I sure understand that, but the improvement in performance is so dramatic I don't regret one second the bigger size!

Svart said:

Nothing wrong with switchers. 

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That's the theory. But some of those wall warts are so poorly designed it makes you wonder. And switching PSU's require so much shielding/decoupling/filtering it makes them incompatible with dense packaging and uncontrolled environment (and god knows how uncontrolled guitar pedals are).

Use a lot of ferrites and RC filtering to keep crosstalk down between pedals.

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Yes, that's what I would do if I was in my electronics designer guise
When I play guitar, I wear my guitar player hat, turn the brains off and just want to use the stuff.
On the old PB, I had installed a DC-DC converter to power the wireless receiver (different voltage and polarity) and tried to improve the digital noise/interference/uncleanliness with caps and inductances, but it didn't really work. Spent hours trying to get the "not-worst" of it.
With the new PSU, I just plugged the thing and it works.
In retrospect, the only reason I had investigated switching PSU's was because linear PSU's don't fit in a single plug on a distro strip. I reckon a good solution would be a clean switching PSU with a mains cord, not a wall-wart.

I use a switching power supply that is driving several 9v linear regulators which power the pedals. It works well and the 9v regs remove the noise the power supply.

Grounding may become an issue when driving numerous guitar pedals off one power supply but that can sometimes occur with any type of power supply....  which is why you see pedal power units that have multiple windings on the transformer so that problem pedals can be isolated.  I've not had that problem but it is definitely a consideration.

regards, Jack

I'm wondering is there any advantage to running small resistor in series with the power supply secondaries?  Does this increase smoothing or isolation?  Or is there only advantage in RC filtering.

Each of the secondaries on my power supplies are RC filtered and individually regulated.

CC