isolated pedalboard power supply with multiple voltages?

Started by spectraljulian, February 12, 2008, 12:53:02 PM

Previous topic - Next topic

spectraljulian

Hi, I'm doing some research into a possible project. 

I currently use 4 wallwarts for my board.  A 1 spot powering 5 pedals, a 9.6v 200 amp for my EHX SMMH, a 24 v adapteer powering my phaser, and a 40 v adapter powering my ring mod. 

It is kind of clunky, and rather messy.  The 1spot is quiet until I add a 5th pedal, at which point it introduces a high pitched squeel when my Korg DT-10 is off

I've been tossing around the idea of building a power supply for it all.  But I can't find any info other than the page about the Spyder on geofex. 

Yes I know the Voodoo labs PP2+ can do all that except 40v (which can be handled by using the courtesy outlet) but I'd like to have something I built that I can expand for future needs, which I think will exceed what the PP2+ has to offer. 

Can someone point me in the right direction? 

R.G.

R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

spectraljulian

I've seen the spyder.

But what about making a power supply for 40v? 12 v?  24v? 18v? 12 ac? 9 ac? 9 v dc high amperage

MarcoMike

#3
it looks similar to my pedalboard...I have a 9V spot for the first half, distortions, wah, comp,....then there is a 9.6V spot for all the digital stuff the digital stuff (reverb, delay) and my tremolo. I recently added a 12V spot which powers my THOR. and there is a 220Vac line for my Morley PFA. everything gets powered just inserting one plug. (how difficoult was my life before.... :P)
all DCs are regulated using 78XXs from a rectified 12,some V ac transformer mounted on the pedalboard in the digital side.
it's really silent! much more than expected, I can hear noise only when the Big Muff is on...

anyway, your voltage demand is more complex, I would go this way:

33V ac -> bridge rect, caps -> 45V dc -> lm350 (or similar) -> 40Vdc -> LM7824 -> 24V dc  ------> LM7809 -> 9Vdc for some pedals
                                                                                                |                                  |            |                        
                                                                                             ringM                           phaser        ---> LM7809 (diode trick) -> 9.5V dc  EH

if the 40V you need in the ring mod are not required to be regulated and it doen't have do be an exact value you can make it even simpler...

(I hope the schem is clear, I had to edit it because it came out different than when I wrote it)
Only those who attempt the absurd will achieve the impossible.


Minion

I would get a center Tapped 30v,0v,30v Transformer, and use a LM317 regulator to regulate the 44v DC to 40v Dc and then Put another regulator on the 40v output and regulate that down to 24v and then put another regulator on the Output of the 24v regulator and regulate that down to 9v and then you will have your 9v ,24v and 40v supplies, You will probably need a heatsink on at least the 24v Reg and the 9v reg and maybe even the 40v reg depending on the current draw....

This is actually a pretty easy project, I have built several simular PSU"s in the Past....
Go to bed with itchy Bum , wake up with stinky finger !!

spectraljulian

I don't know too much about regulators or power supplies in general, would chaining it with regulators like that make it unisolated?  I'd prefer to not to worry about positive/negative ground or one pedal causing noise. 

MarcoMike

Only those who attempt the absurd will achieve the impossible.


jakenold

I would get a couple of transformers to do the job.

Find seperate transformers for all the different voltages, and choose either units with the appropriate amount of windings, or multiple units of the same type. I've done something like it, with the "Spyder-transformer" - I chained some of the outputs to get 24V for my EHX-equipment, and used the 1:1 that Mouser and Smallbear sell to isolate them for more outputs. Works great!

Jake

Minion

Regualtors are pretty easy to work with as most are just 3 legged devices, The Datasheets on the regulators show examples on how to use them.... The Power supply will still be Isolated (the power transformer isolates the Voltage from your House Voltage) ...There are many Advantages to useing a Regulated power supply ,Like Lower Noise, There are no voltage sags as current demand Increases and with the Right Filtering you should notice a much less noisy Pedal board.....

Common Regulators are the LM317/337 adjustable regulators which are extremely low noise and there are the Generic LM78/79 series of regulators that are very cheap and easy to get but they aren"t as low noise as the LM317/337 regulators.....Doing it this way is probably cheaper and more reliable and with much less noise than buying a Transformer with multiple secondaries because with a Transformer with multiple secondaries you will have to use a different rectifier for every output Voltage and a filter Bank for every output Voltage, when useing regulators the way i suggested you just need one Rectifier and a Cap for every Regulator.....

If you need help designing a Regulated multiple output Voltage power supply let me know and I"ll help you with it....


Cheers
Go to bed with itchy Bum , wake up with stinky finger !!

Ben N

This may help:
https://taweber.powweb.com/store/pdlxfmr.gif
and
https://taweber.powweb.com/store/wpdlxfmr2sch.jpg

These guys give you multiple fully isolated taps for the cost of a couple of wallwarts. Of course, you still have to rectify/filter/regulate, but that is fairly simple to do and there is a lot to work with. Presumably you can combine windings and regulate to get your higher voltages.
  • SUPPORTER

spectraljulian

Thanks guys.  I think this will be my next DIY project.  I think I'll design it to be part of my next board.  I need a new one pretty soon.

Ben N

You still need to be aware of noise issues. Transformers generate magnetic fields that translate to hum that can be picked up by other thinigs with coils in them, like octavers and wahs. This is one advantage of wallwarts--they keep the noise source some distance from the pedals. When you move transformers to the pedalboard you have to be extra careful with placement--like putting the trransformer under the board and angling it so that it is at 45 deg to the coils that might pick up hum, as seen in some amps-- and shielding. And of course once you have shielded effectively, you also have to be concerned about ventilation/cooling.
  • SUPPORTER

spectraljulian

True true, although I don't think I have any pedals with coils in them. 

I'll put mine in an enclosure of some kind, with some ventilated holes.

My current pedalboard is angled, and my wall warts are all on a messy little surge protector underneath. 

When I build my next pedalboard and the accompanying power supply, I'm going for slightly angled first row, then a steeper angled tier. 

I'm going to buy some of these: http://www.onlinemetals.com/merchant.cfm?pid=1143&step=4&showunits=inches&id=997&top_cat=60, and put them on a wooden frame work, and spread them out so I can run cables underneath.   

The whole thing will have a base of some sort underneath. I don't like pedalboards that I intend to route cables underneath without a base, I think that is kind of sloppy.