Power Supplies for bench testing/poly shruthi use

I was wondering what people here, including Olivier, use for bench supplies. Stupidly I hadn’t even thought about using an ATX PC power supply til this evening. Now that I consider it, I should be able to wire up connectors for several Shruthis, my Anushri, MIDIBud (MidiPal variant, thanks kvitekp), and a few other things including my MPK-61, and a few pedals. Any thoughts on this? Sure the atx would be big, but I reckon I could wire up a nice harness and have a shelf dedicated to this on my portable setup:

It’s clever and you should have enough amperage for a lot of synths. But be careful with the 12v power supply, it will push the +5v regulators in certain editions of the shruthi (I’m thinking about the lp2+dly mostly, but the 4PM is a sucker as well, and the anushri is quite surprisingly demanding as well).
If you have some air flux in the room it will be ok. If not, you can use some radiatored 7809s or 7808 so they can share the load with the shruthi regulators (an even better option to consider is to grab some lm2675s).

Be aware that some ATX Power Displays tend to die if theres no load…

Those are very, very ancient then. But yes this used to happen.

I might invest in a proper bench-supply later. At the moment I use an array of cheapo wallwarts - if it works for me, it will work for you :smiley:

PC supplies will be cheaper and more available, but they have fans and you don’t really need the complexity of them.

Get a power supply module, you just need to stick them in a box and attach via some crimp connectors. Something like this looks suitable for the Shruthis (7.5v):


The main reason I’m considering this is: I have a few sitting around. I’d likely use the 5v supply for the shrug his if its strong enough however I could make a circuit to bring voltages down to 7.5 or or so pretty simply. The number of available supplies seems the best part.

I am currently using my supply of variety wall warts. Is funny how many people look at you funny when you reclaim these things from trash bins around an office or whatever. Little do they know. Recently I saw a printer lying on the sidewalk waiting for the garbage collectors. It had a nice solidly constructed USB b cord in perfect condition, score. So yeah, I’ll dive if it saves bucks for the hardware I won’t just find lying around.

You should have considered dismembering the printer in search for a workbench power supply. Especially laser printers are loaded with really good power supply cards with a nice variety of voltages (it’s not rare to see 15 or 24v DC), little fans, etc. I’ve got a 12v power supply in an aluminum enclosure that looks pretty much like what 6581punk linked above. For free, of course.

Under the impulsion of my belarus colleague who’s an expert at recycling electronic stuff (like, he repaired a trashed lcd screen with a step-driver chip borrowed from a trashed printer…), I always spend some time to go to the electronic trash of my working place. I currently work in an engineering school with a nice load of research labs, and there’s always something cool to find. People are throwing away functioning scopes. Last time I even found a 27-bands graphic equalizer (?). So, next time : dismantle that printer, you may grab a workbench power supply…