Analog synth power help

Joshua VanderVeen

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Jan 8, 2014, 11:05:48 PM1/8/14

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A few years back, I dove into DIY analog synths, but never took classes and never really had a teacher or mentor to show me the right and wrong way to do things, or how to improvise and troubleshoot my problems. It seemed pretty straightforward at first, but these larger jobs are a bit over my head. I'd like to get back into it and finish these projects, but I think I need someone to hang out with and give me some pointers. I also no longer have the oscilloscope I used in the past, and a multimeter only gets you so far...

The one specific issue I'm having is with a power source on an analog filter synth. I built the "Sub Commander" guitar synthesizer from Music From Outer Space (link below), but I've never built something quite this intense. The design didn't have a footswitch for full-bypass, so I tried to fit one in, but I'm still not sure how to get the 12V power to the thing. The schematics simply point out incoming power, but no instruction on how to build it. I was intending on using a 2.1mm DC jack and plugging into a pedal power supply and distributor brick, but when posing this question on the forums at electro-music.com (where I've gotten help previously) I was told the schematics call for a dual supply. I seemed to miss that and have no idea what to do. The guy suggested I use AC power, but I don't know anything about that. It's been suggested that I build the MFOS Wall Wart, but I'm pretty intimidated by that. Anyone know what I'm talking about and might be willing to hang out and talk shop? I'd really appreciate it.

http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&PROJARG=GUITARSYNTHAUG2007/GUITARSYNTHAUG2007.html&VPW=1430&VPH=708

Timothy Bieniosek

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Jan 9, 2014, 8:46:03 AM1/9/14

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Hi Joshua,

EuroRack modular synths use +/-12V power supplies, so you could look there.

PAiA sells a kit which is a little less nuts than the MFOS "good luck you're on your own" plans...

http://www.paia.com/proddetail.asp?prod=9770R-12&cat=12

Oh! I just remembered, PC ATX PSUs supply the voltages you need. Find an old one and hack up the connector, or Sparkfun sells this breakout...

https://www.sparkfun.com/products/9558

Tonight is project night at the Hacktory. I plan to be there and I'd love to talk shop.

Tim

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Natalie Hirneisen

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Jan 9, 2014, 9:05:24 AM1/9/14

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simplest and cheapest is just to use 2 off the shelf wall warts, just wire the one back wards to get the negative 12V . I'd add a power switch after the 2 warts to make sure both power rails come up at the same time, since some op-amps don't like being one sided. the advantage of the wall warts is you don't have to wire AC mains voltages.

Otherwise Acopian (a local company that makes good products) has a dual supply

http://www.acopian.com/store/productdetail.aspx?q=dNominal+Output+Voltage+%2B%2F-:+12;+Current+Amps+per+Output:+0.1;+++Regulation+Load+%2B%2F-:+0.05;+Regulation+Line+%2B%2F-:+0.05;++Ripple+RMS:+1;+Case+Size:+EL-10,i1805

you will need to build a electrical safe box for it such as a steel duplex box, make sure its grounded and fuse the hot input with about a 2A MDL fuse.