If you're going to build your own audio gear, you probably have to put it in a case, right? Enclosure? Rack?
Indeed, that's where the choices start.
My DiWhy friends work with Euro mostly for their modular synthesizer projects, some MOTM, and a few the social media savvy "kosmo" format.
My geek audio buddies still aren't sure why I build almost exclusively in Paia Frac, but I'm sticking to it.
It's a pretty uncommon format, but this week as I was blowing up power supplies I was glad I use to it rather than some of the more popular choices.
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| +/- 15V Frac power with temp front panel.... |
I was doing some recording when all of a sudden from my noise generator came a nasty 60 cycle hum. Not all my modules did this, just a few, and I quickly traced it to one of my original (circa 2003) Frac power supplies. that powered the noise modules as well as a few balanced modulators.
I have already posted building a custom 15-15V linear supply (post is here).
I hate 60 cycle hum, and it's more fun to build something new than fix broken, so let's build another.
Frac power is modular, like everything else about it, and modular engineering is good engineeering.
A new linear supply for Frac is easy--especially when you have brand new boards provided by my generous sponsor PCBWAY--and uses mostly junk box parts:
I plugged in the new supply to test--second time in a day!!--SMOKE!
This blew up a surplus16VAC 40VA wall wart as well as both of the regulators.
Hello?
The diodes used to safeguard the regs from reverse voltage looked like chunky diodes in my junk box, but turns out they were precision low value high watt resistors.
Ooops. that's what you get when using junk box components and a lack of caution and patience.
Not a big deal to replace impacted parts and put in diodes where they are needed; now it works.
The good news: when you have a power supply problem with Frac, it doesn't take out your whole rig, and conversely, if you have a bad module (DiWhy--that will never happen right?) it won't take out your rig's only power supply.
Frac is also a reasonable size, not too tiny, but not like MOTM or Moog or synthesizer.com formats where it takes up your entire living room; Frac is affordable, fits in a 3u 19" rack case, and maybe best of all, PAIA is a cool small mom and pop type company, left over from the phone-phreak/Radioshack electronics geek 70's. There aren't too many of those any longer.
Note that PAIA supply I laid out and built (this clone is based on some of PAIA's earlier 9700 series designs, but beefier in terms of sourcing and sinking more current) use a ton of .1uF caps close the the .1mil DC headers. I discussed these inclusions with some pro EE's--I am not one--and was told that all these .1uF caps makes no different close to the headers and can be omitted--these filter caps need to go on the modules that are being powered, not here.
So for now, you can leave 'em off. I have left them off my recent builds and can't hear any difference with ripple, buzz, or other unwanted distortion.
You can download the gerber and BOM for the power supply I use here from PCBway's project page, here.
Please help support this geeky blog by checking PCBWAY out and consider using them for any fab work you dream up.
If you come up with any sort of mod or change to the power supply comment below, I am curious what you folks, my trusted readers, come up with.
See ya next time.
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