welcome to Apocalypse Audio, your haven for DIY guitar effects in the end times. so, start prayin to the fuzz gods, savin up those parts, and remember, when the big one goes off- keep your transistors shielded from those pesky electromagnetic pulses!



a while back the stompbox god RG Keen posted a schematic of the Roland AD50. but alas, it looks as if even the gods have their weaknesses, because i noticed that the schematic was missing a master volume pot for the fuzz. then Analog Guru over freestompboxes.org enlightened me to a few missing parts and pot values.

so now, i present to you, finally unchained, the correct Roland AD50 Double Beat schematic.


  1. Good job looking into that schematic before actually buying the stuff needed. A lot of DIY folks out there just download schematics like crazy without even reviewing it. I'd love to download this one, but a AD50 would be too technical for me to even tinker with.

  2. thanks Miriam! it is true that there are errors in many schematics on the net. people like analogguru have really been a great help in this regard. at FSB, we like to double check everything with gutshots before calling it verified.

  3. btw-there is a vero layout for just the fuzz section here on the blog. it really sounds great, and you could cut out the switching for the output cap easily, which would simplify the build a bit. just take it slow, and go for it! you can always let me know if you have any problems.

  4. With regard to the fuzz section: anyone have any ideas what hFE's are recommended for Q1/2/3, and any pointers for biasing this thing up for best tone? I have a supply of Toshiba 2SC1815-GR's that I've used to build a couple vero copies with 1% metal film resistors, but they aren't particularly consistent, which is strange for a highly filtered silicon fuzz. Should Q1 and 2 be biased/treated like a Si Fuzz Face in terms of transistor gain selection?