Last post of 2014. Happy New Year, everybody!
Here's the early 80s DOD FX55 Distortion, without the original switching circuit so you can wire it for true bypass. The original used a TL062 dual op-amp, but the 2nd half of it wasn't in the signal path all, so I went with the single TL061. The off-board wiring pads aren't as neat as I'd like, but I wanted it to fit in a 1590a.
You could fairly easily use this same layout to make the DOD FX50 overdrive with the following mods:
• Change the 1k resistor to 4.7k
• Change the 3.9M resistor to 1M
• Place a 1n capacitor between lugs 1 and 3 on the Level pot