A fast-n-ugly solution for my ROG Condor Sim issues

Started by phaeton, October 13, 2014, 09:48:43 PM

Previous topic - Next topic

phaeton

After a long hiatus from tinkering (pushing a decade, unfortunately) I started back into some projects.  A few weeks ago I did the Runoffgroove Condor Cab Sim, as I have this grand vision of a modular 'practice board' where I can play along with a CD or MP3 player into headphones with great sound.  The Condor is the first piece, and it was pretty straightforward, even though I added a power on/off toggle switch:

http://i.imgur.com/d0IiBOO.jpg

I was having issues with the gain pot having minimal effect, and getting a constant gravely distortion, even with my weakest guitar (SSS Affinity Strat).  I checked and re-checked my voltages, retraced the circuit, tried different JFET and OpAmps (hooray for sockets!) and even got drunk and yelled at it.  I came here to do some searches, and it turns out that a handful of folks were having a similar set of issues (and yet others weren't having them at all).  Some folks from ROG offered some solutions that involved reworking the input, but I wasn't really feeling up for reconstructive surgery right now.

I eventually ended up pulling the J201 out, and sticking a 0.1uF cap into the socket, with the leads in Drain and Gate.  It takes a huge gain hit (expected) and also bypasses the gain control, but it solved the distortion problem.  The circuit sounds pretty good!  It is way below unity now, so I can't use my extra bypass toggle I added to it, but I'm ok with that. 

I know it's not the best solution, but I thought I'd share in case others had one of these laying around that they never solved the distortion issue on.  It's a pretty good circuit, though I think they mean it when they say "This project is rated 2 out of 3 for complexity".
Stark Raving Mad Scientist

alfafalfa

Have you tried leaving the J201 in and change the 1K pot for a higher value e.g. 2.5 K. Or you could try to put a 1 K resistor between this pot and ground.