Problem with Chasm Reverb Build

[samhay]

Jumping the FETs tells you what it should sound like if the FETs are working.
If you get the same result when you hit the switch, then they are fine.

You mentioned you are using the BTDR-3. Turn down the dwell time -  the dual 10k pot connected to the extra pins. There should still be some slap-back like pre-delay with this at minimum.

Overdriving could also suggest you are hitting it with too hot a signal. What are you feed it with and can you turn it down?

[undercurrent77]

Samhay,
  I apologize it's taken me so long to reply.  Unfortunately daily life kind of got in the way of working on this the past week.  I had a chance to test a few more things so here's what I found.  If I plug in the audio from my cell phone set to a reasonable listening level everything seems to be working fine.  All the controls and bypass switch work just as they should.  However, that's not the case when I plug my guitar into the circuit and play through there.  I'm using a seymour duncan humbucker into a vox ac15 set nice and clean.  No crazy high gain active pickups or anything and the guitar itself is turned just down from max.  Bypass works great and if I turn the mix knob all the way down while effect is engaged, at unity volume is where I notice a slight bit of distortion creeping into the signal but it's really only noticeable on the natural trail of the note.  Once I add the reverb into the mix is where things get a little whacky.  Turning the dwell knob (the dual gang pot from the btdr-3) all the way down as you suggested drops the length of the reverb just as I would expect. 
   With any kind of reverb mixed into the signal, the distorted starts to kick in.  I turned my guitar volume way down and it seemed to get rid of the distortion, but the signal was so quiet at that point I could barely hear anything at all.  Is there anything in the circuit that could be acting as a boost and pushing my amp to overdrive?  Also, this is where the delay between my picking and the actual sound comes in.  It doesn't seem to be effected by turning the dwell knob even though I can definitely hear the length of the reverb being adjusted.  It's pretty significant...probably around half a second from when I hit a note to when it actually sounds.

[samhay]

3 of the 4 op-amps can provide boost, so if you have wrong resistor value(s) somewhere, you could be boosting your signal, which is then distorting.

The first 2 resistors I would check are R6 and R7 (using the numbering form the schematic here:
http://www.coda-effects.com/2016/02/dead-astronaut-fx-chasm-reverb.html )
R6 should be easy to find as it is connected to the MOSFET you have been playing with earlier. R7 will be connected to the other end of this.
Sorry, I can't see the layout anymore as it looks like Rob was hosting it from a Dropbox public folder (Dropbox just dropped this feature).

As far as the delay goes, the BTDR bricks do have some inherent delay. The dwell control on the -3 version varies this quite usefully. I would not include the Decay control in your build as this was a hack designed to add dwell to the older BTDR bricks, which don't have this feature. It is mostly redundant and it doesn't work as well as the proper dwell control anyway.