p_wats
Well-known member
It's no secret I've had a bit of a rough spell with regards to troubleshooting FV-1 builds that worked fine until I did something dumb.
Hopefully I'm over the hump now though, as this one is a doozy. I built this double Arachnid last year for my wife/bandmate to use with her synth setup. She loves it and has very specific settings she likes to use, so it was a bummer when one of the rotary switches died.
I was able to get it desoldered without issue and popped a new one in, but there was now a lot of noise--after much troubleshooting (thanks again to @zgrav) I was able to figure out that jostling the circuit to get the board out/in of the box must have pulled too much on the board-mounted pots, as a trace came loose at the mix pot. A quick extra jumper wire later and problem solved!
Then, it was time to see if I could push it further without actually breaking anything this time. The new additions are:
- Toggle to engage internal programs for the second circuit (didn't feel the need to do this for both)
- Dry out from the 2nd circuit via pin 7 of the TL074 (via a 1uf MLCC and 1K resistor to the ring of the stereo jack) with a little breakout cable to send the tip (wet) and ring (dry) to different ends
- Daughter boards to toggle between 2 EEPROMs for each circuit (as per this thread. Thanks to @phi1 for all his documentation there!). This could be done more elegantly using pin headers, but that wouldn't work with the IC sockets I had used, so this needed wire leads soldered to socket ends.
The other options already included were a toggle to switch the order of the two circuits and an effects loop to insert something between them.
The labelling got a bit messy as I added more and more options, but these new ones are mostly for me for when I "borrow" it from her to use with weird programs, etc.
Hopefully I'm over the hump now though, as this one is a doozy. I built this double Arachnid last year for my wife/bandmate to use with her synth setup. She loves it and has very specific settings she likes to use, so it was a bummer when one of the rotary switches died.
I was able to get it desoldered without issue and popped a new one in, but there was now a lot of noise--after much troubleshooting (thanks again to @zgrav) I was able to figure out that jostling the circuit to get the board out/in of the box must have pulled too much on the board-mounted pots, as a trace came loose at the mix pot. A quick extra jumper wire later and problem solved!
Then, it was time to see if I could push it further without actually breaking anything this time. The new additions are:
- Toggle to engage internal programs for the second circuit (didn't feel the need to do this for both)
- Dry out from the 2nd circuit via pin 7 of the TL074 (via a 1uf MLCC and 1K resistor to the ring of the stereo jack) with a little breakout cable to send the tip (wet) and ring (dry) to different ends
- Daughter boards to toggle between 2 EEPROMs for each circuit (as per this thread. Thanks to @phi1 for all his documentation there!). This could be done more elegantly using pin headers, but that wouldn't work with the IC sockets I had used, so this needed wire leads soldered to socket ends.
The other options already included were a toggle to switch the order of the two circuits and an effects loop to insert something between them.
The labelling got a bit messy as I added more and more options, but these new ones are mostly for me for when I "borrow" it from her to use with weird programs, etc.
