To increase volume, I slowly increased the vol pot. Even at 1M, it was still below unity. So, I added diodes in parallel. Finally it was above unity, but now the distortion (really a tone control...closer to 0K the more bassy) didn't give me a good sweep. So, I simply increased the 27K cutoff to 100K and subbed a 1M distortion pot instead of the 250K. Beautiful! That gave me a nice sweep from just barely too bassy to a nice thin fuzz.
Mild Gating Problem:
Anytime I see an odd small value from an emitter, base or collector to a rail, I always suspect it to be very sensitive, and it was...I slowly increased from 0K and hit a perfect spot around 2.6-2.8K. The mild gating and pick percussion were gone, resulting in a killer smooth fuzz with super long sustain. It was nearly perfect, but a bit too harsh on the highs. A simple tweaking of the 680 gave me a sweet spot right around 1.8-2.2K. If you raise it much higher, you'll wind up with less power...and around 4-5K will start to gate again. Further, I increased the 2M to 3M, which gave a bit more richness to the higher strings. I tried up to 7M...still good (thicker on the high strings) but I didn't want to take a chance it would change the tone too much.
Here's a demo of the original:
If you want use this layout to build the SquareWave to original specs, follow the below value changes:
- Change the 1.9k resistor to 680Ω
- Change the 2.8k resistor to 3.9k
- Change the 3M resistor to 2M
- Use a 2N5458 for Q2
- Jumper D3 and D4
- Change the 100k resistor by the diodes to 27k
- Use B250k pot for Distortion control
- Use A50k pot for Balance control