ctelecaster
Member
Hi there,
Having some issues with my Blue Breaker build. Technically my second one - I built one as a trial run to get my soldering technique down. I put it all together and I got sound in bypass, and power/LED when on but weak signal. I get about unity gain with the volume and gain controls both fully up, and the signal is being colored somewhat by the circuit compared to bypass. No crunch or distortion to be heard. The tone control behaved as expected. It almost seemed to a layman like the signal wasn’t being amplified, just passed through the circuit.
I decided to start from scratch on a second PCB with all fresh components since my soldering on the first go was less than stellar, and it behaves exactly the same as the first. I’m assuming there’s some kind of common issue with both boards I built because they both behaved exactly the same, but I am at a bit of a loss as to what it could be.
Things I’ve tried:
Having some issues with my Blue Breaker build. Technically my second one - I built one as a trial run to get my soldering technique down. I put it all together and I got sound in bypass, and power/LED when on but weak signal. I get about unity gain with the volume and gain controls both fully up, and the signal is being colored somewhat by the circuit compared to bypass. No crunch or distortion to be heard. The tone control behaved as expected. It almost seemed to a layman like the signal wasn’t being amplified, just passed through the circuit.
I decided to start from scratch on a second PCB with all fresh components since my soldering on the first go was less than stellar, and it behaves exactly the same as the first. I’m assuming there’s some kind of common issue with both boards I built because they both behaved exactly the same, but I am at a bit of a loss as to what it could be.
Things I’ve tried:
- Measured every resistor for correct value and every diode for shorts one by one when populating board - everything checked out.
- Since it sounded to me like the signal was being passed through without amplification, I suspected the op amp. I tried several different TL072s with no change. Thinking I may have gotten a dodgy batch of TL072s from Amazon, I swapped in both a 4480 and a 1458 both sourced from stompboxparts, also with no change.
- Noticing a discrepancy between the printing on the board and the values in the build guide, I swapped the positions of adjacent 1K and 1M resistors (R8 and R10). The printing on the board appears to be correct as the traces are correct relative to the resistors, but I figured I would give it a shot. No sound at all after swapping to match the build guide, weak signal came back after swapping back to match the board printing.
- Reflowed everything twice in between tests.
