Tweet
The HM-2 is frequently modded by people by bypassing the crossover distortion diodes (D6 and D7). In my HM-2 clone (a Walrus Audio Red) I bypassed those diodes with a 75kohm resistor, to only decrease the crossover distortion. The problem with these mods is that the crossover distortion diodes also block noise.
I found that my pedal became unacceptably noisy after partially bypassing D6 and D7. The circuit is quite noisy. But, I was able to reduce the noise without affecting the tone of the pedal. I replaced R16, R19, and R21 with values scaled down by 1/10, and increased C6 by 10x. This significantly reduced the noise, though it is still noisier than many of my pedals at similar levels of gain.
I plan to do the same scaling with R29, R22, R26, and C11, but my “clone” is wired differently between the gain stages. In the Red the gain control is not wired like on the HM-2, and I haven’t yet been able to trace the circuit and locate the proper components for the mods.
Just sharing, in case anyone thought their HM-2 was too noisy. Thanks for reading.