HBE Hematoma mod question

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HBE Hematoma mod question

Silver Blues
Short version:

It is said that removing the 1M resistor from the MPSA18's base (in the overdrive half) to Vref will improve the sound. I removed it in my build, and indeed it did make it sound a hair more open... I just left it out. After looking at the schematic I don't really understand what that resistor is doing there in the first place. There's already a 1M to ground that biases the tranny, is there not? What's the other one for and why would removing it make it sound better?

Schem is here.

Thanks for any help. It's really not as bad a pedal as people tend to think it is.
Through all the worry and pain we move on
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Re: HBE Hematoma mod question

induction
That looks like pulldown resistor to prevent switch pops when switched on in unboosted mode. It will decrease the input impedance a little and make it less bright.
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Re: HBE Hematoma mod question

Silver Blues
I see. Strange... It seems to have the opposite effect for me. The pedal is quite dark stock. Anyway, it doesn't pop with or without it, I'm not sure whether to leave it in or take it out as the difference is extremely subtle.
Through all the worry and pain we move on
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Re: HBE Hematoma mod question

induction
If it doesn't bug you, I suggest you leave it in. It might not pop without it now, but a little insurance can be a good thing. If it starts popping later (in the middle of a gig, of course) you'll just end up adding it back in.
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Re: HBE Hematoma mod question

Silver Blues
True enough. Thank you
Through all the worry and pain we move on