Dr. Boogey observations/questions

[m-theory]

Well, I must admit, as much as I thought I wouldn't be much into this circuit, after building one for my boss's son, I'm compelled to build one for myself as well.  It is a rather interesting circuit after all!

I have a couple of questions, however, based upon observations that I've made with it.  

1)  Why does the tone thin so drastically when the gain is dailed below about 75%?

2)  Is there anything that can be done to reduce or eliminate that thinning?  

Thanks, and kudos to the designer of this terrific, absurdly gainy circuit!  

[ayayay!]

One theory is the taper of the gain pot.  I prefer a 500k reverse taper on that.  You can also use a 1meg linear pot, with a 1 meg resistor across the outside lugs to simulate a 500k reverse pot.

The other thing is the gain is a balancing act that lies in the biasing of Q1 & Q2.  You need to shoot for the perfect balance of clarity & gain on both of those with the gain knob maxxed AND the gain knob at 50%.  Find a happy medium on those and you're about 85% there. 

[m-theory]

How is it that turning down the gain with the stock A1M would make the circuit sound trebely/bright but doing the same thing w/a C500K wouldn't?  I don't follow that. 

[ayayay!]

...would make the circuit sound trebely/bright...

I didn't know that's what you meant when you said "the tone thins so drastically."   

[m-theory]

I mean that the tone thins drastically when the gain is turned down below about 75%.  At max gain, it's fat and huge.  Turn it down to 75% or lower, and ice pick treble overwhelms. 

[dschwartz]

the cap between lugs 1&2 on the gain control regulates the amount of treble bleed to the next stage when the gain is lowered.

Remove it or make it bigger for a fuller sound on lower gains..

i like it the way it is, twangy and sparkly at low gain settings...
consider putting a 10n cap to ground just before the output volume pot (between lugs 1&3)..100% improvement if too much treble is your issue

[m-theory]

Twangy and sparkly is fine on some circuits, but it's not really how I'd describe a dual rectifier!  Granted, the gain will most likely be dimed at all times on this (it's going to be in the hands of a 15 y/o kid), but still, I don't want the circuit to completely change character when the gian is turned down, and that's what it does now.  I goes from being a forboding, massive wall of thick, distorted sound to this spanky, bright, twangy, Nashville-esque tone that just completely flies out of character, imo. 

the cap between lugs 1&2 on the gain control regulates the amount of treble bleed to the next stage when the gain is lowered.

Remove it or make it bigger for a fuller sound on lower gains..

Duh...I completely forgot about that cap!  Thanks!

consider putting a 10n cap to ground just before the output volume pot (between lugs 1&3)..100% improvement if too much treble is your issue

I'll try this as well.  It does seem to have an vast abundance of high end overall...I generally run the treble no higher than 10:00 or so, and even that seems a bit much to me.  Thanks again!