3 knob treble booster

[Gus]

A three knob treble booster.  A set of values I like.

R12 Tone 250K
R3 Bias 2.2k to 7.5k, fixed 2.2K in series with a 5K potentiometer wired as a variable resistor
R1,R2 one Volume 10kA
Try a 2N3904
Circuit is to the right of the X at input. The stuff to the left is a simple guitar cable sim
Add power protection
Ignore bias by the volume control that is from another sim. I forgot to remove it from the screenshot



Have fun

[Kipper4]

Thanks Gus.
Another for the breadboard.
Curious about the variable capacitor to see how effective it will be in the real .

[Gus]

The tone is based on the cap blend Joe G. posted years ago.  I simmed different value caps and resistances until I found what looked like it might sound good for  treble boost. The screenshot has a simple single humbucker guitar sim volume at max, tone at max, 370pf of cable capacitance.

You could also use the switched cap input if you want greater tone changes.

[Kipper4]

Thanks Gus the tone could be a deal breaker if it came to sales.
Switched tone seems like a good alternative.
Cheers
Rich

[anotherjim]

I built an RM not long ago to use up an old Ge NPN (AC127 IIRC). Mine got 3 knobs too!
I used the same input cap tone control as above (can't remember values). It works well for me. Not as repeatable as a switch cap scheme, but no need for extra anti-pop resistors either. If the pot is large enough R and there's sufficient difference between the caps, the control goes all the way from all-boost to original top-boost.

My 3rd control is varying the bias feed (R5 above) instead of the emitter resistor. Since the RM is affected by input impedance interaction, I was interested to see if being able to tune the front end was worthwhile. It seems to be, there's an obvious sweetspot on my build which moves according to guitar type.

[Derringer]

Nice Gus

here's something I did a few months back with a pair of low gain germaniums.

Ended up making R4 into a variable 5K resistor/pot to adjust bias/gain as I was having some gating issues in the build.

[Cozybuilder]

I just got through breading your 3-knob TB with a 2N3904, and it goes from sizzling treble to about normal, but with a huge volume cut. I changed the 250K pot for a 100K linear, and really like the tone control now, not a lot of volume drop. The bias adjustment gives from 1.2V to 1.3V on the emitter and from 3.9V to 6.8V on the collector. Theres lots of volume on tap. I like it!

[Gus]

Cozybuilder
Thanks for the feedback I did not build that tone control. however I often use switched cap at the input of fuzzes etc.