How to approach getting more treble out of a overdrive pedal?

[carboncomp]

Would someone be able to suggest components to play with to get a bit more treble out of this build?

http://beavisaudio.com/schematics/Images/ColorSound-Overdrive-Schematic.png

[GibsonGM]

Offhand, the 2 10n caps in the tone stack could be made something lower, say 5n, to shift the treble part of the tone control up in frequency.

I wonder if lowering C5 would trim so low end also...

[antonis]

I'd start by decreasing coupling ( C2 & C5) and decoupling (C3, C6 & C12) caps values..

Of course, what Sir Mike said is the correct approach but you have to play with Baxandall calculator: https://www.petervis.com/record_players_and_turntables/baxandall/baxandall-calculator.html

P.S.
Don't expect exactly what comes out of the above calculator 'cause Q3 Collector can barely be considered virtual ground..

[anotherjim]

The usual is not actually boosting treble but making it less bassy and that gives the overall impression of more treble.

The simple goto for most fuzz distortion is a smaller input cap C2.

Any of the bypass caps C3, C6 & C12 can be smaller. . C12 would be my choice to start with but it needs to go down to 2.2uF before it takes much bass away. 25uF is oversized in the first place. With a 470R emitter resistor, 4.7uF gives full guitar bass but with cap tolerances what they are and consecutive stages, designers deliberately pick oversized caps for the job.

There's nothing to stop you from changing any or all of the bypass cap values and not necessarily by the same amount.

[Mark Hammer]

The approach of dual (or even multiple) ground paths, illustrated in the Proco Rat, provides some ideas here.  One wants to retain the bass but get more bite.  So, as an illustration, one would keep C12 as is, but stick a small-value resistor (e.g., 120-180R) in series with it, AND place a smaller value cap (e.g., 470nf-1uf) in parallel with R14.  That would provide a basic gain for the whole spectrum, including bass, but MORE gain for that content higher up, as dictated by the direct path between Q3's emitter and ground.  The same strategy might also be applied to Q2 as well.  You will note that the amount of boost provided by Q1 relies on the resistance to ground from the emitter through that 10uf cap.

[amptramp]

You have a rolloff at 3128 Hz due to the series combination of C4 and R1+R4.  Reduce that if you want more treble but it is inside a feedback loop, so the effect may not be as much as it would be without feedback.

The higher you run your boost, the lower the input impedance is and this acts as a voltage divider with the inductance of the pickup and the input impedance.  This will reduce the high frequencies more as the boost goes up.  You could run a Darlington input with a larger R5 to raise the impedance.

[antonis]

I'm not sure if OP wants a Treble booster or a Bass hinder..

[Mark Hammer]

I suppose another approach, which does not change the overall bandwidth of the circuit, but merely what part of it gets emphasized, is to increase the value of C7, such that treble boost in the tone-control circuit, brings in more mids (with treble cut behaving largely the same as before).  So make C7 15 or even 22nf, and see what that does.

[blackieNYC]

I would avoid changing C2 - it will reduce bass on the input to the fuzz, and give you a lot less fuzz. The low frequencies do most of the work driving the distortion.  Filter them out later in the circuit if you wish for less lows. 

[Elektrojänis]

I'm not sure if OP wants a Treble booster or a Bass hinder..

Then again... most so called treble boosters are actually more like cutting bass and then just boosting everything. They are high pass filters with gain.

One thing I'd try is put a smalish cap in parallel with R2. Maybe 0.033µF for start and try some lower and higher values. I think it should give you some more treble on lower boost and pretty much stock responce on full boost.