katana boost (pedal pcb cleaver)

[baloubass]

Hello, i'm looking to a solution to reduce the overall gain of this build. it's sound really great but the ouput gain are too big for me. What i have to change to do this thing please?
thanks.

schematic:
https://www.pedalpcb.com/docs/Cleaver.pdf

[GGBB]

Try raising R2 and R5.

[willienillie]

Turn down the volume?  If it comes up too quick, use an audio taper pot.  Then you won't change the sound at all.

[Slowpoke101]

Turn down the volume?  If it comes up too quick, use an audio taper pot.  Then you won't change the sound at all.

I've built a clone of the Katana and it sounds terrific. I agree with willienille that an audio taper pot will be more controllable and preserve the effect's character. GGBB's suggestion will lower the effect's gain, but its tone may change. Try both ideas and see if what happens suits your preferences.

[antonis]

@Gord: Altering R2 and/or R5 value should make no difference in boost mode (i.e. when SW1 closed)..

A brute aproach should be placing a series resistor just before Volume pot Lug 3..
It slightly affects Q2 gain, by raising a bit total Drain resistance (10k//(250k+R) instead of 10k//250k) but it lowers enough output Volume..
(always depending on its particular value, of course.. e.g. for a 10% say of full Volume-up domination, a 27k resistor should be fine..)

P.S.
Altering Volume pot taper should be considered for high value such resistor but it could be compensated by a C taper pot..

[baloubass]

Thank you guys for your reply, i will try and let you know about it.

P.S.
Altering Volume pot taper should be considered for high value such resistor but it could be compensated by a C taper pot..

Can you explain more please?

[jonny.reckless]

Reduce R4 to 470k and add a 470k resistor in series with C4. This will halve the gain of the second stage. You could even then add a 470p cap across the 470k resistor to give it a bit more edge / brightness, a la Marshall JCM800 / Plexi.

[GGBB]

@Gord: Altering R2 and/or R5 value should make no difference in boost mode (i.e. when SW1 closed)..

Yes - you're right - but only for the first stage. Second stage gain should be lower with a larger R5.

For the first stage, instead of raising R2, add another resistor between Q1 gate and the R2 junction with the C3 switch.

A brute aproach should be placing a series resistor just before Volume pot Lug 3..
It slightly affects Q2 gain, by raising a bit total Drain resistance (10k//(250k+R) instead of 10k//250k) but it lowers enough output Volume..

As you allude, that is almost entirely just volume attenuation which can be accomplished with the volume knob itself.

[GGBB]

Reduce R4 to 470k and add a 470k resistor in series with C4. This will halve the gain of the second stage.

Technically, that is lowering the input to the second stage (by volume attenuation), not lowering the gain of the second stage. But it might be the right ticket - worth a try for sure.

[antonis]

For the first stage, instead of raising R2, add another resistor between Q1 gate and the R2 junction with the C3 switch.

Quite right..
By splitting 680R to 220r & 470R shouldn't also upset Q1 bias

As you allude, that is almost entirely just volume attenuation which can be accomplished with the volume knob itself.

Of course, but I'm not sure what OP means by "lowering gain"..
(if it concerns undistorted output signal level or distorted signal waveform..)

[antonis]

P.S.
Altering Volume pot taper should be considered for high value such resistor but it could be compensated by a C taper pot..

Can you explain more please?

By adding a constant resistance to any of outer legs of a variable voltage divider alters its original taper..
(you off-set a variable parameter with a constant one)