Project based on guvnor

[sominka]

Hi
I'm still learning but would this possibly work. I haven't breadboarded it yet.

[GibsonGM]

With a quick glance, it does look like it will work    But, you need to change the point marked "VR" on the output boost transistor to 9V.

Take R8 to 4.5V instead of ground....you may need a resistor between VR and 2nd opamp stage's "+" input, too....10k maybe...but it is probably ok either way.

[ElectricDruid]

What's the point of C5?

Looks to me like it's unnecessary, since the 220n already acts as a DC blocker. Or is it there as tone shaping? (in which case, how?)

Thanks,
Tom

[nocentelli]

What's the point of C5?

Looks to me like it's unnecessary, since the 220n already acts as a DC blocker...

It's a remnant of the original bypass schematic where the output of the first opamp is muted by being grounded after the 10k but the input remains connected to the guitar during bypass.

[antonis]

On the original pedal, one pole of bypass switch was right after R4 (10k) grounding the output of IC1_A..

edit: leo is faster..!! 

<Take R8 to 4.5V instead of ground>
Can't follow you, Sir..!! 

[GibsonGM]

<Take R8 to 4.5V instead of ground>
Can't follow you, Sir..!! 

Yes, another UH OH!      Leave R8 alone...just connect the transistor collector to 9V.

It will bias fine with R8 to ground!!!     

[sominka]

Thank you all for your advice.

[antonis]

<It will bias fine with R8 to ground!!!>

More than fine, I should say, but NOT with current R10/R11 values.. 

Q1 should act as "recovery" stage with no more gain than on tonestack "lost" one..
(OK, maybe with a little bit more..) 

Despite the above, current resistor values result in Collector bias at 3V which isn't close to "optimum"..
A 2k7 value for R11 should settle things closer to my preferance (*)

(*) Closer to yours should be a MosFet booster, of course, so I'm very anxious about chatter resumption..  

[GibsonGM]

Really, if you got rid of the transistor and used a Mosfet boost....   

Yes, thank you, Antonis - the guvnor project should work well now! 

[sominka]

Well this works really well. It's a metal monster. I used yellow LEDs for the clipping and 200k for the Treb as I didn't have a 250k.
2n222A for the transistor.

Thanks for all your help.