GGG Silicon Tone Bender mkII thoughts ...

[Steben]

Wouldn't the silicon tone bender mk II (which is IMHO a simply brilliant idea let me tell you) benefit from lowering R1 and R11? This would achieve a somewhat lower input impedance and even more nonlinear response as is found in the germanium original?
R11 really boosts the input impedance as ZbaseQ1 is close to 165 kohms compared to around 2k for a germanium input stage without R. this means the typical treble roll off of a fuzz at full guitar volume is a bit lost. I know lowering or deleting the resistor will cause a gain boost... yet! lowering R1 will bias Q1 more to cut off lowering the response = lower gain.

http://www.generalguitargadgets.com/pdf/ggg_tb_m2p_sc_ns.pdf?fbclid=IwAR12FGvXJb760PCIzNG3Bx3dfZx4x-MCdZ6MEB0qZsgbQDI150rZuCCfL-0

[PRR]

What is the Zin as it stands?

Fed with a linear transducer (pickup), a low Zin will not make it more nonlinear, though it will change the frequency response and level. The low level may even lead to less nonlinearity.

Have you allowed for R10? It looks like total 41k to me. That is low for guitar.

If you are still curious: add a 500k Audio pot across R9, wired to give 50k at center and zero full counterclockwise.

[Steben]

What is the Zin as it stands?

Fed with a linear transducer (pickup), a low Zin will not make it more nonlinear, though it will change the frequency response and level. The low level may even lead to less nonlinearity.

Have you allowed for R10? It l0oks like total 41k to me. That is low for guitar.

If you are still curious: add a 500k Audio pot across R9, wired to give 50k at center and zero full counterclockwise.

Lowering r1 and r11 will reduce Zin and bias, lowering r11 will compensate gain.
Yes, zin a couple of tens of kohms which is more than tenfold that of the germanium. Which means a shift in low pass character.

[Gus]

have you seen this thread?
https://www.diystompboxes.com/smfforum/index.php?topic=114210.msg1059856#msg1059856

The input resistance is close to the Marshall fuzz

[Steben]

have you seen this thread?
https://www.diystompboxes.com/smfforum/index.php?topic=114210.msg1059856#msg1059856

The input resistance is close to the Marshall fuzz

great link, I'll check it out!

[Steben]

have you seen this thread?
https://www.diystompboxes.com/smfforum/index.php?topic=114210.msg1059856#msg1059856

The input resistance is close to the Marshall fuzz

Did the resistor numbers in those discussions refer to the GGG silicon schematic?
EDIT: spice schematic is now visible!