Sunking/Klon True Bypass tech question

[Gui113m]

Hi all,

Just a question. By adding the 2M2 pulldown resistor on the TrueBypass/Buffered mod on the SunkingII, aren't we changing the input impedance? If so, how does this affect to the overall circuit?

And last, by leaving R21 and R22 out (sunking), are we changing output impedance?

Thanks!

Sunking/Klon Centaur stock



SunkingII BF/TB mod

[midwayfair]

Yes, you will lower the input impedance from 1M to 687K.

10 feet of cable is 330K for a 20KHz -3dB. How long's your guitar cable, and how good are your ears?

The tone control in the pedal kills more highs than the change in input impedance ever will.

[solderfumes]

I built mine switchable, including the pulldown resistor (not using the switching scheme in the build document but using a 3PDT toggle so I could leave the circuit unchanged).  There isn't much difference at all.  If you're concerned I think it would be OK to change R2 to 2M2 and that would leave you with about 1.1M input impedance.

Someone correct me if I'm wrong, but omitting R21 and R22 won't affect the output impedance.  When the pedal is on, the output shorts R22 anyway, and when the pedal is off it shorts R21.

[mremic01]

Bill used a 2M pulldown resistor in the KTR. To avoid altering the input impedance, he increased the 1M to 2M. So you get the same thing whether it's set to Almost Always Better or Almost Always Worse.

[Gui113m]

Thank you guys!!! Sorry for the delay (family issues, unfortunately)

Bill used a 2M pulldown resistor in the KTR. To avoid altering the input impedance, he increased the 1M to 2M. So you get the same thing whether it's set to Almost Always Better or Almost Always Worse.

Hey Manticorefx, you knowing all about Klons as always! Thanks. IIRC you have traced the KTR, can you say if it has the same schematic as the "Glutton for Punishment" Sunking version? (I mean, R26/R27 out, R3 lowered to 47K, etc)

I'm getting switch popping on my BF/TB Klon builds and I'm curious if the KTR is built that way/does the same. On clean amp settings I can't hear it, but on distorted amp and Reverb at full, there's a loud pop that my other buffered klones don't have.