Certain resistors in A15MK2

Hello,

Zitat von polifemo;321983

I need some help in understanding the function of certain resistors in the A15MK2.

- R17: The function of R17 is preventing "popping" when switching channels, right?

correct.

Zitat von polifemo;321983

- R16: What´s the reason for R16? Just a reference to ground, or?

no. R16 and R15 form a voltage divider, which reduces the signal to half of the incoming signal to prevent overdriving the next tube stage too hard.

Zitat von polifemo;321983

- R23: What´s the reason for R23? Just a reference to ground for the boost switch, or?

again, with R28 R23 forms a voltage divider.

Zitat von polifemo;321983

The signal path in the overdrive channel - no boost engaged - from V2a to V3a looks a bit odd to me: 22nF (nothing odd with that!) - R22/470k - R23/220k - R30/220k.

Wouldn`t R22/470k have been enough? Why the extra 2 x 220k?

in the non-boost-setting you have a series of voltage dividers - R22/R24 (470k:1M - reduction to about two thirds), R23/R28 (220k/470k - another reduction to two thirds), and then R30 and R31 (220k/470k,again two thirds).R30 also acts as grid stopper and forms a low pass together with the miller capacity of V3A. I suppose R23 also is for decoupling V2B and V3A.

Zitat von polifemo;321983

There are also 3 resistors to ground in this section of the preamp: R24/1M, R28/470k and R31/470k whose function I find hard to grasp.
Why 3 of them?

see above.

Hope this helps,
Nils