Help understanding 1959SLP reissue post v1b shaping circuit

[SolidStateCircuitReject]

Hi Folks.

Sorry do not know the proper term for this part of the circuit, but after v1b coupling cap there is a series of capacitors and I'd like to know the function. Image attached.

So I know what caps in series and parallel do, but there is obviously a hole in my understanding.  So after the coupling cap between V1b and the gain/volume knob there is a shaping circuit where there is a 470pF paralleled with a .0022µF cap. The circuit then goes on to seemingly bypass the volume pot with a parallel set of .0047µF and a .001µF... and these are in series with another set that contains a 470pF in parallel with a 120pF bypassing the 470k (grid resistor I think? or mixer?) going to v2a.

My logic tells me that I can summarize this to roughly .0027µF in series with a 590pF bypassing the 470k resistor... but I somehow think there is more to it and I am missing something???

Can anyone explain to me?

Thanks!

[sluckey]

I think commonly available values were paralleled to give a non common value. For example, you can easily find a 470pF and a 120pF. But can you show me a link to a supplier that has a 590pF?

[JB]

I think what they've done is taken a particularly good sounding original 1959SLP and measured it.  They're replicating the measured values with parallelled caps.

So it's effectively still the original circuit with a coupling cap, a treble bleed cap on the volume pot and then a treble bypass on the 470K mix resistor.

I guess they're having to measure the caps they're using, given the tolerance of them, and choose ones that match the values on that schematic.

 

[SolidStateCircuitReject]

Thanks!

Okay so I didn't have a hole in my understanding. Great!!!