Help choosing capacitor value.

[jdurango]

I just got a pair of Filmosound 385 projector amplifiers that I'm converting to guitar amps.

Long/short, they both need work. I'll be replacing all power supply caps and 50mfd cap @ input section (they measure low uF and high ESR). The other two lytic caps pictured SEEM to be good in both amps, but they don't match values on the schems I have. As you can see in pics, they are clearly labeled .22 or .2 MFD, where schems say they should be 40MFD and 20MFD (off the 5Y3 tube section). That's a huge difference, factor of x100-x200!!

Since they measure correctly (according to their stated value), my intuition is to leave them in. But I figured I should ask here first. In this circuit, what value would you all suggest? Any other mods I should make while I'm in there?

I do plan to add a 120k pot to the neg feedback loop to attentuate neg feedback to act as a "brightness" or "presence" control. Thanks in advance!

 

[Tubetec]

The two caps in the last picture belong to the part of the circuit you see below , along with the two 1M resistors .

 

[Tubetec]

Theres quite a lot going on there thats not applicable to a guitar circuit ,
Theres equalisation for what ever picks up the sound from the film , I think back then a portion of the film was used to store a picture of the audio waveform , which is then converted back into an audio signal , that circuit is not needed in this case .
Theres also a powerfull oscillator in there , must be something to do with reconstructing the audio waveform from static frames at 25FPS , might be possible to make it into a tremolo osc .