Leak RC/PA preamp

[ggizzy]

Does anyone have a schematic for this preamp? I see the schematic for the RC/PA/U all over the internet, but nothing for its predecessor. I'm thinking about replacing some of these old resistors and caps in this thing to keep it going for another fifty years. I also would like to solder a 1/4" jack into one of the inputs. Thanks for any help.

 

[ggizzy]

As I couldn't find a schematic anywhee on the internet for this unit, I went ahead and diagramed it.

It's been serviced, at least as far as the electrolytics are concerned. However, the resistors and the caps on the rotary switches appear original. I'm going to go ahead and check these to make sure they haven't drifted too much.

Are these caps epoxied silver micas? Do they normally hold up over the decades? Any insight is appreciated.

 

[Tubologic]

Please find below the schematic of the early version of the Leak RC/PA preamp (using the EF40 tube).
The capacitors shown in your picture are wax covered silver micas which are stable and age well, they usually don't need to be replaced.

 

[ggizzy]

Thank you! I couldn't find this anywhere!