stereorama 2000 Deluxe into Guitar amplifier

[monfi]

Hello, I want to modify this amplifier that i bought in a flea market into a Guitar amplifier, is a full germanium transistor, that work at 9/12 volt . Is stereo so i'm thinking about use One Channel for high input and one for low, but i wanna drive only one speaker. Can help me for modification? Tnx

[Jazz P Bass]

I am not too sure but it appears that there is a RIAA circuit at the inputs.
It's a compensation circuit for the phono pickup.
That will affect the input as far as a guitar goes.

Could you elaborate on "only want to use one speaker'.

I would not try to bridge the two output circuits.

[monfi]

For "i want use one speaker" I mean bridge it like first image, if is not too much complicated. If it is too much complex i only wanna use only one channel at time but drive only one speaker.
I've found a more resolution schematic (2nd image) and first stage is only the EQ.
So, I hope in weekend I found some time for try to connect guitar and a speaker and try it.

[Jazz P Bass]

I am of the opinion that you should not attempt to bridge the amps together.

See that triangle with the -1 in it?
That is an inverted signal as compared to the Left channel input.
If you want to try to cobble up a circuit for that, be my guest.