Early (?) Polytone Mini Brute II preamp schematic request

[glebert]

I've got a MBII which I think is pretty early, it has the fuzzy black fabric covering that I think was before they went to the diamond tolex. It has the concentric red distortion knob. It seems to have +/-25V rails in the preamp rather than +/-15V which is what all of the schematics I have found have. Anyone have any info?

TIA.
Greg

[glebert]

CTS speaker date code is mid 1978.

[vintagekiki]

https://music-electronics-forum.com/forum/amplification/guitar-amps/maintenance-troubleshooting-repair/50817-polytone-mini-brute-ii-2-needs-repair

Check IC U7 (LM7815) and U8 (LM7915)

[glebert]

VK, mine is pretty different from the one pictured in that thread, but you made me realize that it isn't +/-25V rails, those are just the "input" side of the regulators. Thanks!

[vintagekiki]

Polytone schematics

https://music-electronics-forum.com/forum/schematic-requests/35586-polytone-schematics

http://schems.com/bmampscom/polytone/

https://el34world.com/charts/Schematics/files/polytone/Polytone_Schematics.htm

https://www.scribd.com/search?content_type=documents&page=1&query=polytone

https://www.scribd.com/document/317298143/Polytone-Mini-Brute-Preamp-Schematic

https://www.scribd.com/document/317298145/Polytone-Lead-and-Bass-Preamp-Schematic

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