I had a '79 concert bass head that died. I ordered schematics from Fender, see my older posts for the web address.
The packet they sent included schematics for both older (with distortion knob) and new (without dist., like mine).
I can email you scans if you like but they may not be the best quality. Let me know if you want them.
: Here in spain there is no any service for old sunn amps,
: and I need schem for the early seventies concert bass head,
: my beloved one died and must be alive as soon as posible.
: thank you.