What an oddity. Is it a storage heater? Nope its a 212 hybrid combo from Germany and by date on some of the caps 1971.
The design inside is completely eccentric, it feels more like a laboratory prototype than a rock amp. There are bus bars for the HT voltage, ground rail and little clusters of modular components featuring the BC109 transistors. The amp chassis lifts up like the bonnet of a car and access to the pots and controls is appalling.
Power stage is a pair of PL84 tubes driven by either an ecc83 or ecc808 depending upon the normal or bass channel. Given that the amp is intended for organs the sensitivity of the input is not suited to guitar so for this client I have adjusted the gain stage to make it suited to the guitars 150mV output.
This is a great piece of musical history and so well made that even after 40 years there is barely anything other than a layer of dust on there to worry about.