Marc, a few years ago a top luthier brough me a Bogen tube amp to restore. It was a Challenger CH18. It needed new caps, resistors and an output transformer. I converted the inputs to 1/4" and also now has 4,8 and 16 ohm selectable outputs and a 1/4" output jack for the speaker(s).
As it went, he was strapped for funds and I ended up buying it as well as absorbing the repair bill (almost $300.00). It has sat on the top of my second work station since and I play thru it now and then.
more info:
Year: 1949/1950 Type: Audio Amplifier
Valves / Tubes 6: 6SF5 6SF5 6SL7GT 6V6GT 6V6GT 5Y3GT
Principle Audio-Amplification
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 110-120 Volt
Loudspeaker - This model requires external speaker(s).
from Radiomuseum.org Model: 18 Watt Audio Amplifier CH-18
Material Metal case
Awesome tone and will rival any Marshall when cranked up for tone!
If you are interested I will get some pictures for you. It just sits there and I will never really use it, as I have so many amps I built for myself!
Love to do a trade, if that interest you. As with all old octal preamp tubes they are a bit microphonic! I ordered NOS RCA and they were worse. Will dig those out and throw them in as well.
some pics of one from the net:
