Cassius #10; aka #10 in the the ongoing series of Fender Champ-derived guitar amps built into recycled ‘found’ vintage speaker enclosures. See here and here for some of the earlier examples. #10 is already sold, but will be avail for examination at the upcoming Open Studios event at our building this coming weekend. Cassius #10 is my first ‘Cassius’ with an EL84 output tube: it’s basically the front end of a tweed fender champ married to the power stage of a Vox AC4. Add a nice full-range 8″ Alnico HiFi driver and holy shit does this thing sound great. Solid-state rectifier, no choke, extra filtering stage in the power supply. Output transformer is from a 1950s R GE HiFi console; all other parts are new.
Of all the pieces that I have posted on this website this the past year, the one that gets the most page-views is still my scan of the 1970 ORANGE amplifiers catalog. I’m much more of a large-combo-amp guy then a stack-guy so i’ve never owned an actual vintage Orange amp head. That couldn’t stop me from building one though.
Above, my version of an Orange Graphic 80. Two EL34 output tubes, two 12AX7 preamp tubes, effects loop, variable low-cut filter, adjustable ‘fixed’ bias. Unlike an actual Orange Graphic 80, I used a high-voltage mains transformer and a 5U4 tube rectifier (Orange originally used a voltage doubler and a diode bridge). I also used a slightly different supply for the grid bias voltage as my Hammond power transformer did not have a bias winding. For the output and choke transformers I used pulls from a beat 1950s RCA PA head; it was rated at 30 watts (7027 tubes) so we’ll see how long this output transformer lasts….
The most unique feature of the Orange amps is the bit labeled ‘filter’ here; Orange called it the ‘F.A.C’ control; it’s simply a 6-position high-pass filter that follows the coupling cap before the phase inverter. It’s composed of a 6-position rotary switch with 5 carefully-chosen caps strung in series between the taps. Simple as it is, it does make for a much more versatile amplifier. I recently built this circuit into one of my Cassius amps (already sold) it worked great there too.
Above, the preamp wiring.
Want to know more about building your own Orange Graphic from scratch? Follow the link below to READ ON…