Bogen Challenger into Tweed DeLuxe

[CJ]

here is a square dance machine, mic and phono inputs, now with guitar only input

 

[CJ]

original schematic with noisy 6SF5 metal triodes,

we kept the phase inverter and output stage but put in a 6SL7 into slot #1 which had heater wires in the right place (7 and 8)

oh wow, accidently typed the code for a moticon,  we mean seven and eight,

since we have a dual triode, we can ditch tube#2 and use the socket for a terminal strip,

volume #2 was turned into a Baxy tone circuit like the Tweed DeLuxe,

weird 4 pos sw tone circuit was turned into a 4 stage master volume and works great,

 

[CJ]

here is the 5e3 circuit that we stole the preamp from,

 

[andyfromdenver]

since we have a dual triode, we can ditch tube#2 and use the socket for a terminal strip,

oh awesome!  so smart (nerd emoji)

 

[CJ]

here is the four stage master volume, 

resistor values provide clean,  dirty, crunch and  more crunch,

original phase inverter has more gain than the Deluxe, and the 6SL7 tube has more gain than the 12AY7, so we needed a crunch control,

 

[CJ]

here are the guts, B+ too high, about 450, so we keep the knock down resistor only change to 390 ohms at 17 watts, barely gets warm, now we have 425 on the plates so we knock down the screens to prevent meltdown, screens at about 325, still pumping 15 watts or better,

all the CD Tiger caps were leaky and so are the filter caps, clip leads from cap 1 and install dual 33/500 on tight, happened to have a Sprague can  rated at 350 for cap 2,  a couple of 56k dropping resistors prevent over voltage,

4 step master volume used to be feedback tone circuit,

 

[PRR]

Did you keep the vibrator?

Could be handy, your bassist blows the barn's fuse, you can run the guitar from the 1941 Plymouth.