Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: upnorth2 on February 25, 2026, 07:22:16 pm

Title: Danelectro Challenger Series C (1950's)
Post by: upnorth2 on February 25, 2026, 07:22:16 pm

I have a dilemma with a Danelectro Challenger. It was basically gutted by the time it was brought to me, and no schematic on the planet for this amp.   


After a discussion with the owner (friend so parts $ only) it was decided to just build a new circuit, no choice. He wants it to look original and likes a lot of clean. It has two channels with two inputs each and a volume control for each channel, a shared bass and treble tone stack, amplification control (could be a master), and tremolo with speed and intensity.


Original tubes were all octal, a 5Y3 rectifier, four 6V6's, two 12SJ7's and a 6SN7. It would be tough to add an extra tube socket anywhere. The power transformer has a 5v and 12.6v heater tap only. The Danelectro schematics I've seen run the 6.3v tubes from the CT but it looks like these may have been in series with 12.6 volts. 


The tubes I plan to use are a 5AR4, the four 6V6 (two pairs), and three 12SL7's. I added an additional 4A 6.3v transformer for the 6V6's. 


I thought a slightly modified AB763 circuit would work. I could use Sluckey's Trem O Nator and a single triode. I'm not sure of the best way to implement the two volume controls together for a shared tone stack. 5F6A front end? I'd still be a triode short when using the LTP (which is where I want to put the MV)


I build my own boards so circuit mods is not a problem. Wish I could just add a couple of attenuating pots at the inputs of each channel and use the AB763 TS with the volume as a master. Then I could use Doug's bias vary.


Like a dummy after cleaning all the rust off the chassis I built a board with parts I had on hand, but forgot it had two volume controls.


Thanks for any comments.

Title: Re: Danelectro Challenger Series C (1950's)
Post by: glass54 on February 25, 2026, 11:50:52 pm

Hi upnorth2.
This may be a silly question BUT are all the onboard eyelets soldered? Some look a little short of solder, but a nice looking board.
Regards
Mirek

Title: Re: Danelectro Challenger Series C (1950's)
Post by: upnorth2 on February 26, 2026, 06:45:30 am

No, I tack solder parts in place when I populate boards so they don't move around.


They're not in the pic but I made up aluminum mounting brackets to raise the board away from the pots

GW