Picked up a donor amp.......

sparrott · Post by **sparrott** » Mon Dec 12, 2011 7:26 pm

Picked up a donor amp to convert. Came across a Fender studio bass amp with no tubes, rough cabinet, and a bad EV speaker (needs a recone) for $100. After populating with some Mesa 6l6 tubes and eminence 15" legend speaker it doesn't sound too bad, but it is screaming for a conversion. I just don't what which one yet. The output transformer is around 2K plate to plate impedance so I was thinking about running a pair of JJ octal-based EL509 tubes in the output stage to clear up some real estate for the conversion. I have started seperating the head from the cabinet so it is can be carried without seeking medical attention. Any thoughts or input on what to go with?

boldaslove6789 · Post by **boldaslove6789** » Mon Dec 12, 2011 10:13 pm

I got a Doner amp coming too. It's a 72' Twin Reverb.

I plan on gutting it, using the chassis, trafo's and Tube socket's, maybe a few pots. I'm gonna turn it into a SSS with a built in D-lator, 2 tube Verb, Inductor Hi/Low Filter Section, Skyliner Tonestack, Ftsw'able PAB, Reverb, and Fet Boost, 2 tube PI with 12ax7 Driver tube @ 100w via 4x6L6's.

sparrott · Post by **sparrott** » Wed Dec 14, 2011 7:11 pm

Hmmm, interesting. I have some schematics for some high pass networks from a older Altec amplifier that I converted to guitar amp and I believe one of the old Orange 100w amps used one as well. It would take some head scratching on the low filter network. Probably somewhere here there is post describing it.

67plexi · Post by **67plexi** » Wed Dec 14, 2011 9:30 pm

Greg, Sounds like a real tight fit in the Fender Twin chassis, You will need 1.5” extra height, 1.5” depth, 1.5” length if you use stock SSS boards, Or make the power transformer a stand up type, Still tight.

Steve.

Tonegeek · Post by **Tonegeek** » Thu Dec 15, 2011 2:28 am

67plexi wrote:Greg, Sounds like a real tight fit in the Fender Twin chassis, You will need 1.5” extra height, 1.5” depth, 1.5” length if you use stock SSS boards, Or make the power transformer a stand up type, Still tight.

Steve.

I was able to build a #124 variant with built in dlator and 3 relays into my '72 Twin chassis (see pic). I left the FET board out but you might be able to get the FET board on the input end sidewall like HAD does it. You should have room on the back plate for all your jacks. Thing is you may need another supply node for the verb but you could try reusing the doghouse, or use multisection cap cans externally if you need the room. My Twin conversion is my favorite D style build to date. Good luck.

sparrott · Post by **sparrott** » Thu Jan 05, 2012 4:16 am

Did some cosmetic stuff while waiting on parts. Built a head and cabinet from the combo. Using some cheap Ebay carbon fibre look vinyl to cover it for now. Remove the sextet of 6l6's and it is now running on a pair of JJ EL509's. Still makes good power and leaves some real estate for the conversion. Is there a source for SSS turret boards?

sparrott · Post by **sparrott** » Mon Feb 27, 2012 2:17 am

So I have been messing around with a octal preamp version of a psuedo SSS:

6SQ7 -> Tonestack -> parallel 6SL7 stage (blend knob for the parallel tube) -> 6SL7 reverb recovery stage -> 12AX7 phase splitter -> 6n6p cathode follower -> 6x 6l6GC.

I will post pictures, schematics and sound tracks soon. Got to play it tonight at our comtemporary church service, I definitely dig the tone and feal. It takes pedals well. Still need to try a FET input as well.

Tube Amp Archive

Picked up a donor amp.......

Picked up a donor amp.......

Re: Picked up a donor amp.......

SSS..

Re: Picked up a donor amp.......

Re: Picked up a donor amp.......

update...

Tried a interation of the pre-amp