The Amp Garage

Hey Slim, Congrats on your builds, this is the right place to get some help although the forum is slow these days. Let's try and sort your issues. First the three way neg feedback: the three positions provide very distinct sounds. But it also depends on your speaker. First I would recommend to try t...

Hey W, This is a great start! I love my Tweeddle Dee's around 400 VDC. Higher gets stiffer, not what I like; I tried the MVC where you set it up and did not like it; It changed the sound of the amp too much for me; My preferred setup us a PPIMV La Mar type II. I also hardwire the bright switch and r...

Adding NFB on a switch ala rob Robinette add versatility and options to the 5E3, a must have for me;

Fred.

Indeed! I guess Joe B. Or John M. will add this one to their extensive collection; Bets are opened! The add does not say who is/was the previous owner(s);

F.

She’s a beauty, great documented build! Can’t wait to hear it!

Did you happen to move some cables when you got your amp into the cab? It sounds like a heavy 120Hz buzz.

These could be tricky to find but this one is very obvious and probably one of your heaters or AC run is too close/ parallel to a signal path?

Fred.

Hey Overlandltd, Having built a few dumble clones (HRM, #102, #40, #Bluesmaster clean channel, ultraphonix High gain, and a John Mayer Sig clone), they all have different tone stacks; The skyliner tone stack is very typical Dumble glassy tone (#102), but more aggressive (glassy) John Mayer sig and #...

Hey Ales, Sorry for the late reply, it's been a busy september for me as well; To answer your questions : - Is having individual tone controls what you mean by "uncouple the two channels interaction"? No, if you take a look at the schematic (or the layout), you will see that the volume pots are both...

Congrats on your build, looks great !
Once you get the sting, it is hard to get off of it !
Cheers;

Fred.

Hey AleS, Great project ! I have now built three different renditions based on the "Tweedle Dee"; -1st one had silicone rectification, Cathode bypass + NFB on a switch and the rob robinette cascading gain mod. No low input, only high input and Lar Mar type 2 MV and FX Loop to insert time based FX be...

Yes indeed Bias tremolo.
Now you got me curious to taste the harmonic tremolo
Thanks again for the support, and this great community;

Fred.

Hey Sluckey, Thanks for all the input, I trully appreciate your help; I found the culprit : wired the bias feed of the rectifier tube ... but after the protection diode; No wonder I found the amp was missing bias : there was none ! :roll: Lucky me is using worn out tubes for all my smoke test... jus...

Hey sluckey, Thanks for catching this one ! Yes the cathodes are connected to ground with a 1ohm resistor; Vibrato is working indeed. Smoke test went well, nothing burnt or smelling wrong; Voltages are good but on the bias; I have sound but it feels like I have not enough negative voltage. Will try ...

Amp is finally all wired up ! The build process was challenging as the tubes layout is not ideal to manage efficiently cable runs. Hopefully the amp will remain quiet. I have used a known grounding scheme that worked very well in my previous Tweddle Dee builds. The remaining questions is : will the ...

Been moving slowly but got to get together the preamp board PXL_20250518_204042140.RAW-01.COVER.jpg And finishing the heaters as the donor would not leave me many options PXL_20250518_204008470.RAW-01.COVER.jpg Ran out of eyelets for the power amp board, order is on the way PXL_20250518_204125035.RA...