I recently built a Tweedle Dee from Charlie Wilson's sketch and thought you guys might appreciate some posts showing the results of my work.
First off, my thanks to all of you - too numerous to mention individually - who helped my thinking on the design with special mentions to Uncle Doug (a real gent. and a great educator) and Rob Robinette who seems to have spent half his life writing webpages
![Very Happy :D](./images/smilies/icon_biggrin.gif)
I was particularly interested in modifying the design to match the 5E3 which permits two channels with hi and lo inputs thereby maximizing the options for jumpering between channels. Another design goal was to keep the sound floor to a minimum. The grounding scheme of separate power and preamp buses was adopted from RobRob's https://robrobinette.com/RobRob_Deluxe.htm design which also gave me the wherewithal to elevate the PT CT voltage, reducing heater hum, by hooking it up to the power tube cathode resistor. As for components, I followed Randall Aiken's advice https://www.aikenamps.com/index.php/res ... -it-matter and went for the largest 'practical wattage' resistors I could lay my hands on, along with an overall increase in the number of metal film resistors. The aim was to produce an amp I could feel comfortable using much more than it was to create a purist clone of a Tweedle Dee, and so far, nothing has exploded and it works like a charm. Only one thing didn't work out, which was to include an ohm selector for the outputs but that was only because of space constraints in the chassis - two dimensional thinking on my part!
As you will see when I post the layout, it pretty much follows the 5E3 organization of components and my board was designed around the components chosen for the circuit. The circuit works for sure, but the position of the tail load resistors (sandwiched between the B+3 filter cap and the power tubes' grid leak cap and resistor network) suggests room for improvement. I think a redesign of this real estate will permit a more logical organization of the components in the signal path and allow for the (physical) installation of an ohm selector.
The tubes (I still call them valves if I am being honest) are the Sovtek 5AR4, a pair of matched EH 6V6GT's and a pair of matched and balanced Tungsol 12AX7's. Generally speaking my voltages are higher than a standard 5E3 and higher than Charlie Wilson's record of voltages from his Tweedle Dee. Everything is still within tolerable limits for the components I think, but my power tube plate voltages are on the high side so I may eventually try swapping the 6V6GT's out for 6L6's. There is very little noise at maximum gain settings: a little AC hum which I might eventually try cancelling out with a Hum Dinger pot and a little pink noise hiss, both of which aren't noticeable once I start to play. I couldn't say what the output wattage is, I would need to sell a couple of these to buy an oscilloscope but it's loud... I mean window-rattling loud.
I built the cabinet as well - a standard '57 5E3 frame with some modifications.
The layout was done in Illustrator. This is just the bare chassis and components.
I'm including a couple of photos of the top and bottom of the board as well.
And the assembled combo. Which will need to go into a subsequent post if anyone is interested as I seem to have reached a limit of five attachments here.
I'm very happy with the build. Nobody died and it sounds rich and authoritative with a gutsy overdrive once the volume gets around 6 on the dial. There is less volume interaction - probably because of the split cathode caps and resistors in the preamp. I'd go as far as to say there is almost none, but that is where the jumpers come in and I'm only just beginning to explore the possibilities there. The speaker is a Celestion Vintage 30. Sounds great. Real ballsy.