I tried out some different 12AX7s and found a phase inverter tube that could be perfectly DC balanced with the trimmer.

Here is the latest sound clip:

http://soundclick.com/share?songid=6455534

Just to summarize how different or similar my amp wound up being compared to the Overtone:

Different chassis (black adonized aluminum)
PT and OT are Hammond Fender Twin style
Four 6l6 tubes
50/100 switch and LED to indicate 50w mode.
Standby switch wired like a Dumble
Strict adherence to Dumble grounding scheme and lead dress
2 resistors to 'lift' the heater voltage from ground, like Dumble
Separate relay transformer
290uf caps (Dumble had 300uf)
350k OD input trimmer
4.7uf on V2 in place of 1.0 uf
Switchcraft jacks throughout, except FET jack, which is Kobicon.
Ground switch wired with a center off switch.
Main power LED powered with external diode and resistor
4 Bolt carrying handle put on the cabinet
Fender chrome corner protectors put on the cabinet.
Aluminum pieces on front of cabinet replaced to look like original
Once I get my hands on some black Fender grillcloth, this will go on the front plate.

With the exception of a few component changes listed above, and changing the color of some of the wires on the boards, the Ceriatone boards were pretty stock. (The Ceriatone Power Capacitor board was not used)

How important is it to balance the PI? i its something i dont know how to do, nor do i have the eqiupment. I assume you would have to bring up both +and- signals on a oce and match the signals osciloscope.

I have not started dinking round with the tubes in my OTS yet. But I have a lot of experience with the tubes in my super reverb. The biggest variable* factors affecting its tone, and point of break up are the pre-amp tubes (mainly V2 since that is the channel most used) and the PI tube. A balanced 12AX7 in the PI is mandatory. I use JJ ECC83S from Eurotubes. He sells exactly what  he advertises. He tests and categorizes all his 12AX7s. You buy the tube "balanced", the balancing is a virtue of the manufacturing process. Not something that you do to the tube. The 12AX** tube has two halves. On the PI tube each side feeds the output tubes 180 degrees out of phase. It is not important to know what that means, but in knowing that much you can see why you would want the 2 outputs of the tube to be matched or "balanced". I have found this to be very important, especially at higher volumes.

* I am assuming that you will not be changing speakers or other soldered components on a frequent basis. The pre-amp and PI tubes seem to have much more affect on tone than the Output Tubes.

Nice build...sweet sounding amp you got there

Beautiful ic-racer - what a great sound!

I don't have a dedicated speaker for the Dumble yet. I have been using the speakers in the various combos I have. Currently my favorite is a Celestion Modern Lead 70 that happens to be in a Sundown 50w Combo. My second choice (of the speakers available to me) is a 4x10 Alnico set that resides in a Mesa Blue Angel combo. I have Celestion vintage 30s in a 2x12 combo and in a 2x12 closed back Mesa cabinet. Neither sounds real good with the Dumble. So, I'm still looking for the best speaker...

I have a schematic that shows everything! It shows how the 50/100 switch is wired and exactly where it is grounded. The schematic shows all the grounding points. Lead dress was copied exactly from the #124 pictures on the internet. To make it easier I tried to copy the wire colors also (but did not have enough of some of the colors, though)

Lets see if the schematic will post...