Potential Schematic Difference

[rlyach]

I don't want to call this a potential error but I have noticed that the schematic of the break circuit does not seem to match the wiring instructions. Looking at the schematic, the output transformer should see a variable load from 2.667 ohms to 8 ohms. If I use the wiring diagram, the output transformer should see a variable load from 2.0 ohms to 4.0 ohms. I assume that the wiring instructions are correct and that the schematic was just not updated. Forgive me if I read the schematic wrong.

[Doc B.]

Yeah the schematic looks wrong. The instructions should be correct, and it should be that the OT sees a constant 4 ohms.

[rlyach]

Forgive my ignorance. I have never used an L-pad before. I think the schematic is correct, but it only shows one L-pad and notes that there are two 8 ohm L-pads in parallel, which makes a 4 ohm L-pad. The schematic is just showing the inner workings of a single L-pad and stating that there are two of them. Thanks for the patience.

For anyone who is interested, here is a good description of how an L-pad works.
http://www.bcae1.com/lpad.htm

I was confused because I was assuming it was a simple pot (sorry).

[rlyach]

By the way... I love the break circuit. The other guitar amps I have built used a shunting pot between the push and pull grid controls, but controlling the volume this way affects the tone / crunch and not simply the volume. The break circuit allows you to lower the volume without changing the characteristics of the sound. Very nice....

[Doc B.]

Actually the schemo is a bit misleading. All three legs of the dual L-pads get connected in parallel and each end goes to one of the secondary ends. Those ends that are floating in the drawing are actually connected to the same leg on the other L-pad.

I also think that the brake has less influence on the sound than some other ways of lowering the final output. I won't go so far as to say it's completely transparent, but I think it's about as close as one can get. Better than pillows in front of the cab, anyway.

I have begun picking up a few more speakers that will fit the shallow cabinet, in order to see what we can catalog for different sound qualities in case others want to play with speakers. I just acquired a Weber CVC8 Chicago Vintage. Supposed to mellow out any distortion a bit, and I thought it might be nice with my new jazz box. Also have tried the other style of Weber ceramic Sig8, which i found too bright for this application, and a Jensen Mod8, which IIRC is mellow and has good bass for an 8". Unfortunately the stock cab is a little too shallow for most alnico 8s. I may try to convince Clark to produce a deeper upgrade cab in plyboo that could accomodate them.

I would also love to hear from folks who have been using the Tode with bigger external cabs. I have a 12" eminence (forget the model, maybe legend 1258 or 1218?) that works very nicely with it.

[rlyach]

I agree that the schematic, although correct, is a bit misleading. You have to know that the two resistors shown are actually inside one of the L-pads and not representative of both L-pads. The resistors / pots inside the L-pad actually hang open just like they are drawn. Perhaps drawing a box around both resistors or explicitly drawing both L-pads might clear up the confusion.