Tweedle Dee on Carter

[Stephen1966]

This amp looks like it may have started life as an Edge signature 5E3, but that's just a guess

I thought the Edge Deluxe came out later, around 2016?

[ijedouglas]

This amp looks like it may have started life as an Edge signature 5E3, but that's just a guess

The pics I have seen of the Edge Deluxe only has 2 inputs. This has 4 inputs. I also would have expected the tube chart to have something on it denoting it as an Edge model (unless HAD reprinted the tube chart)

[ijedouglas]

With some help from AI, we might be able to reverse the b/w filter. This is just with a free tool so I'll keep trying with others and Photoshop neural filters.

Or you could go the other way and take a photo of a resistor and b/w it to see what comes close. ¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯

Very cool! We could probably reference some of those colors back to known values (68K grid stoppers)

[Stephen1966]

Just checked over on Rob Robinette's site and the Edge has .022uF coupling caps to the power tubes, plus 470 Ohm screen grids. I think this amp has them as well.

[Charlie Wilson]

Edge came out in 2016
CW

[Charlie Wilson]

Am I going to ruin the fun if I tell you what the component values are?
CW

[ijedouglas]

Absolutely not

[martin manning]

One example of a Tweedle Dee has been documented already thanks to CW, but I suppose there might be some interesting evolutionary changes in this later example.

[Charlie Wilson]

Actually, the other way around. From what I can see, this is the same circuit as Tweedle Dee #1. So... .02 couplers all around, stock PI resistor values, 10meg/.002uf LNFB, trimmer on plates not cathode and stock 56k/100k plate values, 1k cathode resistors on V1 and the 22uf filter caps. I really think this amp was Dumble's prototype for a Fender production amp. He used 5Y3 rectifier and screen resistors, the stuff Fender probably would have wanted. First one I've seen with F&T electrolytics and again probably something Fender would have used. Never seen a Fender with Ruby Gold. For this amp he used the stock 57 reissue board and added eyelets. There you go, more beans spilled.
CW

[ijedouglas]

Totally makes sense. I was wondering about those F&Ts, never seen them in any amp from HAD.

Always spot on with your knowledge

[Charlie Wilson]

Probably should clarify what is going on with the trimmer. B+ rail comes from filter to bottom terminal of 10k trimmer at the 100k and continues on to V1 off the bottom terminal. The 56k is on the wiper. I don’t know if the wiper and top terminal are jumpered but either way a variable resistance 56k.
CW

[Dr d]

Actually, the other way around. From what I can see, this is the same circuit as Tweedle Dee #1. So... .02 couplers all around, stock PI resistor values, 10meg/.002uf LNFB, trimmer on plates not cathode and stock 56k/100k plate values, 1k cathode resistors on V1 and the 22uf filter caps. I really think this amp was Dumble's prototype for a Fender production amp. He used 5Y3 rectifier and screen resistors, the stuff Fender probably would have wanted. First one I've seen with F&T electrolytics and again probably something Fender would have used. Never seen a Fender with Ruby Gold. For this amp he used the stock 57 reissue board and added eyelets. There you go, more beans spilled.
CW

That's really fascinating, Charlie. Possibly the first evidence of HAD flirting with a production amp deal. Obviously he didn't see it through....but he was tempted!

[Stephen1966]

Probably should clarify what is going on with the trimmer. B+ rail comes from filter to bottom terminal of 10k trimmer at the 100k and continues on to V1 off the bottom terminal. The 56k is on the wiper. I don’t know if the wiper and top terminal are jumpered but either way a variable resistance 56k.
CW

This is a much more effective way of shaping the gain structure in the cathodyne; making the plate load variable, from 56k (balanced) to 66k (imbalanced) all while the cathode bias and tail stays at a fixed 1k5 + 56k. It's very different from the first Tweedle Dee with the trimmer between the cathode bias and tail resistors, where its (much more subtle) effect is chiefly tonal.

I'm also thinking that the voltages in this amp are not going to be as high as in the first Tweedle Dee, stock transformers and only three filter stages with a stock (value) 250 Ohm bias resistor on the power tubes. The sales blurb also says it puts out (the stock) 12.5 Watts which is what you get with the stock test values on the MM transformers and power circuit. Hard to say if he would have changed the dropping string resistors, but on balance I would hazard a guess and say no, he didn't.

So the gain, headroom and maximum voltage swing are all going to be more inline with the off the shelf Deluxe. A 10 Meg frequency resistor in the LNFB is going to compensate for some of that though. If it is 10 Meg.

I'm assuming the cahtodyne still has a 1 Meg grid leak resistor - any counteroffers?

[martin manning]

I'm also thinking that the voltages in this amp are not going to be as high as in the first Tweedle Dee, stock transformers and only three filter stages with a stock (value) 250 Ohm bias resistor on the power tubes.

5Y3 rectifier will make a big difference too.

[Dr d]

Probably should clarify what is going on with the trimmer. B+ rail comes from filter to bottom terminal of 10k trimmer at the 100k and continues on to V1 off the bottom terminal. The 56k is on the wiper. I don’t know if the wiper and top terminal are jumpered but either way a variable resistance 56k.
CW

This is a much more effective way of shaping the gain structure in the cathodyne; making the plate load variable, from 56k (balanced) to 66k (imbalanced) all while the cathode bias and tail stays at a fixed 1k5 + 56k. It's very different from the first Tweedle Dee with the trimmer between the cathode bias and tail resistors, where its (much more subtle) effect is chiefly tonal.

I'm also thinking that the voltages in this amp are not going to be as high as in the first Tweedle Dee, stock transformers and only three filter stages with a stock (value) 250 Ohm bias resistor on the power tubes. The sales blurb also says it puts out (the stock) 12.5 Watts which is what you get with the stock test values on the MM transformers and power circuit. Hard to say if he would have changed the dropping string resistors, but on balance I would hazard a guess and say no, he didn't.

So the gain, headroom and maximum voltage swing are all going to be more inline with the off the shelf Deluxe. A 10 Meg frequency resistor in the LNFB is going to compensate for some of that though. If it is 10 Meg.

I'm assuming the cahtodyne still has a 1 Meg grid leak resistor - any counteroffers?

So not a particularly exciting amp then?!!!