Double deluxe tone

[ChrisM]

You might be interested in this piece: http://www.freewebs.com/valvewizard/cathodyne.html

It talks about putting a large grid stopper on the half triode used for the Cathodyne (Concertina) PI in the Deluxe-type circuit.

So on the 5E3 here http://www.kilback.net/homebrewtweaks/a ... _schem.gif

One would put the 100K - 1M stopper in series with the cap going from V2a's plate to V2b's grid?

[Structo]

On the Weber 2 x 5E3 schematic he already has a 1 Meg grid leak resistor but no grid stopper.
I remember some discussion about the small cap between the grid and plate of the 5E3 but I can't remember what it was for, most likely to curb any oscillations.

Interesting what the valve wizard has to say about the cathodyne PI:

A value of 100k to 1Meg is usually necessary. Before you worry, this will not affect the treble response though, because the cathodyne only has unity gain! Therefore it's input capacitance is extremely low, at about 2*Cga + Cgk, which is only 4.8pF for the ECC83! This is the real 'secret' to obtaining a smooth, consistent sound from the cathodyne, no matter what kind it is. If you are using a cathodyne always give it a nice big grid-stopper. The tonal reward is startling!!! Yes I know Leo Fender didn't use any, but he wasn't designing amps to be overdriven, and this is the 21st century.
Believe it or not, the long-tailed pair can also suffer from both of the above mentioned effects (but by different mechanisms), but it is much rarer.
[img:208:284]http://www.freewebs.com/valvewizard/Cathodyne3.jpg[/img]

[M Fowler]

Has it been discussed which KT66's you guys prefer? I only have the one set and want to get some more any suggestions?

Mark

Bruce Collings turned me on to Shuguang KT66s several years ago when I wanted to fatten my tweed Super 5F4. I dig 'em in most everything I've tried.

Thanks Zippy I will give them a try.

[Jammin'John]

I think Victoria came up with the name Double Deluxe, though it's probably something that's been done as one-offs since the 60s.

Yes,Victoria.

JJ

[Jammin'John]

Has it been discussed which KT66's you guys prefer? I only have the one set and want to get some more any suggestions?

Mark

Bruce Collings turned me on to Shuguang KT66s several years ago when I wanted to fatten my tweed Super 5F4. I dig 'em in most everything I've tried.

They had a sale on 'em a while ago at Ruby so I got 2 quads.
Nice tubes !

JJ