Tweedle Dee - 4 component mod for Dumble Classic tone stack

[bluesfendermanblues]

Here's a couple of ways you might get all three (I hope!).

Good thinking! I havent put in a switch yet, but was thinking of a phase-reverse switch - from a pickup schematic - reversing in and out, but your idea is simpler (read better) since it doesn't interrupt the signal chain, when switching, and thereby not causing signal plubs in the speaker. Great!

[bluesfendermanblues]

I don't have a Jensen P12R or a Celestion Rocket speaker, so I used a vintage Cel G12 80 Classic Lead I had lying around. However comparing the frequency curves of the Cel 80 and the J P12R .....maybe I'm equalizing my amp (with the Cel 80) to sound like a P12R. Hmmm

http://celestion.com/product/18/classic_lead/

http://www.jensentone.com/vintage_alnico/p12r

I was never to crazy about Alnico's. Don't like the cone cry and presence. And when I first build the amp, I had a Tone Tubby installed. Too peaky.

Am I overlooking something here, in regards to tweeds and alnico?

[galtjunk]

Has anyone implemented this mod.
Is it worth adding?

[Rockwell666]

I tried the classic 4 component mod with the 100k on the input side. Its quite bright but interesting

[Colossal]

I'd like to revisit this topic...very nice work Bluesfendermanblues.

Looking at 10thTX's drawing, I noticed a small error. The series values for the notch should be 100k/220k in Dumble mode, and 220k/100k in Blackface mode. The middle two resistors should be 120k, not 220k.

tnotch.jpg

Second, 4n looks right to create a mid dip at ~460Hz for the Dumble mode, however, with the Blackface Scoop switch adding the second 4n in series for 2n, the scoop disappears. This would give a mid boost. Shouldn't this be the other way around? To increase the depth of the mid scoop, you want to increase the cap value? Or to shift the scoop to the right, you would make the 1.5n bridge cap smaller.