AB763 Switchable Mid Cap question

[Soulchief]

AB763 Switchable Mid Cap question:

I have a few model AB763’s (Deluxe, Super, and a Champ) all with .022uF Mid Caps.

All my amps are heads and I use various speaker cabs with all. Some 10”, some 12”.


Question:
Has anybody done a Switchable / Toggle Mid Cap in the these amps to go from the .022 (super) and the .047 (standard) mid cap?


I’m always wondering if both would be beneficial to me using different cabs and speaker combinations..

I like the .022 for the slight mid bump but .047 might help reduce some bass in other circumstances..

I never heard a direct A/B between the .022 and .047 mid but can’t stop wondering.

How is this mod done?


Thanks for any help

[sluckey]

This will do what you want...

[Soulchief]

Oh perfect

Thank you for the View!

[Soulchief]

Quick followup

I made a quick sketch of a potential layout to see if this would work?

Also, would any kind of resistor be needed at the switch for any reason?

layout.png

Thank you again

[WhopperPlate]

Depending on the layout and circuit already in place , you can also just add a series cap with the .05 uf Another .05 uf cap will get you in the ballpark +. You could use .04 uf to get all the way down to that .022 value if you have that odd value lying around .

[Rogan]

I don’t like to leave caps unconnected at one end, so I usually add a big value resistor to connect them to something. In this case, across the switch. 1-2 Meg should do the job.

Probably not a big deal in a relatively low gain amp though. You could try without a resistor first, and add it if noise becomes a problem.