AB763 first channel mids

[C Moore]

I downloaded the Duncan tone stack tool, but I have not figured out how to use it yet apparently.
Anyway....if you are wanting to manipulate Midrange in the Normal Channel of a Super Rev AB763 where is a good/simple place to start?
Can I change the value of the 6k8 resistor that is on lug #1 of the bass pot, other lead of resistor goes to ground.? Or perhaps the 100k resistor between the 250pf and .1uf cap....is that the "slope" resistor?
Thank You

http://www.schematicheaven.com/fenderam ... _schem.pdf

[andyhardy]

There are 2 easy tweeks to try
First raise the 6.8k to a 10k = more bass more mid
Second change the .02 to .047 the.047 is a pretty standard Fender value for lots of ab763 tone stacks

Changing the 100k slope to 150k is a matter of taste.

Cheers

[BTF]

You can actually do both, but changing the value of the slope resistor (the 100K) has a DRAMATIC change on the overall sound of the tonestack. Changing the 6.8K adjusts the mids without adding boominess or boxiness to the sound like tampering with the slope resistor. You can put a 50K pot in place of the resistor and adjust it up and down until you find the mid quality you like, then remove the pot, measure it and install a resistor of that value.

Higher values of the mid resistor may result in a change in effectiveness of the bass and treble controls, but it's easily reversible if you don't like the results.

[BTF]

Forgive me for the repeat of your post, Andy. You posted just as I did.

[funkmeblue]

anyone ever do it like the top hat ambassador? 4.7k resistor in place of the mid pot and a 100k pot from ground to a .047 cap connected to the bottom of the slope resistor.

[C Moore]

Wow!!!
Bing, Bang..... Boom.
Thanks for the answers/ideas. I frequently see the jump from a 6k8 resistor to 10k, but never much in between. Is there not much noticeable change if you were to go 7k5, 8k2, 9k1....? Does 10k just seem to work well?
Thank You

[Jana]

10K is easier to find in the junk box.

[andyhardy]

10k sounds great
Easy enough to desolder the ground and clip in different values
You could also try a 25k mid pot