PAB mode, adding bass

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Luthierwnc
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Re: PAB mode, adding bass

Post by Luthierwnc »

Completely out of left field, take a look at:

https://tubeamparchive.com/viewtopic.ph ... le+trouble

three or four posts down the author mentions using a trimmer on a switch at the tail of both the mid and bass pots. With a dpdt relay, you can just stick 500k trimmers (wired as vr's) on either side and dial in how much of each flavor you want. I've mostly used just one trimmer at the tail of the mid pot and the bass 10k resistor but the latest built uses both. With one, an enterprising builder could even put the pot on the panel and adjust for different guitars, cabs, SPLs, what-have-you.

Food for thought, sh
Joost
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Re: PAB mode, adding bass

Post by Joost »

I just tested this and I also liked values lower than the 470k, is that going to give me trouble? I even liked the sound of a 100k resistor

also, what side should the foil side of the cap be connected to, the treble pot or the rock/jazz switch? thanks so much again! Great great mod!!

glasman wrote:Here is another little PAB trick.

Shunt the 22M PAB resistor between the Treble and Bass with a 0.01uf cap in series with a 470K resistor.

Still gives a really good boost and gives back a some of the bottom end. You can screw with the R and C values to get different levels of boost and rool-off. Works DYNOMITE on 70's circuits.

I developed this for a customer that a few more nuts on the bottom end when using the boost.

Gary
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glasman
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Re: PAB mode, adding bass

Post by glasman »

About the only thing you are going to loose is boost level. Also remember that as you lower the R you are also lowering the break frequency. I still like a little more boost on the top end than the bottom.

Gary

Joost wrote:I just tested this and I also liked values lower than the 470k, is that going to give me trouble? I even liked the sound of a 100k resistor

also, what side should the foil side of the cap be connected to, the treble pot or the rock/jazz switch? thanks so much again! Great great mod!!

glasman wrote:Here is another little PAB trick.

Shunt the 22M PAB resistor between the Treble and Bass with a 0.01uf cap in series with a 470K resistor.

Still gives a really good boost and gives back a some of the bottom end. You can screw with the R and C values to get different levels of boost and rool-off. Works DYNOMITE on 70's circuits.

I developed this for a customer that a few more nuts on the bottom end when using the boost.

Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification

www.glaswerks.com
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