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View Full Version : thickening up the mids in a marshall tone circuit

Derelict
05-21-2007, 04:06 PM
i have a peaveyVTM (marshall 2203) that i would like to thicken up the mids in. i almost have it tweaked just right, but the mids are too high. the circuit uses a 33k slope resistor. i want a bit more lower mids for meat. i am torn between either dropping the slope resistor down to around 22k or 16k, OR dropping the mid cap in the tone circuit from 22n to 10n.

thoughts?
JimmyR
05-21-2007, 10:29 PM
What value are the PS coupling caps? If they are .022 you could try .1 - I love the effect it has.
El Caballo
05-22-2007, 12:32 AM
I vote for 16k slope.

Actually I vote for temporarily wiring in a 50K linear pot and tweaking until it sounds right, then measuring the resistance and adding that permanently.
Derelict
05-22-2007, 08:53 AM
What value are the PS coupling caps? If they are .022 you could try .1 - I love the effect it has.

ok..... not quite sure what the coupling caps are. i will do some research and try to find out. i am still pretty green when it comes to these things.
Derelict
05-22-2007, 08:54 AM
I vote for 16k slope.

Actually I vote for temporarily wiring in a 50K linear pot and tweaking until it sounds right, then measuring the resistance and adding that permanently.


actually,
i went ahead with a 22k slope. it sounds nice. i have to run the bass a little lower, but there is definitely a little more lower mid push and less emphasis on the 1-2k range.
El Caballo
05-22-2007, 02:51 PM
actually,
i went ahead with a 22k slope. it sounds nice. i have to run the bass a little lower, but there is definitely a little more lower mid push and less emphasis on the 1-2k range.

Every FMV tone stack has some degree of mid scoop. Lowering the slope resistor raises the frequency of the mid scoop and the overall signal level. If you go too low, you'll get too much bass and your treble control won't do much.

As far as the PS caps, I think jimmyR is talking about the .022 caps coming out of each anode of the PI. .1 is the JTM45 value...it'll make things a bit thicker, though usually at the expense of the same amount of tightness and definition. Definitely a judgment call that depends on your taste and style.