Tube Screamer with Equalizer

[served]

Hi.

I am building a Tube Screamer from Generalguitargadgets, but i need to modify it so that it has 3 knob eqalizer, could some one help me out with this one?
I preffer Marshal style EQ. I know that i should use Tone Stack Calc but i cant figure out how to do it right.

I hope some one can help me.

Thanks!

[brett]

Hi
you can cut into the signal line just before the output buffer.  The tone stack will have low input impedance (about 1k) and high output impedance (>100k), which is ideal.

Use Duncan's tone stack calculator to choose a stack and resistor and cap values.  Even the standard 3 control Marshall stack is likely to be quite useful.  You should be able to compensate for the tone stack losses by turning up the volume knob a bit.
cheers

[foxx]

Perhaps a look at the Ibanez MT-10 Mostortion will help, a schematic can be found at
http://www.freestompboxes.org/viewtopic.php?f=1&t=1414&start=0&st=0&sk=t&sd=a
Being comparable to the screamer in terms of creating overdrive (with different components though), it has a tone stack inserted in front of a differing 2 stage of the opamp...
greets

[served]

wow thanks.

Foxx could you insert that link again, i cant use it when its dotted.

[ACS]

Hi served, I think the dots represent the 'other' forum that shall not be named here ;p

(Rhymes with 'three pomp sox's'...)

[foxx]

sure, try this
http://i229.photobucket.com/albums/ee166/Benjamin_Bugl/IbanezMT-10Mostortion.gif
this is the direct link to the schematic from the other forum...

[served]

oh i see, didn't know that.
Actually many thanks for the answer, i thought that idea was not so easily to perform. Now i can get to it.

[served]

New question came up.
What should i do with tone knob?
Tone should be one knob eq, now i dont need it any more?

[GibsonGM]

I think the idea is to tap into where the tone stack goes, and replace what's there with the 'new' stack of your design, Served.    You could just remove the existing pot and hard-wire in components that will give a flat response; I'd prefer to remove the existing stack totally, though, and pop in the Marshall one, etc.    You'd have to sort out the Vref connection, but that shouldn't be too hard.   

[aziltz]

I think the idea is to tap into where the tone stack goes, and replace what's there with the 'new' stack of your design, Served.    You could just remove the existing pot and hard-wire in components that will give a flat response; I'd prefer to remove the existing stack totally, though, and pop in the Marshall one, etc.    You'd have to sort out the Vref connection, but that shouldn't be too hard.   

you'd probably need some make-up gain though if you are going for an amp-tone stack.  it might be better to put it between the two op-amps and replaced the tone control opamp with a fixed clean-gain stage.