Need help with Tone Stack Calculator

[deepmojoman]

Anyone here ever used the Duncan Tone Stack Calculator? I don't know how to figure out the Source resistance and load impedance.

Anyone here know how to do this?

[xtian]

I had a similar question!

Read up:

http://ampgarage.com/forum/viewtopic.php?t=25742

[roberto]

As a source impedance, the options are:
38 kOhm if the eq is plate loaded
620 Ohm if the eq is cathode loaded

The load impedance is usually 1 MOhm when you have only one master volume of 1 MOhm, or 500 kOhm if you have two pots in parallel of 1 MOhm each.

[matt h]

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[roberto]

You are right matt, I referred to the classical 12ax7s plate driven TS with 100k Rp, 1k5 Rk plus Ck, and the other classical CF with 100k to ground, as they cover 99% of the cases.

[matt h]

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[deepmojoman]

OK-thanks for all that info (especially the Preamp Output Impedance Calc-very helpful!)

So: how would I convert the Tone Stack Calc to a single Tone Knob Tone Stack?

[matt h]

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[deepmojoman]

Thanks-which one is BMP? Is that Big Muff?

[The Ballzz]

I just recently played with Tone Stack Calculator for the first time and, IIRC, the source impedance does not have a dramatic effect on the curve generated by changing the other values. I coild be wrong and I'll play with it again when I feel like opening my poor old Mac laptop in Windows.
Gene

[matt h]

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[martin manning]

6db, you say, not a big deal. Until you view that as signal voltage--at which point it's a 4x difference.

Ahem... 2x difference. :^)

[matt h]

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[martin manning]

Voltage goes like the square root of power, -6 db is 1/4 power, (1/4)^0.5 = 0.5.

[matt h]

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