MARK IV EQ Scaling

[GainFreak]

Hi,

You all know that those inductors are hard to get. In the same time there's a wide selection of inductors of up to 100mH so I was thinking of scaling down the tone control section by a factor of 10.
The values for the 80Hz section for example will be:

OLD - NEW

470 Ohm - 47 Ohm
1H - 100mH
3.3uF - 33uF
pots 50k - 5k

Did I get it right and do I need to tweak the circuit any firther to make it work with the new values?

[d95err]

Since it's a solid state EQ anyway, perhaps it's easier to use opamps instead of inductors? It should be fairly easy to find a schematic for a generic opamp-based graphic EQ, and adjust it to get the desired frequency bands.

E.g. something like this:
http://www.generalguitargadgets.com/pdf/ggg_eq6b_sc.pdf

[Steve Conner]

You scaled the characteristic impedance of the tuned circuits by a factor of 10, so you'll need to reduce every other impedance in the circuit by a factor of 10 too, and make sure any active devices can source 10 times the current that they had to before, and have 1/10 the output impedance.

The smart money is indeed on replacing all those inductors with gyrators.