Categories: Technical

Interesting Passive EQ circa 1961

Above, a ‘distortionless’ equalizer circuit circa 1961 as designed by one Carlos Moura. Separate bass and treble boost functions (2 frequencies each) and bass and treble loss cut. I do not know the range, frequencies, or insertion loss. Can anyone tell me if/when this was manufactured, and by whom?

chris

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Bastaard Sons of Darius McCollum says:

03/08/2012 at 6:15 pm

I'd plug it into a Spice program and see what it does. You're running with the big dogs when you get into filter design, which is what this is.
Filipe Zanella says:

07/05/2014 at 7:33 am

Gravodisc is a record studio in São Paulo - Brazil and still exists.

This unit seams to be maded for use in this studio and not comercialized I think.

Rgs
Filipe Zanella
Mack says:

08/16/2016 at 6:31 am

Well sourcing those pots might be tricky...