Comments on: Interesting Passive EQ circa 1961 https://www.preservationsound.com/interesting-passive-eq-circa-1961/ information and ideas about audio history Sun, 24 Aug 2025 18:35:35 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: TEAC_256 https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-658115 Sun, 24 Aug 2025 18:35:35 +0000 http://www.preservationsound.com/?p=4452#comment-658115 Not sure if anyone is still working on this or interested, its been more than a decade — but multi-gang switches would solve your issue of sourcing pots with those specs, which you would populate with wirewound resistors designed as potential dividers with equivalent values to several steps of the potentiometers above.

]]> By: opacheco https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-638287 Wed, 03 Apr 2024 21:17:02 +0000 http://www.preservationsound.com/?p=4452#comment-638287 I have done a more clear schematic of the original schematic and if anyone want to check it, please contact to me to:

opacheco_hn@yahoo.com

I would like to analysis this schematic in order to get its transfer function and if someone want to join to this tasks, please let me to know too.

Thanks a lot anticipated
opacheco

]]> By: Oscar Pacheco https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-638286 Wed, 03 Apr 2024 14:15:06 +0000 http://www.preservationsound.com/?p=4452#comment-638286 Do anyone knows how this equalizer works?, are this equalizer balanced equalizer? this look like one balanced unit because we have two lines with passive components and one ground line too.

]]> By: Mack https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-366236 Tue, 16 Aug 2016 10:31:35 +0000 http://www.preservationsound.com/?p=4452#comment-366236 Well sourcing those pots might be tricky…

]]> By: Filipe Zanella https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-254393 Sat, 05 Jul 2014 11:33:45 +0000 http://www.preservationsound.com/?p=4452#comment-254393 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

]]> By: Bastaard Sons of Darius McCollum https://www.preservationsound.com/interesting-passive-eq-circa-1961/#comment-15476 Thu, 08 Mar 2012 22:15:53 +0000 http://www.preservationsound.com/?p=4452#comment-15476 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.

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