EEQ-12 Elliptic Equalizer Construction Documents

Construction information for DIY projects, including the MS Mid Side Matrix, Width Controller, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
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mediatechnology
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EEQ-12 Elliptic Equalizer Construction Documents

Post by mediatechnology » Sat Oct 28, 2017 2:44 pm

This thread documents construction of the EEQ-12 Elliptic Equalizer.

Elliptic Equalizer EEQ-12 PC Boards: https://ka-electronics.com/shop/index.p ... search=EEQ

Image

Schematics:

Sheet 1: https://www.ka-electronics.com/images/p ... heet_1.png
Sheet 2: https://www.ka-electronics.com/images/p ... heet_2.png

Mouser Project Manager BOM for the EEQ-12 Elliptic Equalizer 12V Relays: https://www.mouser.com/ProjectManager/P ... f06782454f (includes THAT and NJR ICs)
Mouser Project Manager BOM for the EEQ-12 Elliptic Equalizer 24V Relays: https://www.mouser.com/ProjectManager/P ... 470f9f152e
(includes THAT and NJR ICs)

24V relays are recommended if the available relay supply is >24V or the relays are powered from the +/-15V audio supplies.

Board Stuffing Diagram:

Image

https://www.proaudiodesignforum.com/ima ... ut_800.jpg

Preliminary Assembly Instructions:

https://www.ka-electronics.com/images/p ... 2317_1.pdf

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mediatechnology
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Re: EEQ-12 Elliptic Equalizer Construction Documents

Post by mediatechnology » Thu Nov 01, 2018 4:04 pm

Blog post from Ian Stewart on Elliptic EQ: http://ianstewartmusic.us/blog/center-that-sub
KA-Electronics EEQ-12: Among the minimum phase alternatives, the KA-Electronics EEQ-12 is the standout. This analog DIY device, designed and sold by Wayne Kirkwood, manages a 12dB/octave slope without the negative affects of phase shift usually associated with higher order filters. In a nutshell, he does this by compensating with cleverly designed all-pass filter network. If you’re interested in further reading on this device, you can see the design process here. Worth noting, the EEQ-12 tested uses a cutoff frequency of 150Hz rather than the 100Hz setting chosen for all other processors. Even so, it achieves better separation in both the frequency and stereo spaces, and with less phase shift to boot, than any of its 6dB/octave minimum phase elliptical EQ cousins.

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