Another famous passive EQ

I thought I'd do one more before I turn off the scanner for the night.

Here's a 1950 article by Cinema Engineering president, Art Davis, that includes info on the classic 4031-B equalizer made by his company.

1.5Meg PDF

Ooh ooh..

..is this the groovy looking one in Cyclopedia?

I think they've got a few at Toe Rag studios in London.

Downloading now...thanks for the scans!

:thumb:

(BTW, check your mail Dave!)

Mark

[quote author="Mark Burnley"]
..is this the groovy looking one in Cyclopedia?[/quote]

The very same.

I think they've got a few at Toe Rag studios in London.

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That's what I've heard.

(BTW, check your mail Dave!)

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"Package" received in good condition. Thanks! I've already shared it with the group. :green:

You're really giving today Dave, go man, go! Der skeemos out der in www land somesplace? Thanks for that cool mixer dope too.

:shock: Thanks..!!!!!

Jakob E.

I haven't found any schematics of the 4031-B, but the Langevin EQ251-A (which was reverse-engineered by my friend Rick, and can be found on Gyraf's site) is nearly the same circuit according to most reports. It's been claimed that Art Davis was involved in the design of the Langevin EQ as well.

Shameless plug: the NYD EQ can give you the same curves with much less circuit complexity, albeit with nonconstant input/output impedances.

Did anyone ever find reliable schematics for the Cinema engineering 4031-B EQ?

Jakob E.

I re-engineered a pair of Hycor variant from 2dB steps to 1dB steps for a mastering house, comparing to the 251 was adequate. 

So you would say that the 4031-B is more or less a Langevin 251?

Jakob E.

Yes, outside of small tweaks.  All evidence still suggests Art Davis or his team designed them all.  Cinema, Langevin, Hycor, Altec. 

Anyone have a copy of the pdf? The link is broken.

Cheers

Ian

ruffrecords said:

Anyone have a copy of the pdf? The link is broken.

Cheers

Ian

Click to expand...

Just added to the Technical Documents section. GroupDIY Audio Forum New link below.

I have searched the "1950 article by Cinema Engineering president, Art Davis, that includes info on the classic 4031-B equalizer made by his company" in everywhere and I found nothing at all!...Could someone show me the direct link to please?

Thanks anticipeted!
opacheco