SSL 4000 EQ

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Dubka

Well-known member
Joined
May 1, 2010
Messages
109
Location
London, UK
So, we have the buss compressor, the dynamics section, the mic pre and the talkback compressor...

BUT NOT THE WORLD FAMOUS 4000 EQ?!!

What's the deal?  No schematics?  No interest?
 
Isn't the problem with this EQ that it has odd multi gang pots with different values on each section? Easy for SSL to buy in multiples of 10s of thousands, not so good for DIY.

I wonder if multiway rotary switches could be substituted if the pots set something non critical like bandwidth...
 
I was trying to think of something to work on next, this has been on my "maybe" radar for a while. 

Almost done with the talkback and after that I'm free for something else.  And honestly I'm kind of compressored out - would like to tackle an eq or pre next.  If nobody else wants to take this on I'm up for it (provided I can address the Pot issue - which I think should be feasible actually)
 
I had been thinking about this lately as well...provided I can get a good quote on the pots...let me know if and when you decide Ruckus so we don't tackle the same thing. Especially considering you'll totally whoop my arse on the pcb design and I'd feel like less of a man. lol
 
I had a look at the schems again, the only triple gang pot is in the filters (HPF I think)

The cut/boost pots are centre-tapped (4 terminal), so those would be the problem....
 
MikeClev said:
Isn't the problem with this EQ that it has odd multi gang pots with different values on each section?

Here's what the POT situation looks like for the 611 E/G EQ

47K A/LOG TRIPLE GANG - HF
47K A/LOG DUAL GANG - HMF Freq
10K LOG DUAL GANG - HMF Q
47K DUAL GANG - LF
10K LOG DUAL GANG - LMF Q
47K A/LOG DUAL GANG - LMF Freq
47K A/LOG TRIPLE GANG W/ SWITCH - HPF
10K LIN DUAL GANG W/ SWITCH - LPF

The older versions dont have a switch for the HPF/LPF, so maybe it can just be a separate toggle switch to keep costs down.
 
I looked at the schems on this page:

http://www.ka-electronics.com/images/SSL/ssl_drawings_index.htm

and the HF sections use a dual Alog 50k pot.

On the 82E02, the HPF is also a dual section pot and not a triple.

The 82E02 looks the simplest to copy as there is no electronic switching eliminating a bunch of FETs.

Peter
 
I built up 14 of these several years ago using the original 262 cards, plugged into a motherboard of my design that held the pots and a 241 mic pre, and did not use center tapped nor detented pots.  Worked OK for me. 
Best,
Bruno2000
 
Best Part about DIY is we aren't trying to fit the circuit into a slim channel strip. T think most people would rather use more frontpanel space with easy to find pots, then less frontpanel space with expensive hard to find pots
 
it's great to see plenty of people have been thinking about this one..
does seem kind of crazy we don't have this eq available for diy yet...
especially when you consider the pre is subjectively the weakest part of the 4000 and the talkback compressor is perhaps the least used!
 
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