SSL 4000 EQ

[Vac11]

Sorry I meant "triple gang" concentric. This style:

50KC is value from the "original" schematic (see pdf in attachement), in BOM is 47KC cause these triple gang concentric pots were stock in AML eshop. Value 47K is OK and it will not create any problem in this SSL EQ. The same is 22KB (in BOM) vs. 25KB (in origo shem).

Footprint on the pcb is designed for triple gang concentric pot. But you can use instead of triplegang concentric pot 1x dualgang pot (50KC for frequency) and one singel gang pot (25KB for gain) on this positions... For the Q pot is footprint made for different types of potentiometer legs spacing (Therefore, there is a 9 holes on pcb, but in reality you use only 6 holes).

In "original" schem is:
frequency - dual gang 50K anti log (or reverse log or  negativ log or "C") - 4x per one chanel - you can use 16mm 47KC dual gang from AML
Q - dual gang 10K logaritmic (or audio or "A") - 2x per one chanel - no problem with this pot, you can find it on ebay, or aliexpress,...
Gain adjust - 25K linear (or "B") - 4x per one chanel - you can use 22KB singel gang with center O position from AML

I didnt use concentric pots on my build. I used on one chanel 4x 50KC dual gang pots for frequency, 4x 25KB singel gang pot (or rotary switch with resistor chain) for GAIN +- and dual gang 10KA for Q adjusting (these pots you can find on ebay, or mouser...).

Hope this helps! (?)

 

[Lagrange]

The triple gang concentric pots are definitely the easiest way to fit everything in 1U. Also, if you use separate gain pots, the arrangement of the pots easily gets so tight that it's not as comfortable to adjust the knobs.

The only downside in the Omeg pots is the cost, there was this following quote by iprovlek for 2 channels earlier in the thread. This includes the 4 Q-knobs, but those would be the cheapest ones, so the total cost of the 8 triple gang pots would probably be in the same ballpark.

I was planing to built two of this SSL4000eq that Signalflow share here on forum!
So I contact the Omeg factory and here is the answer:

Hi Ivan

Goods total 140.72
Postage 14.00
VAT 30.94
Total 185.66 GBP

Best Regards
Margaret

Margaret Grantham - Sales Department
Omeg Limited
Imberhorne Industrial Estate, East Grinstead, West Sussex, RH19 1RJ
Tel: +44 1342 410420 Fax: +44 1342 316253 E-mail: [email protected]
Web sites: www.omeg.co.uk & www.castelco.co.uk
Registered In England No: 600441 Vat No: GB 683 4958 82

 

[justinheronmusic]

You guys are so awesome, thank you so much for being so generous with this information. I appreciate you being so accomodating to a newbee like myself.

I took on this build as a challenge to push myself. I am very inspired by Lagrange's build. I think I can contribute to the community whilst achieving my vision for this build.

I will do separate pots instead of concentric pots. Is there a source for 50k dual gang other than Omeg?

 

[Lagrange]

You're very welcome!

I didn't come across any other dual gang reverse log 50k (or 47k) pots  besides the Omeg ones, but those you can order from AML (http://audiomaintenance.com/).

 

[justinheronmusic]

Having a hard time sourcing MKS4D024703C00KSSD .047uf 100V caps. Mouser has two, and I need two more. Mouser has a bunch on back order but no specific receiving dates. Mouser doesn't seem to have anything else in stock with the same specs and a 10mm lead spacing.

Has anyone subbed these out for anything else with success?

 

[Whoops]

Having a hard time sourcing MKS4D024703C00KSSD .047uf 100V caps. Mouser has two, and I need two more. Mouser has a bunch on back order but no specific receiving dates. Mouser doesn't seem to have anything else in stock with the same specs and a 10mm lead spacing.

Has anyone subbed these out for anything else with success?

You don't need a 100V cap,
Search at mouser for 47nf caps from 50V to 100V, I'm sure you will find many.
You can even use 35V

Happy Soldering

 

[justinheronmusic]

Edit:
I solved dysfunctional Q ... It looks like a small bug on PCB layout. When I joined backwards first and third leg on the first deck 10K log potentiometer into the holes on the PCB, everything works as it should .... Q works correctly now. Please keep this in mind and check it out.

I'm having a bit of a hard time understanding what Vac11 meant here. I looked at the picture posted but I am not making sense of it. Can someone dumb this down for my newb brain?

 

[Whoops]

I'm having a bit of a hard time understanding what Vac11 meant here. I looked at the picture posted but I am not making sense of it. Can someone dumb this down for my newb brain?

I don't know if Vac11 means that he swapped the pots legs connections on the pcb.

imagine 123
and maybe he did 321

It's easier if you check the schematic against the pcb holes for that Pot connections, then it should be pretty clear

 

[Vac11]

Yes, i swapped 1 and 3 legs of Q potentiometer....

 

[justinheronmusic]

Yes, i swapped 1 and 3 legs of Q potentiometer....

Did you have to cut traces to do this?

 

[Vac11]

No, my Q pots are joined to PCB with wires. So I swapped wires.

 

[justinheronmusic]

Having a hard time finding 50KC (Reverse) Dual Gang Pots - I've only found them in Law A and Law B. Does anyone have a source? They don't seem to come up on eBay. Looking for as small as possible.

 

[Vac11]

Maybe this?

https://www.aliexpress.com/item/148-double-potentiometer-C50K-handle-length-15MM-20MM-flower/32790271712.html?spm=2114.01020208.3.35.eSEBYd&ws_ab_test=searchweb0_0,searchweb201602_1_10065_10068_10136_10137_10138_10060_10062_10141_10056_10055_10054_122_10059_10099_10103_10102_10096_10148_10052_10053_10050_10107_10142_10051_10143_10084_10083_10080_10082_10081_10110_10111_10112_10113_10114_10037_10032_10078_10079_10077_10073_10070_10123_10124,searchweb201603_1,afswitch_1,ppcSwitch_4_ppcChannel,single_sort_0_default&btsid=2876f66f-5c24-4b16-a4a3-a172c0efc7fa&algo_expid=52348441-f71f-436d-b234-5180d2287b3c-0&algo_pvid=52348441-f71f-436d-b234-5180d2287b3c

 

[Whoops]

Having a hard time finding 50KC (Reverse) Dual Gang Pots - I've only found them in Law A and Law B. Does anyone have a source? They don't seem to come up on eBay. Looking for as small as possible.

You can easily achieve 50K  with a 100K dual rev pot. Just solder a 100K resistor between the 2 terminal lugs, do that for each gang and you have a 50K pot, you can use these links or buy from audiomaintenance:

http://www.taydaelectronics.com/potentiometer-variable-resistors/rotary-potentiometer/anti-log-reverse/100k-ohm-anti-log-dual-taper-potentiometer.html

http://pt.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/P092N-FC25CR100K/?qs=sGAEpiMZZMtC25l1F4XBU%252bXO0%2fntrrgI3gjIKcVXrHY%3d

http://pt.mouser.com/ProductDetail/Bourns/PTR902-2015F-C104/?qs=sGAEpiMZZMtC25l1F4XBUwWjK1Pjsia%252bhngvAYmEIUw%3d

You can also use a 47K dual gang rev log instead of 50K:

http://www.audiomaintenance.com/acatalog/potentiometers_carbon_16mm_diameter_dual_gang.html

http://www.audiomaintenance.com/acatalog/potentiometers_conductive_plastic.html

 

[ilfungo]

Hi
I'm building 2 channel of this EQ.
I need 2 info:
on the boards there is power connection that says 12v ,
It's correct?
It's possible to built all stepped with lorlin switches?
Have someone did this and can help me ( particularly for frequency switch)?
Thanks!!!

 

[Vac11]

+12V is correct. It is power for the relay...

 

[ilfungo]

ok Thanks!
The near pads are for +18 0 -18  ?
thanks!

 

[Vac11]

ok Thanks!
The near pads are for +18 0 -18  ?
thanks!

Correct

 

[ilfungo]

Hi
I'm searching Lagrange * Dual-4k-EQ-faceplate.svg that is not downloadable anymore...
Thanks!

 

[Lagrange]

Hi!

Indeed it seems the faceplate I uploaded is no longer available. Here it is again.

By the way, I heard from a person with quite a good authority on this EQ that if the center detent pots are replaced with non-detent ones, then the gain/Q-curve will be completely different.
Is anyone here able to explain the reason for this? I myself thought that the center detent was simply a mechanical feature in the pot to make the centerpoint easier to find, but I guess this is not the case...