500/51X Series SLQ51X SSL styled 4000 EQ / Filter

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Just finished my two units, both seem to work as intended on first power up. Calibration of the mid bands was easy, although I still need to fine-tune the calibration of the filters. Still pretty new to REW so gotta get used to it. Went for ~30hz on the lo-cut filters and stock on hi-cut. Both filters cut where they're supposed to, but gotta tune the trimmers so there's nothing else happening 😀

Very nice kits, missing 3 12k resistors in one of them but otherwise all in place.

Enjoyed the chocolates too, not to mention the DI businesscard!
Would definitely recommend and buy again 👍IMG_20210706_025415.jpg
 
Hallo @Kevin
Do you know if it's possible to "improve" the EQ using OPA 604 or similar opamps instead of NE5534. I did this on a GSSL clone and it was great.
 
Hallo @Kevin
Do you know if it's possible to "improve" the EQ using OPA 604 or similar opamps instead of NE5534. I did this on a GSSL clone and it was great.
The OPA 604 seems good, footprint seems to work as supposed, you can leave away the 22pF Caps, but you will need at least 10 OPA 604, if you want to have the Full EQ including filters then you need 16 OPAs.
 
Anyone using these could provide some feedback? I am super interested in that kit but I was not able to find any reviews from users anywhere yet! Thanks :)
 
Hi. I purchased your SSL Style EQ. The Low shelf and high shelf switches are no longer working... Where should i start looking?
 
check all connections and also if switches work. normally there is not so much around the shelf filters. or do you mean the low and high cut?
 
Hey Kevin, sorry if I missed it, but what is the difference between the brown/black knob versions? I believe I saw you mention somewhere that the black knob is a newer version of the design, but I wasn’t clear on what distinguishes the two.

EDIT for clarity - I recognize that these are (I think) based on the SSL variants with the same corresponding knob colors. I guess what I’m asking is, since I don’t have any experience working on an SSL desk of any kind save for ITB channel strips, what are the basic differences in function and circuitry?
 
Hey Kevin, sorry if I missed it, but what is the difference between the brown/black knob versions? I believe I saw you mention somewhere that the black knob is a newer version of the design, but I wasn’t clear on what distinguishes the two.
I totally did two new boards for Brown and Black EQ. My old SLQ51X was a brown EQ just with orange Caps
EDIT for clarity - I recognize that these are (I think) based on the SSL variants with the same corresponding knob colors. I guess what I’m asking is, since I don’t have any experience working on an SSL desk of any kind save for ITB channel strips, what are the basic differences in function and circuitry?
Hey there is some info on SSL Styled EQ on that webpages. The Brown and the Black are in my opinion the most famous EQs of SSL
https://www.recycledaudio.co.uk/consoles/ssl-faq-info/eq-types/https://www.recycledaudio.co.uk/consoles/ssl-faq-info/eq-types/tech-info/
 
Today I had the opportunity to compare Kevin's (Link Audio) built to an 611 SSL EQ. Attached you'll find some REW measurements. As you can see the EQ behaves pretty much as the SSL.
Hi, are these curves the black or brown version? Thanks!
 
Hi Kevin

Just finished the build and are about to start assembly and calibration. Build and instructions was pretty okay so far :)
However, I stumbled across this step, that I would really much like some user-friendly explanation of. I am not a complete newbie - but close to - and I would very much appreciate detailed instructions on how to perform the tests you are mentioning:

"Now we have soldered all parts and want to check without the IC and Opamps installed if the voltages are right. For that we don‘t use the Frontpanel or the bracket.
  1. We use the ribbon cables to connect the boards. CHECK
  2. Use an adapter for your lunchbox/ or power it up on another way. CHECK
  3. Measure all Voltages near the ICs. The Voltage Meter should show something like +/-15,3V, because of the drop of the diodes at the power input.
    Where exactly am I supposed to place the black and red probe of my DMM to do this? At V+ and V- on the IC or at GND and V+?
  4. Check also ifthe LEDs are working. CHECK.
  5. Check that the relais are switching. How do I test this?
Thank you for your help :)
 
Hi Kevin

Just finished the build and are about to start assembly and calibration. Build and instructions was pretty okay so far :)
However, I stumbled across this step, that I would really much like some user-friendly explanation of. I am not a complete newbie - but close to - and I would very much appreciate detailed instructions on how to perform the tests you are mentioning:

"Now we have soldered all parts and want to check without the IC and Opamps installed if the voltages are right. For that we don‘t use the Frontpanel or the bracket.
  1. We use the ribbon cables to connect the boards. CHECK
  2. Use an adapter for your lunchbox/ or power it up on another way. CHECK
  3. Measure all Voltages near the ICs. The Voltage Meter should show something like +/-15,3V, because of the drop of the diodes at the power input.
    Where exactly am I supposed to place the black and red probe of my DMM to do this? At V+ and V- on the IC or at GND and V+?
  4. Check also ifthe LEDs are working. CHECK.
  5. Check that the relais are switching. How do I test this?
Thank you for your help :)
For step three you'd check
1. V+ of IC (red probe) against Gnd (black probe) (should read roughly +15.3)
2. V- of IC (red probe) against Gnd (black probe) (should read roughly -15.3)
 
Hi,Kevin ! I finished my black eq and it works. But I have problem with calibration. No reaction on q-adjust hmf trimmer. What could be the problem?
 
Just finished up three brown knobs. The build was straightforward and calibration was a breeze (instead of REW, I used the sine wave generator in my DAW and a multimeter). I ran some music through them and they are sooooo good!

5BFC8FD8-777D-4339-8D40-5B1046C8B0F5.jpeg
 
Hello. I'd like to start by saying I'm loving the browny i recently built (Considering a second)

I have noticed a curious phenomenon that possibly has an easy explanation. Hoping someone here might instantly know what is occurring.

When I send a line level signal into the CAPI VP28 and then into the LINK. There is a big difference in signal when toggling bypass on the LINK... ~ 10db. I have 2 vp28s and they both do the same thing. I tried different cables, same result.
When i send the signal straight to the LINK the bypass works as intended.

Any ideas?.. cheers
 
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