GSSL upgrade attempts?

[moonshot]

Hello, I am carefully rounding up parts to build a couple of GSSL compressors and I am wondering if any people have tried upgrading the signal path with different op-amps?

I posed a question last week asking if the original ssl-384 had transformers and learned that it did not so that was enlightening.

I mixed on an SSL console for 5 years and too me the beauty of the compressor was it's ability to make pop music pump. I know that sound is mostly a function of the attack and release constants as well as the DBX 202 vca characteristics.

Still, I have to wonder if the sound couldn't be improved just a bit with some higher quality op-amps. I've seen a posting for someone attempting to servo balance an SSL with 990 style op-amps and I"ve recently seen someone talk about adding jensen transformers.

A lot of this is over my head since I just consider myself a monkey with a soldering iron--laughs. But, if these mods provide a great improvement in sound, I'd gladly pay someone to implement them on my GSSL.

That aside, I'm wondering is if there are easy upgrades that will make a noticeable difference in the audio path?
I picked up some Burr Brown OPA627's under the impression that they should easily retro-fit into the circuit in place of the 5534's. Has anyone attempted using these or any other op-amps? How about the output 5532's? Is there a better replacement for these?
I know all opinions are subjective but if you feel you've improved the sound of the SSL I'd like to hear about it.

Also, I'm thinking that either wima or sprague orange drop caps would be the best to use. Has anybody done comparisons of these and other caps in the circuit?

I apologize if all of this has been covered before.
I have looked most of the posts on the SSL and certain things aren't clarified for someone like myself who is not an audio tech.

As a side note, I just want to say thanks to Jakob and everyone else in this group who is making DIY audio possible!

 

[Svart]

i have opa627's in two of my four GSSLs.. they are much nicer if you are trying to maintain some clarity to your audio, but the effect of the compression really kinda kills the benefit to using them. stick with the 5534.

I used both dual opa627s and opa2604s in place of the 5532. same scenario. you are likely to not hear the difference.

I use panasonic polys and nichicon HE 'lytics in everything.

the only other thing i can think to look at in the gssl is the feedback caps for the I/O opamps. you can decrease the values somewhat and get a little more bandwidth out of them.

 

[spongebob]

i dont know about other opamps in it , but i can measure -70dB k2 after best calibration...of a sine at any frequency...and it sounds a bit crushy....is that a matter of opamps????

 

[regularjohn]

I've used WIMA's and panasonic poly's and panasonic metal film caps...the differences are subtle. 
I'd love to see a gssl pcb stuffed with orange drops!  Good luck with that!  Those things are huge.

I agree with Svart...stick with 5534's and 5532's.  There's not much gain to be made by using different opamps.  There's more gain to be had from using better VCA's (2181A) and properly calibrating the comp for that VCA.
Output transformers will make a noticeable difference.  The lundahl LL5402 are great, much better than the OEP 262A2E.
You'll have to change the output 100R resistors to 22R.

 

[strangeandbouncy]

Hi,


  I've settled for LME49710 + LM4562 instead of NE5534 and NE5532 respectively, after much deliberation. THere is such a tiny difference, but it is there if you know what to look for. Try listening with the 553x's over your mixbus all day, and then swap 'em at the end of the day. Just slightly smoother and clearer. I said slightly . . . .

  I also have decided that I prefer the 100nF caps that bypass the electrolytics on the input and output REMOVED entirely. Ever so lightly less smeary in the top end. I cannot hear any frequency response differences, just less smeary. _ Don't shoot me! That's whaT I THINK. I have also failed entirely to detect ANY differences with different makes of electrolytic. - Again, - Don't shoot me - That's just what I think!!!!


  I have DBX2001 class A vca's in this particular G-SSL.


    ANdyP


     

 

[kilmister]

I've wondered if anybody has tried THAT202R vca's in GSSL?

-Paavo

 

[regularjohn]

Hi,


   I've settled for LME49710 + LM4562 instead of NE5534 and NE5532 respectively, after much deliberation. THere is such a tiny difference, but it is there if you know what to look for. Try listening with the 553x's over your mixbus all day, and then swap 'em at the end of the day. Just slightly smoother and clearer. I said slightly . . . .

  I also have decided that I prefer the 100nF caps that bypass the electrolytics on the input and output REMOVED entirely. Ever so lightly less smeary in the top end. I cannot hear any frequency response differences, just less smeary. _ Don't shoot me! That's whaT I THINK. I have also failed entirely to detect ANY differences with different makes of electrolytic. - Again, - Don't shoot me - That's just what I think!!!!

I have the LME49860's in the mixbuss of my console, so I know what you mean that they're smoother and clearer.  I don't alwas mix through my gssl, so when I do I like it to be a little different of a sound.  I actually prefer using .01uF (10n) bypass caps on the electrolytics, and 100n ceramics on all the psu decoupling.  I feel like it's a little more "air" in the sound...maybe just my imagination. 

 

[reanimatorstudio]

I have not done it but the API compressor has: put  3 vca's in parallel to improve signal to noise ratio

 

[dagoose]

I have not done it but the API compressor has: put  3 vca's in parallel to improve signal to noise ratio

something like this? but then 5 more.  ;D

 

[iangomes]

wowza!!!!

 

[kazper]

You can read a little more about the VCA's pictured above here:
http://www.thatcorp.com/datashts/202data.pdf

There was a PCB layout floating around here once upon a time...

 

[SSLtech]

How to improve a GSSL?

Well I've spent the last 4 or 5 years researching precisely that.

As far as paralelling VCAs, may I modestly point to the 'ultimate' GSSL which I did a few years ago. -There were a total of 34 VCAs in that puppy!

SO... how to improve the GSSL:

1) Turbo. (all the performance improvements of the 'ultimate' version in stereo, without having to buy QUITE so many VCA's!)

2) C/R/C/ board. (Vastly improves noise floor for versions without external regulated DC supply)

3) Use the best VCA's you can afford, and -in the case of manual-trim VCA's, GET THEM CORRECTLY ADJUSTED. (I've heard of a few people spreading falsehoods about the range of adjustment, based on a complete misunderstanding of the data sheets...) Basically, if you don't have access to a distortion analyser, get the pre-trimmed ones.

Keith

 

[SSLtech]

Forgot the link... but here you go:

http://www.groupdiy.com/index.php?topic=18017

34 VCAs:

 

[radiance]

Basically, if you don't have access to a distortion analyser, get the pre-trimmed ones.

I've trimmed mine without one...thanks to you Keith

http://www.groupdiy.com/index.php?topic=21315.0

 

[peat]

Output transformers will make a noticeable difference.  The lundahl LL5402 are great, much better than the OEP 262A2E.
You'll have to change the output 100R resistors to 22R.

I cant seem to get the datasheet for the LL5402 at their website.
It says its an unbalanced drive transformer, just wondering how this interfaces with the gssl output section.
Ive got a diagram for the wiring on the OEP, but not sure about the Lundahl

 

[prescott]

I've used WIMA's and panasonic poly's and panasonic metal film caps...the differences are subtle. 
I'd love to see a gssl pcb stuffed with orange drops!  Good luck with that!  Those things are huge.


Its possible to use orange drops
A nightmare, but possible