DYNAMICS mod

[Nick]

Hi everybody,

here is my shot to the acclaimed dynamics modification by "SSLTech" to avoid the lockup of the dynamic section.
On the output of the 78L15 : solder a diode ( typ. 1N4148) with the Cathode on the output of the regulator, and the Anode to ground. On the output of the 79L15 : also solder a diode, but wire it with the Anode on the output of the regulator, and the Cathode to ground.
Afterwards, when you'll power on/off a channel, the Dynamics cards will always power on, 100% reliable.

Regards








Nick

[marcmozart]

I've seen a lot of posts by "SSLtech" on other forums. Is anybody in touch with him. Would be awesome to get him on board!

The mod you're describing, has this been solved by SSL in later revisions? There is no point to do this on my 1991 G or is there?

[waltzingbear]

Keith is recovering from some ill health right now, on the mend, but it was very real.

Alan

[marcmozart]

Bless him, hope he gets well soon.

[guy_4]

Hello All,
Just for the record, I am the person who informed Keith Andrews ( a.k.a " SSL Tech ")  of this problem, and the solution that I implemented to correct it.
It was a long time ago, mid of the 90's.
It took me a bit of time ( long ! )  before finding why the Dynamics section of some channels of the SSL 4048E were not working after a power Off/On.
And this... randomly...  !   
Originally Keith though it was coming from the electrolytic caps around the regulators that were aging, and cause of the trouble. But it was not.
Because it is an original wrong design from SSL.
The application notes for the 78L...and 79L... regulators specify a reverse diode between the output terminals. ( as for all regulators, generally )
It prevents the regulator to turn its current protection circuit " On"  at the start, and to " lock-up " .
I contacted Basingstoke at this time to let them know of my " discovery ".
I got no return on this, nobody from the factory ever contacted me back, as they usually did with me when technical problems showed.
Along the years I modified several 4K/6K that I met on my service calls, and that showed the problem. ( and that was often known by the studio owners but with no answer to solve it )
I am sure that even today it remains many consoles on the market with this problem...
Best,
Guy

[marcmozart]

Hello Guy,
nice to meet you! Hopefully you find some more time to hang out here - I'm sure you have a lot valuable things to share with the community!

Merry X-Mas,
Marc

[waltzingbear]

Moderators,

This should be made a sticky

Alan

[Artur D'Assumpção]

Welcome Guy!

I'm sure we all have to learn from your experience and I really hope you can find here a community that will appreciate and value your know-how and feedback! And why not, make some awesome new friends!! 

By the way...our get together is due guys!

Cheers,

Artur

[xmax]

Awesome! I always wondered why the dynamics card would do that!

[neumann25]

Recently I found the SSL documentation that explains how to calibrate the compressor... After I calibrated the 82E10 cards using the method written in the alignment procedure, I found it to not give the best SSL compressor sound..and when compressing signals 3-4 db there would that noticable gain difference between compressor channel in and out..  ( this always bothered me cause after compressing 3-4 db I would loose a little signal strenght)

So I decided to listen very carefully on my mastering system, and tune the gain trim marked (0dbm) on the 82E10 circuit board. 
 
I found a really sweet spot just a little off from were the factory calibration ends up being.... Not only does the compressor sound so much more natural, but I can use it on any instrument with much better results.... The fog went completely away, and now the compressor sounds like it has more headroom, and much more neutreal and in phase.. The depth of field is amazing, especially on room mics.. cymbals never sounded so clear.. Tom- toms are to die for.. I also notice when I calibrate it my way, there is not very much audible level reduction when using 3-4 db of compression..maybe  1 db !!
 
I do noticce after calibrating the 82E10 card to my ears, I do loose some compressor gain reduction , and I need to increase the threshold say from 2 oclock to 3 oclock to get the same amount compression.. But the compressor sounds so much better this way..

Just thought I would paste this on this forum , since we are talking about SSL compressors.. anyone have any thoughts on this , please post and let me know.. thanks

[Artur D'Assumpção]

Great tip!! Thanks!! This is what the spirit of this forum is all about!!

[Franz]

Sorry guys, I'm about to make this change and since the letters are deleted, could you tell me if these two are the ones that need to be modified? If so how can I understand which is the input, the ground and the output for both 78L15 and 79L15? Thank you!

[pascal.verdet]

Hi,

The doc is here :
http://repforums.prosoundweb.com/index.php/topic,34948.0.html
Cheers,
P.

[walrus]

Also you need to replace those old Orange capacitors!

[Franz]

Also you need to replace those old Orange capacitors!

Thank you very much guys! After capacitors replacement do I need to calibrate the compressor? If yes, how?