GSSL Turbo board complete!

SSLtech

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Hi everyone,

The time has come to pull the wraps off the Turbo sidechain modification board.

A video demonstrating the differences:

The completed board looks like this:
Assembled.jpg


Installation into a previously-built 'normal' GSSL is pretty simple, there is a complete set of illustrated instructions covering installation in basic GSSLs, as well as units which have sidechain rolloff boards fitted.

The board looks like this when it's wired in (not screwed down in this picture):
Installturbo.jpg


I finished up the unit and now the front panel looks like this:
IMG_6520.jpg


(The "turbo" logo is lifted from a Porsche 951, by the way!)

I made three boards and tested them, just to make sure that they work repeatedly and reliably.
Two_Boards.jpg


Prinited Circuit Boards are available from www.expataudio.com and for VCAs, of course the best source to go to is of course Wayne at www.ka-electronics.com.

-If anyone REALLY wants one ready-built and tested, drop me an email, ssltech-AT-Bellsouth-DOT-net and let me know. (since I have two here...)

-By the end of today, there should be a video posted at the expataudio website, showing the difference in compression behaviour between a GSSL (unmodified) and the REAL SSL console compressor. -It then shows that the Turbo board makes the GSSL behave EXACTLY as the genuine article does, having first demonstrated exactly how the GSSL behaves in a COMPLETELY DIFFERENT manner from the genuine article.

If you're looking to 'bolt-on a turbo', please use the links below.

Kits :

http://diypartssupply.com/

PCB's :

http://www.expataudio.com/expatshop/

Enjoy!

Keith
 

SSLtech

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Ah yes. I know that Rochey has just got back from the Far East, and when I spoke to him a couple of hours ago he was pretty jet-lagged and had to grap some sleep, but I believe that he'll get back and fix the site as soon as he's rested; later this afternoon (Texas time).

IMG_6524.jpg


Keith
 

Nishmaster

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Keith,

I dig the Porsche script turbo lettering. Very slick. :wink:

I thought I was cool spotting that, and then as I'm writing this I see you mentioned it in your first post. D'oh!
 

karl j

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Jun 11, 2007
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Seattle!!!
Damn, I thought I was finished with my GSSL! Stop making more add-on options!

Because now I'll have to have one...

Did I miss another thread on this? What does this do differently than the other side-chain?

Thanks,

Karl
 

keefaz

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Nice video :thumb:, it looks like those commercial pro sound tutorials on DVD
I found the test tone maybe a bit loud though (it's probably just me)
 

peter purpose

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[quote author="Svart"]can you explain the differences to those of us who don't have speakers on their work computers?

:green:[/quote]

Double sausage, egg, bacon and beans, with 2 slices.
 

SSLtech

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[quote author="Svart"]can you explain the differences to those of us who don't have speakers on their work computers?[/quote]
yeah... watch it from home! :wink:

Serious-Lee though, the differences are explained in this thread
http://www.groupdiy.com/index.php?topic=18017

..and this one also:
http://www.groupdiy.com/index.php?topic=26428

However, wading through theory can be a lot slower than a simple demonstration of HOW MUCH different it really is.

[quote author="peter purpose"]Double sausage, egg, bacon and beans, with 2 slices.[/quote]

That was my Saturday Morning brekky... oh with Double egg, Three sausage and three bacon... and sautéed mushrooms, Grilled Tomato, and six-cups of PG Tips...

(I'm tryin' to get my accent back, innit!)

Keith
 

matta

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Keef,

What a great video :thumb:

My favourite part is at 4.06 when who I assume is Keef, says 'What am I talking about?', Hah hah!!!! You got love adlibing while trying to A> Film and B> Demonstrate what you are trying to talk about.

A great product and I am FORE SURE going to be adding one to my GSSL. I'm with you on NOT adding a sidechain filter. I did for a friend/client in his but really don't see the value in it, unlike this nifty board.

Kudos to you and Rochey. I hope that Expat Audio continues to grow onwards and upwards!

Svart, RE what the video is showing. It demonstrates that the stock GSSL sums the left and right to mono, therefore tends to be heavy handed with it's compression up the middle of the mix, more so that the Oxford unit.

The board Expat is offering makes the GSSL respond much like the console, with less compression happening when stuff is up the middle and more when material is left and right of the center, just like the console.

Hope that helps!

Cheers

Matt
 

matta

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Hi Keith (I think I'll quit with the whole Keef thing....)

You shared this in another thread:

2181, 2180, 2151, 2150... all perfect for the turbo.

I just tried a 2181, a 2180 and a 2150... I have a 2151 to try, but I fully expect that it will be fine. -Tracking between channels seems to be fine with any of these.

You can mix-'n'-match: my test 'mule' has 2x 2181s for the signal path and 2x 2150s for the sidechains, but I've kept the 2150 in the GSSL sidechain and swapped the turbo VCA with no measured difference in either compression curves or threshold between left and right channels.

Amplitude sweeps for L & R channels overlay perfectly on the Neutrik A2 for amplitude sweep input/amplitude out transfer graphs, which means that I have every confidence that you should be able to mix and match VCAs, although I have a few 2150s in case anyone wants to match them for the sake of reassurance.

As you may know THAT Corp has suggested certain component changes to lower distortion and noise specs when using the 2181/80 replacements, which many, myself included have done.

I assume that these would need to be accommodated for on the Turbo Board if done on the GSSL Sidechain, or do you feel this is unnecessary based on the specs your Neutrik has provided?

Cheers

Matt
 

clintrubber

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[quote author="matta"]I'm with you on NOT adding a sidechain.[/quote]
... filter

Not nitpicking here, just adding what will have been intended but was not typed... :wink:
 

SSLtech

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Matt,

Distortion and noise will not affect the peak envelope of the signal in any way, so while the VCAs in the SIGNAL path will benefit from the correct symmetry etc, the VCAs in the sidechain will not require any such concern.

-In fact this is the reason why the sidechain VCA in the Gyraf version -as well as the original SSL versions- doesn't have a trimpot associated with it. Noise and distortion will -even at worst case- be so far below the envelope outline that they are essentially an irrelevance. :thumb:

Keith
 

matta

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[quote author="clintrubber"][quote author="matta"]I'm with you on NOT adding a sidechain.[/quote]
... filter

Not nitpicking here, just adding what will have been intended but was not typed... :wink:[/quote]

Hah hah!!!!

Correct! I meant to follow sidechain with the word filter... would be funny to see a compressor without a sidechain :green:

Keith thanks for your comments and explanation.

Matt
 

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