GSSL SuperSC board

[mrcase]

thanks hank!
thats clearing things up for me. gonna try as u suggested!

cheers,
m

 

[mrcase]

me again!  ;D

one more question regarding the 2x ssc with turbo.
I´d like to use the external sidechain feature of the ssc. to which ssc do i have to connect the stereo jack?
both? and if both, what kind of jack do i use? ???

thank you all for your help!

martin

 

[sonolink]

After all your kind replies I must assume my question is plainly stupid then...
Thanks

 

[Stagefright13]

Sonolink. The SSC is an adjustable sidechain filter that allows a variable amount of low end to fly past the detector. So as not to trigger compression. It gives the GSSL a MUCH beefier sound in my opinion. And makes it MUCH more usable on a more varied amount of material. I love it...

John

 

[sonolink]

John,
Thank you very much for replying
I thought the Gyraf PCB had a sidechain already. Isn't that correct? If so, what difference is there between Sidechain and SSChain? The variable option?
Thanks again for shedding some light on this as I'm trying to figure out which mods are worth adding to the AudioKitchen boards I bought.
Cheers

 

[regularjohn]

The Supersidechain is not a sidechain.  It's a sidechain filter.  It is inserted before the sidechain and filters the signal that goes to the sidechain, thereby affecting how the audio path vca's will compress the audio. 

The Turbo pcb, on the other hand, is a sidechain and nothing more.  It will allow you to have a true dual sidechain comp similar to the real SSL comp.  The Gyraf is a single sidechain comp.

 

[sonolink]

Oh I see!!! Makes sense now  ;D
I guess then it's either Turbo Mod OR SSCFilter, right? Or is there a way to combine them to have a true dual sidechain comp similar to the real SSL comp with an added variable filter?
Thanks again for your time

 

[Hank Dussen]

You'll have to use 2 SSC-boards and a dual 12 (or 8) position rotary switch.
There's a lot of info on this somewhere on the forum.
try searching for 'ultimate SSL'

 

[sonolink]

Oh so it's possible to combine it? That's great news!! No wonder it's called "ultimate" 
Thanks for the tip Hank and to the everybody for chiming in
Cheers

 

[regularjohn]

The ultimate ssl actually consists of two gssl boards that are phase aligned to create one stereo dual sidechain compressor.  It was the predecessor to the turbo board (created by the same guy - Keith - who created the turbo board), and does not have any sort of sidechain filter.

The turbo is all you need to have a true dual sidechain comp like the original.  The original buss comp did not have a sidechain filter, so if you're after the "original" vibe there's no need for the supersidechain board.

But if you're going to build one with turbo and a filter, then you need TWO supersidechain boards, one for each sidechain.  This config does not have an official name.

 

[sonolink]

???
Wow!! Now I understand why I got more and more confused this afternoon as I spent a couple of hours reading a few SSL threads

Ok, so maybe it's simpler if I ask it this way:
(1x Audiokitchen board) + (1xTurbo Mod kit) + (1xVuMeterKit) + (1xCRCModKit) + 2x (Gustav Super Side Chain PCBs)=
An "Aarrhus" or "Oxford" stereo compressor with separate L and R variable sidechain ("key in") filter, without noise and able to show Input, Output and GR on the same meter.

Is this correct?
btw, I saw your 22ch "monster" SSL today, regularjohn....nice work indeed!!

 

[tomcat]

Expat says there is no need for the SSC if you use the turbo board. Somebody wrote the same (he doesnt use SSC anymore). Maybe somebody here who has this configuration (SSL + Turbo + 2x SSC) can tell us more?

 

[regularjohn]

sonolink, thanks for the compliment! 

Sounds like you've got the idea now!

The only thing I'd add, is that in the configuration you've got there, you can make each filter independantly variable by using two seperate rotary switches, or you can use one dual deck rotary switch and control them both from one knob.  Just depends how much front panel real estate you've got.

 

[Stagefright13]

OR you could build the GSSL with the super side chain. Wich is totally useful in any studio environment. THEN build another with the turbo board. Why build 1 when you can build 2!!??  ;D

Both will sound different and cover a wider range of audio duties. And buying 2 of everything is A lot cheaper with shipping costs alone.

I like the fact that the super side chain is adjustable in steps. But I haven't tried the Turbo either.

John

 

[sonolink]

Heheheee I already ordered 2 board  ;D

The thing is, I need to be absolutely clear about what I'm going for. Hence my repeated questions on the different mods 

My first idea was to build a dual SSL comp with a switch to be able to use it as A/B or as stereo. Frank at NRG told me I couldn't do this with one board because of the Gyraf design. So I thought I could use 2 boards, building one board "normally" and only one channel on the 2nd board. In the "link" position, the switch would be in true bypass mode (letting the 2nd board out of the circuit) and in the "A/B" position the switch would change the path of i.e.: the Right channel from its input XLR to the second board input. The outputs of the Right/B channels could be combined in a Group Output on the same XLR connector.

But then again, after looking through the forum for other projects that would have the same idea, I thought I might just build 2 units and be able to have 2 mono + 2 stereo GSSLs!! Yes!!  8)

Then I found out about the Expat mods and the Super Side Chain. And then everything got blurry....  ???

I apologize if I am a bit of a PITA asking questions, but I still have a couple of "dark zones" in my mind regarding this 

1) I understand Sidechain as a feature that makes the compressor process audio responding to an external signal. This should imply a physical input commonly labeled "key in". I can't find this input. Am I blind, what am I missing or where am I wrong?

2) I thought that the Turbo mod "adjusted" the way Jakob's circuit behaved by outputting the same GR whether using only L, R or L and R. I never associated it with a Sidechain feature. Again, am I blind, what am I missing or where am I wrong?

Thanks again to all of you for your time and patience 

 

[Stagefright13]

I may be a bit blind myself. I have never used my GSSL on a mono source. Not even once... Couldn't even tell ya if it will do that. And to tell ya the truth never tried.

John

 

[regularjohn]

1) I understand Sidechain as a feature that makes the compressor process audio responding to an external signal. This should imply a physical input commonly labeled "key in". I can't find this input. Am I blind, what am I missing or where am I wrong?

2) I thought that the Turbo mod "adjusted" the way Jakob's circuit behaved by outputting the same GR whether using only L, R or L and R. I never associated it with a Sidechain feature. Again, am I blind, what am I missing or where am I wrong?

1) The sidechain is a vital part of every compressor, no matter if it's VCA, FET, opto, or Vari-mu...and it is part of the internal circuit.  It is a non-audio path section of the compressor that "generates" the compression.  Without the sidechain, you've simply got a line amp.  In the case of a VCA comp, the sidechain VCA creates the control voltage that determines how the audio path VCA's compress the audio signal.  Many manufacturers (including SSL) mislabel the "key in" as "sidechain" creating a confusion among people that the sidechain and external input are one and the same, which they are not ("external sidechain" means "external input TO the sidechain" and not "inputting an external sidechain").  The Supersidechain board has onboard filters so that you don't need an external EQ, but it ALSO has an external send and return ("EXT" setting) so that you can use an external EQ if you want, and since it has it's own send you won't need to mult the source signal. Basically the whole idea behind the external input is to alter the signal that the sidechain "sees", thereby altering the control voltage the sidechain VCA creates, thereby altering how the audio path VCA's compress the audio signal.

2) The turbo board is an exact recreation of the sidechain section that is in the GSSL.  The way the gssl works without any of the mods is that the sidechain sums the stereo signal to mono and uses 1 sidechain VCA to generate the control voltage for the audio path VCA's (the audio path is never summed, only the sidechain signal).  So basically you're using a mono signal to generate stereo compression.  The turbo board adds a 2nd sidechain so that the signal is never summed on the way to the sidechain and each side of the stereo signal is generating it's own compression independant of the other side (This is how the real SSL comp works).  And since each side is doing it's own compressing, you don't get more compression when using both channels because there is no signal summing happening.  In very simplistic terms, the turbo turns the gssl into two mono compressors that are stereo ganged by one set of controls.  Without the turbo, you have a stereo audio path, but a mono sidechain.

And yes, you can use the GSSL with or without turbo on mono sources.  Every stereo compressor on the planet can work as stereo or single mono.  You can even build the gssl as a mono compressor by only populating one of the audio paths and the sidechain.   This is how I did the mono channels in the 22 channel gssl that I built.  And if you stereo link two mono gssl's, you have an "Ultimate GSSL", which is the same thing as a gssl with turbo: two mono comps stereo ganged by one set of controls.

Hopefully all that made sense!

 

[sonolink]

Regularjohn,
thank you very much, that certainly made a lot of sense sense!!

So if I got it right, the Gyraf GSSL with or without Turbo does NOT have an external key in and the SSC PCB has an external input for an EQ, not a "key in" audio signal, correct? If so, is it possible to have a "key in"? Just guessing here, but if I connect an XLR to the EXT return (that would be the labeled "Ext" to the left of the 22u Cap on the left side of the SSC PCB, components side) I should be able to send a signal down that path that would work as a "key in", right?
Cheers

 

[regularjohn]

In order to do key inputs, you need the SSC.  
There are two pads marked "EXT".  One pad marked "EXT" goes to the rotary switch along with the other seven pads near it (TM, TL, 60, 90, 120, etc).  On the left side of the SSC board, there are three pads next to each other that are "Send", "EXT", and "Ground".  This is your external send and return.  They are unbalanced, so you can put them on a single TRS (like a single point console insert), or on seperate connectors - XLR, 1/4", whatever you prefer.  
So if you set the SSC to "EXT", you're sending the audio out through the "send" to your external EQ or whatever you're using, and returning it back via "EXT".  
Or you can use the "EXT" on it's own as a key input, but you still need to set the SSC to "EXT".  If you're only using the return, the ONLY thing going to the sidechain is what's coming in the return.  So if you want to use a kick drum to key a bass guitar for example, that's how you'd do it.

 

[sonolink]

Excellent!! Thanks a lot mate, that's exactly what I needed to know!!

btw I also saw your SSL today (the black vintage nice round VU looking beast)......what can I say? You are one mean DIYer and a real source of inspiration and example to noobs like myself. Thanks again for your time  ;D