How to connect the Turbo board + 2x Super SC (drawing, post #15) **revised

[stereokillah]

The ratio connections seem fine.

perhaps you have the good wiring but a bad contact, that's why i ask you to check the signal specialy if you bought the kit, cause of the pin connector, i had same problem on two unit and the wire pole ratio had a no contact, and the trubo compressed 2time more than the gyraf.

 

[Alessio]

Everything seems working fine now. There was a mistake in the ratio wiring! :
Thank you everyone for the help.

I have other 2 SIMPLE questions and I hope I've done! ;D

1- On the SSC there are 2 1k2 resistors connected to the meter LED (2k4 total?) if I use a EAO switch with 24V LED should I remove them or at least bring down the value a lot?
2- This can sound silly but... I cant figure out how many amps the fuse should be in order to safe the unit if something goes wrong. This is the transformer I'm using: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=786735&k=62073%20nd
Series Output Voltage @ Current 30 VAC @ 1.2A
Parallel Output Voltage @ Current 15 VAC @ 2.4A


Thank you very much I'll post some pictures as soon as I have the chassis!
Alessio

 

[Harpo]

1- On the SSC there are 2 1k2 resistors connected to the meter LED (2k4 total?) if I use a EAO switch with 24V LED should I remove them or at least bring down the value a lot?

Why will you connect the switch illumination to the meter LED connection at all ?
No such thing as a 24V LED. The LED illumination kit for your switch has a resistor already built in to limit the current for this LED with 24V supply connected. The SSC only feeds this kit by 15V, so brightness will already be decreased. Any additional resistor in series will bring the current flowing thru the LED further down, so you'd probably better use a wire link instead of the 2k2 resistor and connect to the pcb at the 'In LED' spots.

2- This can sound silly but... I cant figure out how many amps the fuse should be in order to safe the unit if something goes wrong. This is the transformer I'm using: http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=786735&k=62073%20nd
Series Output Voltage @ Current 30 VAC @ 1.2A
Parallel Output Voltage @ Current 15 VAC @ 2.4A

So your transformer is a 30VAC * 1.2A = 36VA transformer.
36VA / 115V mains AC voltage = 0.313A
Round up to the next availiable standard value 400mA. Fusing characteristic will be slow blow or T (=time lag) for your toroids higher inrush current.

 

[stereokillah]

Everything seems working fine now.

nice

 

[Alessio]

Thanks Harpo! I absolutely need to study more electronics!!! There are a lot of things that are still dark for me ;D
I made a stereo key input in this unit so if I use only a mono source for the key in it will affect always both channel right? Is not that it will "key" only one channel of the compressor right?

Thanks everyone!


Alessio

 

[Harpo]

I made a stereo key input in this unit so if I use only a mono source for the key in it will affect always both channel right? Is not that it will "key" only one channel of the compressor right?

Yes. This key-in signal will always be the higher-of-two, even with a TS plug and tip only reaching one channel, shield shunting the key-in connecting to the TRS ring of the other channels sidechain down.

 

[ncoak]

does anyone have a comprehensive wiring diagram for this build, or would be willing to supply one? i've been studying the various diagrams in this thread and elsewhere and there seem to be several contradictions...if someone would be willing to definitively answer these questions i'd be eternally grateful.
this is for a permanently turbo'd, 2 sidechain gssl.

here's a simple, point by point text breakdown of what i've got so far/need:

Turbo:
+12V - to Pin 1 (of 10 pin connector on main GSSL board)
0V - to Pin 7 (")
-12V - to Pin 6 (")
[i'm assuming the above involves soldering wires to the underside of the board, as opposed to replacing the existing connections altogether?]

Point C - to Pin 10 (")
SC C.V. - to 100R  near TL072 (on main GSSL board)
S/C input - to the ‘lifted’ end of the 47K resistor on the main circuit board (correct?)

Ratio Connectors x4 to control PCB as indicated in instructions.

----

Super Sidechain Left

EXT/OFF/60/90 etc. to deck 1 of 8 pos switch

COM/OFF/ON to corresponding pad on control board ?
Pot A/Pot B to corresponding pad on control board ?

To SW In/Ret to Bypass Toggle ?

+15/-15/0 to Left VCA rails
L/R/Ret ?

0V/Snd/Ext to TRS jack

---
Super Sidechain Right

EXT/OFF/60/90 etc. to deck 2 of 8 pos switch

COM/OFF/ON - not connected
Pot A/Pot B - not connected

To SW In/Ret - not connected

+15/-15/0 - Right  VCA rails ?
L/R/Ret ?

0V/Snd/Ext - not connected

----

as you can see, the L/R/Ret of each sidechain is the main sticking point, i see it done various ways for different builds and i'm confused as to how to proceed...thanks a ton in advance!

 

[stereokillah]

turbo:
+12V - to Pin +
0V - to Pin 0
-12V - to Pin -

Point C - to Pin C
SC C.V. - to 100R  near TL072 (on main GSSL board)
S/C input - to the return of the second super sidechain board

Super Sidechain Left

EXT/OFF/60/90 etc. to deck 1 of 8 pos switch

COM/OFF/ON to corresponding pad on control board
Pot A/Pot B to corresponding pad on control board

To SW In/Ret to Bypass Toggle

+15/-15/0 to Left VCA rails
L to the pin of one 47k lifted
R to one side pin of toggle switch turbo
Return to the other side pin 47k


0V/Snd/Ext to TRS jack


Super Sidechain Right

EXT/OFF/60/90 etc. to deck 2 of 8 pos switch

COM/OFF/ON - not connected
Pot A/Pot B - not connected

To SW In/Ret - not connected

+15/-15/0 - to same wire as yhe left sidechain in parralel
L not connected
R connected to a side pin of toggle switch turbo
Retrun to the S/C input of turbo


0V/Snd/Ext to TRS jack too

as this pictures ,there is just one error on it the wiring for the turbo switch

so the turbo switch is connected like this

pin1 - R of Left sidechain
pin2 - pin of the second 47k
pin3- R of right sidechain board

 

[ncoak]

great, that's very helpful...the switch wiring there was confusing me a bit.

as this build won't be switchable (permanent turbo), R of super sidechain right will just go directly to the second 47k pin, correct?

thanks very much, that's really helped me wrap my head around it!

 

[AudioguyII]

Hi,


Thx to everyone for the great info,

does this look right?  Keeping it permanent SSC.

L + R are bridged on each SSC board , should the 110R be lifted?

Can I just remove the old bypass rotary switch?

Any ideas why make up gain is always on?

thx so much

 

[aaronmcphee]

Aaahhh I think I got it now.. How about this?

Do I have to make any resistor changes on either of the SSC boards now? 2x 10R instead of 2x 20R on SSC1 (the top one)?


Alex

Well done on producing this excellent schematic, I am at this stage now and have mounted my two ssc's and turbo board into the case. I notice that you do not show any wiring to the rotary switch, is this because its not needed in your example?, or should I still wire the rotary in the usual way? see attached.

 

[lars on]

Hi every GSSL addict !

I have this comp with one SSC working very well.

I'd like to hear the difference  between  stereo side chain and mono side chain.

So I installed a turbo board and two SSC boards following the schematics from @flipside on post #15 of this thread but nothing happened.
There is no difference between Left and Right output compression.

My voltages are good.
My second SSC board is fine and calibrated

Any little help is very welcome.

Thank's a lot

 

[lars on]

Waiting for finding a solution for Turbo + 2SSC, I decided to plug only 1 SSC with a switch for stereo or mono side chain but...

I hear distortion. :'( ???????

I plugged it like holger advise (what I understood) like the pics attached or like this from Reply#13 of stereokillah https://groupdiy.com/index.php?topic=36643.msg450463#msg450463

Few minutes later : I removed the TL074 from mainboard and no distortion anymore.
But I don't think he is damaged because in classic gssl config everything is fine...

 

[SWAN808]

I had a question about the 'Turbo' mod....someone mentioned that the sidechain listens to the signal in the two stereo channels, and the compression then is applied when the threshold is reached on the louder of the two channels, to both channels together equally. Thus this mod is not 'dual mono' compression, it is stereo linked based on the activity of L and R channel. However, I am struggling to understand how this equal application of compression from each stereo channel will be a different result to a summed mono sidechain, given that the sum is based on the L/R channels...can anyone explain this?

 

[PRR]

> I am struggling to understand how this equal application of compression from each stereo channel will be a different result to a summed mono sidechain, given that the sum is based on the L/R channels...can anyone explain this?

If L and R are out-of-phase, the simple L+R sidechain won't compress at all. Two rectifiers will do the right thing.

How often are L and R perfectly out of phase? Well, shouldn't happen, but does.......

 

[SWAN808]

> I am struggling to understand how this equal application of compression from each stereo channel will be a different result to a summed mono sidechain, given that the sum is based on the L/R channels...can anyone explain this?

If L and R are out-of-phase, the simple L+R sidechain won't compress at all. Two rectifiers will do the right thing.

How often are L and R perfectly out of phase? Well, shouldn't happen, but does.......

aha!

That makes sense...having thought about it - it had to be something where the result of the summing process changed something and that totally makes sense...the difference is quite small but that is the sort of small effect....

 

[MiamiBoy]

I've wired the SSC rotary switch following this draw: The voltages seem to be correct...

Hi, this is a very cool way to connect both boards together with the rotary switch.
You also mentioned that if leaving one frequency or EXT. out, it's possible to use a 2x6 rotary switch.
I'm leaving the EXT. position out because of my frontpanel.

As it's hard to find a 7 position switch for my use, I wonder how I can use a 2x6 switch for my 7 connections with the off position being at the switch and not on a button?

Is that possible?
I'm gonna use OFF · 60 · 90 · 130 · 200 · TL · TM -that's 7 positions.

 

[Script]

Could use a two-deck 12-position rotary and just add a few frequencies.

 

[MiamiBoy]

Yea that was my second guess..
The thing is, it gets more complicated, expensive & hard to find, once you go above the standard 12 step 1 deck.

I was wondering if Alessio had a solution, since he used an unusual unique way to connect the 2 boards.

The next best thing, would it be a minimum 7 step, 2 deck ?
if so, do you have a link?

 

[Script]

7/2 rotary seems even more esoteric than 12/2. Maybe take a look at AliExpress. They have some unusual rotaries there, but need to fit into case.

Or could integrate only one filter board for aarhus mode -- no SC filter and no External IN for Turbo mode. Then get a 12/1 rotary and place stopper for 7/1.

Either way you need to work closely with schematics and try to figure out how it it all works to make the right connections. Info is all there.