Turbo Gssl help please..

[SSLtech]

[quote author="flight"]This is incoming from 100R and cant be 12 V ! :!: :?:[/quote]
I fail to see exactly what you mean by this... I'm sorry.

Keith

 

[flight]

Hello Keith ,
I mean this is where the turbo card is plugged from S/C C.V point from Gssl . no ??
Sorry my bad english translation keith ! :wink:

Maybe i didnt really undestand all ! :roll:

 

[bassculture]

hi flight !

i guess ralph's comp is not finished yet....

are you done with those problems ?

stupid question :
did you delete resistors that should be, to use that 2181LA ?
(i mean 10K & 47R)

did you connect the supersidechain board ?

let me know, i'll enter the test phase this week or the next one

 

[Dr nEon]

Hi everyone!

Just jumping in to say I've just finished wiring up a nu gssl with the turbo board , and it's FABULOUS :grin:

Just one thing I'm curious about tho'..with regard to the 127k ratio resistor..

I've done three ssl's now , ALL with 2180LA's

In the first, a straight GSSL (no turbo) 127k gave me correct ratios

In the next , keef's 'ultimate' dual board version, both boards needed 118.7k for correct ratios

And now , this new TURBO'd GSSL seems to want a 100k resistor to bring me to the correct ratios.. At first I tried a 127k , but the ratios were WAY low..10:1 was actuallly about 3.6:1 . 100k brings me pretty spot on.

Does this sound correct?

Any of you guys out there who have completed turbo builds with 2180's...what did you end up using?

Oh,.. I should add that on my earlier builds I left out the famous 10k&47r 's on the sidechain , but this time around I followed emperorTK's advice , and included them on the both the main and turbo boards. I don't think this would influence the ratio resistor value though , would it??

All thoughts appreciated , and big cheers to Keef/ Rochey & Jakob of course!

nEon

 

[Dr nEon]

Sorry to bump this guys, but this is a call out to anyone who has added the turbo board to a GSSL using 2180LA vcas..

Have you checked your ratios?

A while ago it was established that the 100k resistor should be upped to 127k when using 2180s in a gssl.. and that worked for me..

But now with the turbo added , I need to go back down to 100k to have correct ratios.

I'm studying schemo tryin to work out if this is happening because of adding the second sidechain , or if I have a fault somewhere ..

I'm going thru SSLtechs troubleshooting notes , and haven't found anything odd yet ... :?

cheers

nEon

 

[marshman]

If I remember right (and that is a gamble) I ended up with around 105k or something like that for correct ratios. But I was thinking that was because I had the original 202's in the signal path.

I built one with all 2180's and I think it was pretty close with 120k, but it has been a while.

All three units have the turbo boards and LED meters.

mm

 

[Dr nEon]

Hey, mm, thanks for the response..

I built one with all 2180's and I think it was pretty close with 120k

This was measured after the turbo was fitted , right?

I was near that value too with my dual board 'ultimate' version ..118.7k did the trick then. So it was a surprise to find the ratios so low on this build , when using 120k.

It's weird that (..coincidentally?) 100k should be 'bang on' ratio-wise for me now while still using 2180s.

I took my time , as usual ,carefully matching every single component value , between channels , and I can't find an error anywhere. Both channels seem very well matched in terms of i/o level ,and gain reduction response. I've tried the ratio tests while running in both single and dual side chain modes(oxford/arhuus) , and I've also tested L & R independently as well as both channels ,of course ,just to see if I can find an imbalance somewhere , but I'm getting the same ratio results however I test. I'm starting with around 8dB reduction showing , keeping it away from the knee..

I can only think of trying to swap out the TL072 to see if that makes any difference..

Any more 2180 turbo buddies out there??

Cheers again marshman!

nEon.

[/quote]

 

[marshman]

This was measured after the turbo was fitted , right?

well, yes. All I had at assembly time was 120's so I dropped one in to get it going. I just figured I would replace it after measuring the ratios, but did not have to with all 2180's. It came out very close.

mm

 

[Dr nEon]

Ok thanks marshman for confirming that!

Well it's starting to look like I do have a problem here with my unit , then.

I need to find the exact cause of why my ratios were so low with 120k in there...

..any ideas most welcome!

Cheers

nEon

 

[Dr nEon]

OK , trying not to beat myself up over this , but I still don't feel close to a real solution...

I've read and printed off various forum pages , including SSLtechs brilliant guides..

In general , all my "signal present" AC voltages appear to behaving as expected on the TL074 pins 1,7,14 , but I HAVE spotted one weird anomally which seems to be contrary to Keiths readings:

With silent input , DC voltages at TL074 Pin 1 : main reads +0.135v , turbo reads -0.084v

while at Tl074 Pin 7 main and turbo both read 0.001v


And according to Keiths notes :

Main PCB pin 1 voltage Turbo pin 1 voltage
+0.005V -0.002V

Main PCB pin 7 voltage Turbo pin 7 voltage
-0.053V +0.088V

Turbo pin 8 varies between approx. 0VDC and +2.5VDC as the threshold control is turned through its complete range of travel; Approx. +1.2VDC at the mid point.

From this, we can see that pin 1 should have basically no DC present (which makes sense), pin 7 can have some DC present, maybe in the region of ±100mV

..which is all seemingly opposite to what I have , suggesting I have a problem indeed. (excluding turbo pin 8 which measures correct) ...But I don't know if this would cause my ratios to be so low..

Also ,another observation: measuring ratio resistance across the 1M resistor for 2:1/4:1/10:1 gives 195k/292k/613k respectively . Should these values be higher??

The quick fix would be to just go ahead and use 100k instead of 120k, for the correct ratios , but I don't really know if that would ultimately be a safe thing to do...

any thoughts, anyone?


Cheers

neon

 

[Chrome Heart]

This may be a dumb question, and probably is; but when connecting the turbo board to the control board, do I just solder to the pins of the lorlin switch on the back side of the board? Does the existing connection at the header get removed when connecting the "C" wire to the main board. Sorry of this is a naive question but there doesnt seem to be as much detail about the turbo board as the gssl.

 

[SSLtech]

Yes, you just solder to the back of the switch pins as you correctly guessed, and no, you don't remove any connection to point 'C', -you just add a solder connection to point C, so that the control voltage gets added to the existing circuit.

Keith

 

[Chrome Heart]

Thank you Keith. Your very helpful, and it is much appreciated.

 

[rrs]

Hi and thanks for this Turbo add on Keith.

I have built two turbo GSSL's and 2 Non Turbo's.
Now with the turbo units they seem too compress quite hard. That is the attack seems to hit like a transient designer attack set on stun. Both sides seem balanced and have compared all my GSSL's with audio samples from an actual SSL Buss Compressor so I know this is not normal. My non turbo GSSL's sound great.

Can anyone suggest where to start looking to track down the problem?

 

[SSLtech]

Can anyone suggest where to start looking to track down the problem?

Right here, and go step by step.

Keith

 

[bassculture]

hi all

i solved my problem... (turbo side compressing more than the normal side)
finally the trouble was :
on the turbo board, on the ratio connector, pin > "pole".
the solder is under the board, the track is on top.
there was no contact beetween solder side & track (upper side)... haha tricky...

not the thing i would thought first, quite hard to find !!! (like 6H...) triple check everything...

the Keith troubleshooting helped me narrowing down things - thanks

my other turbo board (in another comp) doesn't have that problem... so i suppose i just got the one with a default

 

[schrobbelbop]

Hi!

my problem is that the turbo board compresses way too much.
it seems that the threshold range is not good. could this be a
broken 074?

Or do i have to adjust resistors cause its comming with 2180 instead of
2150. (already removed 47R and replaced 3k9 for 5k1)

 

[regularjohn]

Hi!

my problem is that the turbo board compresses way too much.
it seems that the threshold range is not good. could this be a
broken 074?

Or do i have to adjust resistors cause its comming with 2180 instead of
2150. (already removed 47R and replaced 3k9 for 5k1)

It should have the exact same resistance values as the sidechian on your gssl.  Any resistor value changes you made to your gssl sidechain should be done to the turbo as well.

Question: You are using the same vca in your gssl sidechain as in the turbo, right?

 

[schrobbelbop]

Hi!

my problem is that the turbo board compresses way too much.
it seems that the threshold range is not good. could this be a
broken 074?

Or do i have to adjust resistors cause its comming with 2180 instead of
2150. (already removed 47R and replaced 3k9 for 5k1)

No I don't it's 2181B for the audio vca/sidechain and 2180 for the turbo.
I changed only the 100K for 120K for ratio adjustment in the sidechain.

All other resistor changes are on the audio vca's.

It should have the exact same resistance values as the sidechian on your gssl.  Any resistor value changes you made to your gssl sidechain should be done to the turbo as well.

Question: You are using the same vca in your gssl sidechain as in the turbo, right?

 

[regularjohn]

Considering the turbo is just a copy of the gssl sidechain, I would recommend that when they are built, they are built with matched components so that both sides are identical.
You can buy just the pcb with no components from Expat Audio, that way you can put in your own components.  I personally would never use two different vca's for turbo/sidechain purposes.

Did you test each resistor before putting them into the turbo?  Could be you've got a wrong resistance value somewhere.  Unless you put the TL074 in backwards and powered on, it's unlikely that there's anything wrong with it.