GSSL HELP THREAD!!!

[darkus]

I have been using my unit for years with pleasant results but I do have one strange issue. Every once in a while after I power it on, it will not pass signal, the meter and lights appear to be working as usual but I get no output. If I simply toggle the power switch, it comes back no problem and everything is fine. I'm very tempted to leave well enough alone because it happens quite rarely and it's a quick fix but I would like to figure it out eventually. Any ideas?

Read what i wrote just few replies above. Replace 7815 and see if it fixes it.

 

[jordan s]

Thanks, I'll try it out.

 

[rosestudios]

@Che_Guitarra:


Hello,


looks like you're really confused about this topic,same as a lot of others here.


I'll try to explain it as simple as possible.


The original SSL bus compressor has two sidechains already while the GSSL has one.
Adding the turbo board adds this second sidechain to a GSSL build.
The hpf filter might not be needed if you run it especially in the original two-sidechain or "Oxford"-mode.
Why?
Because in "Aarhus"-mode (or one summing sidechain) as per default the coherent signals mainly in the bass
frequency area will add up to max. +6dB (in theory) and will therefore force the unit to compress stronger than if it will with a second sidechain.
This is why the sidechain filter boards came up to compensate it a bit.
The original SSL doesn't have this filtering provision,but if you want to make your compressor more versatile you might want to add filters.A matter of taste or needs I'd say.
So no,there's no need for filters in turbo mode,but could be done.
If so you'll need two identical hpf filters or filter boards (one for each sidechain).


I hope this cleared it up a bit,


best regards,


Udo.


Edited typo.

Hi, I asked earlier about the switchable turbo or sidechain wiring, rather than having sidechain available on both modes.  I found this topic http://groupdiy.com/index.php?topic=36643.0 but I am not sure which of these diagrams is correct?  Perhaps you could shed some light on this seeing as you have some understanding of the mod boards?

Thanks, really hoping to be able to switch between the default GSSL mode and use the sidechain for it as well as having the classic mode without the sidechain.

 

[kante1603]

Hello,


so you want both,the turbo without filters and Aarhus-mode including filters,do I get it right so far?
Personally I only did the turbo-modification,adding the filters therefore is useless for me and my demands.
I can't answer your questions about the filter board and its' wiring,sorry.Maybe other guys here can chime in?


About your last sentence,I think you get it wrong:
A mode without sidechain will never work.
GSSL-mode has one sidechain ( the left and right signals are fed and summed up to one sidechain input via two resistors),Turbo- or Oxford- or Classic-mode has two sidechains meaning each signal has its' own path (just different names for the same thing).


If you still want to have both options please refer to expats' nice pdf,start at page 9 here:


http://expataudio.com/diy/Turbo/TurboInstallationManual.pdf


Hope to have helped,merry xmas,


Udo.

 

[rosestudios]

Your first question is correct, I'd like to see how to get Turbo without SSC and Aarhus mode with SSC.  Sorry for my mistake for wording in my post, replace instances of "sidechain" with SSC in the final part, I understand that obviously compressor units must have a sidechain detection. 

Hoping someone saved stitch-o's old diagram, his has been lost to the internet and I'd really just like to figure out the DPDT wiring, not sure if the crude diagram in that link provided halfway down the page does the justice. 

Happy holidays all.

 

[Script]

Possible turbo and/or SSC configurations:
http://groupdiy.com/index.php?topic=35450.msg445603#msg445603

['Aarhus']
(1) GSSL (basic)
(2) GSSL + SSC (1 x filter)

['Oxford']
(3) GSSL + Turbo
(4) GSSL + Turbo + SSC (2 x filter)

Once you have a working 'Aarhus' GSSL and want to 'step up', I'd advise building the whole thing (Turbo plus 2 x SSC). Maybe two SSCs is overkill, but definitely useable. And you can always turn the SC filters to 'off'.  Here's a good starting point -- also in that thread should be a link to VCA 2181 etc  types and necessary changes.
http://groupdiy.com/index.php?topic=35450.msg508471#msg508471

P.S.: Having to read 300+ pages to get a single unit up and running ain't no rite de passage into DIY any more -- it's torture

 

[frazzman]

Does anyone please have the Gerbers for the rev 11 boards

 

[rosestudios]

Possible turbo and/or SSC configurations:
http://groupdiy.com/index.php?topic=35450.msg445603#msg445603

['Aarhus']
(1) GSSL (basic)
(2) GSSL + SSC (1 x filter)

['Oxford']
(3) GSSL + Turbo
(4) GSSL + Turbo + SSC (2 x filter)

Once you have a working 'Aarhus' GSSL and want to 'step up', I'd advise building the whole thing (Turbo plus 2 x SSC). Maybe two SSCs is overkill, but definitely useable. And you can always turn the SC filters to 'off'.  Here's a good starting point -- also in that thread should be a link to VCA 2181 etc  types and necessary changes.
http://groupdiy.com/index.php?topic=35450.msg508471#msg508471

P.S.: Having to read 300+ pages to get a single unit up and running ain't no rite de passage into DIY any more -- it's torture

Noo, this isn't completely true, there's another (apparently fabled) mode that is Aarhus/Oxford with one Turbo and one SSC board, seen in these threads:

http://groupdiy.com/index.php?topic=32341.0
http://groupdiy.com/index.php?topic=36643.0

However the crucial diagrams have disappeared and I'm still requesting that some expert contribute knowledge on this in terms of specific wiring to a DPDT switch (I believe Holger used a relay) or if perhaps they've saved the essential diagrams.

 

[baol]

Hi, just a question: do the 2180B too need the 4th pin bended? for all the 3 vca?
thank you and happy new year

Andrea

 

[icemanaman]

Hi guys,

Just a quick question about the gssl makeup gain:

The makeup gain knob on my unit is affecting the signal gain even when the unit is in bypass mode and because of this I can never level match my signal between bypass and non-bypass. Is this normal?

Thanks,

Jim

Hi guys!
I am having the same problem. I also have the NRG switches and they are wired the same way as described earlier.
Can anyone confirm that the the alternative switching provided by Gyraf on page 336 works?
Just thought I would ask before I started messing around with stuff.

Thanks!

 

[Zander]

Hi,

Quick question: Can is use two conductor shielded cable for wiring the pots. Not sure if the capacitance induced from both connectors to shield comes into play in this application?

Zander

 

[gyraf]

Don't use shielded wire for the pots - they do not carry audio, only DC voltage.

See schematic.

Jakob E.

 

[Zander]

Don't use shielded wire for the pots - they do not carry audio, only DC voltage.

See schematic.

Jakob E.

Hi,

Thanks for answering so promptly. It's not from a functional (read: reducing interference) point of view. More for cable management...  The shield would carry the wiper to both TL072.

Zander

Zander

 

[ding]

Your first question is correct, I'd like to see how to get Turbo without SSC and Aarhus mode with SSC.  Sorry for my mistake for wording in my post, replace instances of "sidechain" with SSC in the final part, I understand that obviously compressor units must have a sidechain detection. 

Hoping someone saved stitch-o's old diagram, his has been lost to the internet and I'd really just like to figure out the DPDT wiring, not sure if the crude diagram in that link provided halfway down the page does the justice. 

Happy holidays all.

I just build one like this and I used the diagram here on reply #4
http://groupdiy.com/index.php?topic=36643.0
I ended up using the jakob bypass method not the SSC method and it works great. Having some weirdness with the side chain values/compression but that is another topic and you can read about it on reply #401 here...
http://groupdiy.com/index.php?topic=16113.msg742186#msg742186

Edit: I did leave the 100r and 56k resistors. That diagram looks like it says to replace them with 100k but I didn't do that cause I thought that wasn't nesessary. Maybe I'm wrong about that but it worked out fine.

 

[finbase]

Greetings... Sorry, this will be a long post!

OK, here's my embarrassing story on the whole, and it's moral lesson is: NEVER TRY TROUBLESHOOTING TIRED!

I finally finished my GSSL kit from Gustav, with added SSC-board. Everything went well, and although it was already pretty late, I turned the unit on and made a test drive. Everything worked and sounded OK, but it seemed, that the left channel  was a bit louder than the right one. I'd have stopped there  and had a good sleep. But instead I started to solve the problem.

So after some researching on the help thread I decided to try changing the IC's in the input and output section. I took some chips from my own supplies, and since I was pretty tired, I put a NE5532P chip in the input section by accident. I turned the unit on, and passed some audio: now the left channel was heavily distorting, and after a few seconds the 10 ohm resistors in the PSU section started smoking and burned off...

I spotted my failure, and put right IC's on the right places, and replaced the damaged resistors. I turned on the unit again this morning, after double-checking everything with the fresh brain, but the resistors burned off again...

I noticed that Weiss have had the same problem, and if I understood right, the reason for his pains was a damaged IC somewhere...

The long story short: everything worked quite OK----wrong ICs----10ohm PSU resistors gone-----right ICs-----10ohm PSU resistors still gone.

So my questions:
-How I can test my IC's with just a DMM? (If the problem is due to the ICs after all. But the problem occurred after changing them, so I suppose that the answer lies there somewhere...)
-I'm currently searching the short circuits.. I'll post the results on the IC pins soon. Any other possibilities where to chase one?
-Any other suggestions, what may have caused the problem?

Thanks,
finbase

 

[gyraf]

IC's that has been put in wrong sockets (or oriented wrong) with power on, should be considered dead.

There's no way to "multimeter" IC functionality. Try in-circuit.

Jakob E.

 

[finbase]

IC's that has been put in wrong sockets (or oriented wrong) with power on, should be considered dead.

There's no way to "multimeter" IC functionality. Try in-circuit.

Jakob E.

Thanks Jakob!

So your suggestion is to replace the ICs, and try out again?

BTW, if there's any help, I measured the resistances from the IC sockets against the ground... Here's the values, does everything sound OK?

Left ch in NE5534 (Socket)
1. O.L
2. O.L (starts from around 3M, the resistance grows rather slowly beyond 20M)
3. 22K
4. 5K27
5. O.L
6. O.L (starts from around 16M, but the resistance grows rather quickly beyond 20M)
7.44K9
8. O.L

Right ch in NE5534 (Socket)

1. O.L
2. O.L (starts from around 3M, the resistance grows rather slowly beyond 20M)
3. 22K
4. 5K26 (an slowly increasing)
5. O.L
6. O.L (starts from around 16M, but the resistance grows rather quickly beyond 20M)
7. 44K9
8. O.L

Left ch out NE5532P
1. starts at 3M, starts increasing rather slowly)
2. starts at 6M4, increases slowly
3. 466R
4. Starts at O.L, and then decreases, goes back to O.L etc.
5. 468R
6. Starts at 6M7, increases slowly
7. Starts at 6M8, increases slowly
8. 5K35 (decreases very slowly)

Right ch out NE5532P
1. starts at 3M, starts increasing rather slowly)
2. starts at 3M, starts increasing rather slowly)
3. 467R
4. Starts at O.L, and then decreases, goes back to O.L etc.
5. 465R
6. starts at 3M, starts increasing rather slowly)
7. starts at 3M, starts increasing rather slowly)
8. 5K35 (decreases very slowly)

Thanks,
finbase

 

[gyraf]

Sorry, these figures can't be used diagnostically.

Jakob E.

 

[finbase]

Sorry, these figures can't be used diagnostically.

Jakob E.

I was actually in contact with Weiss, and decided to swap all my input and output ICs and bada bing bada boom: the unit works perfectly right now!

Best regards,
finbase

 

[finbase]

After a few burned resistors and damaged ICs both GSSLs are finally alive! And they sound GORGEOUS!! Punchy and transparent, just like the SSL bus comp is supposed to sound!

The red one will be eventually treated with the Expat audio's Cavendish modification, but it might take some time before I'm able to actually start the modding, there's a second child arriving! The due date was actually today!! ;D

BTW, anyone interested: try out the Hairball Fet 500 comps! They sound absolutely brilliant! Warmly recommended!

Thanks everyone who shared their expertise during this project!!

Thanks,
finbase