GSSL HELP THREAD!!!

[schrobbelbop]

Hi all!
I finished my first GSSL some years ago and now I´m building three more. My first of the "new" ones is working like a charm but my second has a problem.
It passes audio and the makeup gain is working but there is no compression and the meter is dead. I have tried searching this forum but can not find an answer. It has probably been answered in this thread but it is 200-something pages.... :-\

Can anybody help me in the right direction?
I have swapped all IC´s. Out-ruled the controlboard. (works with the other unit). Searched for solderbridges around sidechain and TL074.

The compressors are built with That 2180´s. The first (working) one has panasonic FM caps and the second one Nichicons. The 3,9K´s resistors besides the VCA´s are changed to slightly different values on the two compressors, 4,8 - 5,0K. Other than that they "should" be identical.

Anyone who has that simple explanation? 

Henrik

Seems to me an Issue with your by-pass switching.

 

[Bonke]

By the way, I did find the soloution for another problem that might be helpful for someone.
I had distortion on the autorelease. It was my lorlinswitch that was wrongfully programmed. It was five steps alright, but the wrong steps apparently.
I just removed the "stop" on the lorlinswitch and turned it all the way counterclockwise and set it to five steps. Before I had it set for five steps starting on another step. Pretty wierd that it was possible.
Anyho, hope that can help someone out there.

Henrik

 

[Bonke]

[/quote]

Seems to me an Issue with your by-pass switching.
[/quote]

Hi, thanks for the reply.
Don´t think so, cause the controlboard worked with my other compressor. But I will doublecheck my bypass-switch.

Henrik

 

[Jazzboms]

Hi

Seems like I have resolved my problems.
I error seeked over and over, but could not find any wrong, so I decided to build another one, checking every component, every soilder, continuity,+++, using the same control board. Got the same result. My control board was fine, but not my VCAs. It seem like out of my 6 VCAs, only 2 did work. The 2 in the audio chain was working so I didnt think about checking the other ones if they passed audio in the audio chain. When I tried, they all was without sound, or distorted. I think I have blewn them all on my first try. (this was my 2nd, and 3rd)
I just got 3 more VCAs, and then everything worked.
Anyway Im happy, now I have 2 working units, and have gained A LOT of experience.
Now the metalworks starts.

Thanks for the help.

 

[Bonke]

Hi all!
I finished my first GSSL some years ago and now I´m building three more. My first of the "new" ones is working like a charm but my second has a problem.
It passes audio and the makeup gain is working but there is no compression and the meter is dead. I have tried searching this forum but can not find an answer. It has probably been answered in this thread but it is 200-something pages.... :-\

Can anybody help me in the right direction?
I have swapped all IC´s. Out-ruled the controlboard. (works with the other unit). Searched for solderbridges around sidechain and TL074.

The compressors are built with That 2180´s. The first (working) one has panasonic FM caps and the second one Nichicons. The 3,9K´s resistors besides the VCA´s are changed to slightly different values on the two compressors, 4,8 - 5,0K. Other than that they "should" be identical.

Anyone who has that simple explanation? 

Henrik

Seems to me an Issue with your by-pass switching.

It is defenetly not the bypass switch. I plugged in the controlboard to my other compressor and it works perfectly.
I have narrowed it down to that there is something wrong with the "motherboard".
I changed it to another stuffed board I have and then the compressor worked.
So, where should I start looking on the motherboard?
It is not the IC´s and not the VCA´s, I have tried them in the oter compressor and they work.
As I mentioned before the compressor is passing audio and the makeup gain is working but there is no compression. Threshold, ratio, attck and release are dead.

Henrik

 

[ruckus328]

Hey guys, quick question.  What size chassis do you recommend for a GSSL?  I was planning on getting a pre-made 19" rack enclosure from par-metal unless anybody has any other source recommendations, however I'm unsure about which depth to go with.  Was going to get an 19" x 1.75" x 8" deep enclosure but not sure if that's to small.  11" deep is the next size up but obviously don't want to go that big if I don't have to.  Thanks!

 

[Autophase]

Hey guys, could anyone help me out with my cross talk issue, the quesiton is on the previous page.
Thanks

 

[j.frad]

By the way, I did find the soloution for another problem that might be helpful for someone.
I had distortion on the autorelease. It was my lorlinswitch that was wrongfully programmed. It was five steps alright, but the wrong steps apparently.
I just removed the "stop" on the lorlinswitch and turned it all the way counterclockwise and set it to five steps. Before I had it set for five steps starting on another step. Pretty wierd that it was possible.
Anyho, hope that can help someone out there.

Henrik

I let the release switch go to it's 6th position, it lifts the sidechain caps and resistors and freaks out the sidechain, sometimes the resulting distortion can be useful.

I'm having a really strange problem on my upcoming gssl: The right channel has a gain of about 6dB, has anybody ever had that? both channels recieve signal from both hot and cold point on the xlrs, so i think it's not a balancing issue in the wiring. I've been struggling with this machine and i'm almost there!

 

[johnmellor]

thanks again regular john.
here we go a couple of questions... (just about there now)

is it worth using alice driver boards for a sifam 34a meter, or should I just wire it straight to pcb? I've seen an expat audio video mounting connecting the driver board up http://www.youtube.com/watch?v=ZUhkuxa6Ke8, however the driver board i've got has 8pins on the output.

Also since I was unable to find the TL074  quad op required, I have chosen an analogue devices 713jn ?

 

[noisecontrol]

Hey guys, nearly finished my first GSSL build but, my threshold control doesn't work. Everything else seems to be fine. If I adjust the input externally I can see the compression vary on the meter, attack and release and make up all work fine.

According to other posts this is what I have checked:

Pin 1 of the TL072 varies between 0-3V when I adjust the threshold. Pin 7 does not, it seems to be close to 0V always. I think this is my problem but I have checked all resistor values and caps in the vicinity and they are all correct. If I measure the resistance at pin 7 it is about 80K to ground.
I have checked for solder shorts etc and my soldering looks fine with a magnifying glass. I am now stuck as I have no idea what else I can check.

It seems that user bluezplaya had a very similar problem in this thread but no further posts were made if he corrected the issue.
Cheers
Reuben
EDIT: Also I have noticed that when measuring the DC voltages, I require the GSSL audio input to be connected to the output of my audio interface otherwise the voltages all seem to vary between 0 and -0.3V. Soon as I plug it in all the voltages seem normal?

 

[regularjohn]

EDIT: Also I have noticed that when measuring the DC voltages, I require the GSSL audio input to be connected to the output of my audio interface otherwise the voltages all seem to vary between 0 and -0.3V. Soon as I plug it in all the voltages seem normal?

Sounds like you have a grounding problem.  If the voltages can't drain via ground, you won't have a 0V reference for checking them.  I would recommend checking that your audio ground is making it to the chassis, and that the chassis is also connected to AC ground.

By plugging into another piece of gear, you're allowing the ground a drain path via the other piece of gear.  Improper grounding can do funny things.

 

[champ72]

hi

thisi is my problem:

before yestreday it work good...

but now it doesn't compress anything,meter not work,but makeup ok

 

[noisecontrol]

Sounds like you have a grounding problem.  If the voltages can't drain via ground, you won't have a 0V reference for checking them.  I would recommend checking that your audio ground is making it to the chassis, and that the chassis is also connected to AC ground.

By plugging into another piece of gear, you're allowing the ground a drain path via the other piece of gear.  Improper grounding can do funny things.

Thanks, yeah I was just testing it temporarily so I didn't have the earth from the audio input grounded to the chassis. However, the problem still exists that the threshold control has no effect. Any ideas on how to chase this one down?

Cheers

 

[Crusty2]

Hey guys, nearly finished my first GSSL build but, my threshold control doesn't work. Everything else seems to be fine. If I adjust the input externally I can see the compression vary on the meter, attack and release and make up all work fine.

According to other posts this is what I have checked:

Pin 1 of the TL072 varies between 0-3V when I adjust the threshold. Pin 7 does not, it seems to be close to 0V always. I think this is my problem but I have checked all resistor values and caps in the vicinity and they are all correct. If I measure the resistance at pin 7 it is about 80K to ground.
I have checked for solder shorts etc and my soldering looks fine with a magnifying glass. I am now stuck as I have no idea what else I can check.

It seems that user bluezplaya had a very similar problem in this thread but no further posts were made if he corrected the issue.
Cheers
Reuben
EDIT: Also I have noticed that when measuring the DC voltages, I require the GSSL audio input to be connected to the output of my audio interface otherwise the voltages all seem to vary between 0 and -0.3V. Soon as I plug it in all the voltages seem normal?

Referring to this schematic: http://gyraf.dk/gy_pd/ssl/ssl_sch.gif

MAKEUP control should vary pin 7 of TL072 from 0V to -2V. THRESHOLD will only affect pin 7 if audio is going through the unit.

Check pin 3 of SIDECHAIN VCA to make sure that signal from threshold amp output (TL072, pin 1) is getting there.

 

[champ72]

i check voltage on sidechain "that" positive it's about 12v but neg is -8,5v,then i check 79l12 out ,and 'its ok.

but my gssl not compress

 

[noisecontrol]

Referring to this schematic: http://gyraf.dk/gy_pd/ssl/ssl_sch.gif

MAKEUP control should vary pin 7 of TL072 from 0V to -2V. THRESHOLD will only affect pin 7 if audio is going through the unit.

Check pin 3 of SIDECHAIN VCA to make sure that signal from threshold amp output (TL072, pin 1) is getting there.

Thanks!! This helped me to solve the problem of the threshold control not working. I followed the signal to pin 3 of the sidechain VCA and guess what the problem was?... My soldering after all, it wasn't quite getting a good contact on pin 3. So I am glad to say that it is now all working well. Cheers guys.

 

[MikeFFG]

First post!  I bet this has been asked before, but I wouldn't even know how to begin searching for it.  On my Gssl boards from Gustav, on the smaller board with the attack, release, etc...just to the right of the release part, next to the 750k resistor, there is a jumper wire.  That I get...but then there are two lines coming from ends of the jumper wires that don't seem to point to anything and form sort of a triangle.  Can anyone tell me why this is or what it means?  Thanks!

 

[ChrioN]

Look at the pdf documentation at gyrafs place. Its all there.

 

[MikeFFG]

Look at the pdf documentation at gyrafs place. Its all there.

my bad I somehow downloaded just the schematic without the rest of the documentation...thx

 

[ruckus328]

Hey guys.  OK, I have 2 questions:

1) Can someone give me a straight answer here - When using a THAT2181 should I use the resistor values Gyraf has on his layout/schematic or should I use Matt's values?:

http://diy.fischerworks.com/gssl_vca.shtml

What about the two 15K Resistors next to the VCA's? - should they be changed to 27K?

2) I have Gyraf's board Rev 7 - There is a .1uF Cap on the sidechain VCA between pins 6 & 7.  It is not on his current assembly drawing & not on his schematic.
Should this be installed?  I would think yes, since it appears to be simply a bypass cap.