GSSL HELP THREAD!!!

[geetar_king]

Anyone else had to tweak the voltages at the opamps?

I'm using the exact semiconductors outlined in Greg's BOM (http://members.cox.net/capstanrecording/SSLCloneParts.pdf).

 

[guavatone]

The voltage should be referenced to the GSSL schematic, not the datasheet of opamps.

 

[wmtunate]

[quote author="geetar_king"]This is what I'm using for TL074: http://www.fairchildsemi.com/ds/LF/LF347.pdf

On Pin 4 I get +12.21 Vdc which the data shows as Vcc.
+12.14Vdc on pin 11 which the data sheet shows as Vee

Data sheet says supply voltage (Vcc) should be 18V is that the problem you think? or should i be checking a different pin



----

Similar thing for TL072.
http://www.fairchildsemi.com/ds/LF/LF353.pdf

I have about +12.21 Vdc on Pin 8 which is Vcc. And about +12.38 on pin 4.

The Gyraf schematic shows +12V /-12V supply to TL074, and +12V/-12V to TL072.[/quote]

If you're getting positive voltages at your Vee pins, I suspect that your negative voltage regulator is incorrect. Check the voltage right at the output pin of the 79L12, and also make sure that it's actually a 79L12 fitted, and not a 78L12 instead.

 

[geetar_king]

Good catch, should be negative. I just tried getting readings off the regs and they are all over the place. I'll pop some new regs in and check.

The negative voltage reg in Gregs Bill of materials was the only one I couldnt find, and had to get one from mouser.

Greg's lists AN79L12-ND (digi-key): http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=AN79L12-ND

Digi-key didn't have it in stock so I used this one from mouser: http://www.nteinc.com/specs/1900to1999/pdf/nte1903.pdf

maybe I picked a bad one? i dunno, seemed okay in the specs

Anyone know a digi-key # that works for sure to replace AN79L12-ND, the 79L12?

 

[SIXTYNINER]

....Can be the soldered pin?
6tnr

 

[Chrome Heart]

"Anyone know a digi-key # that works for sure to replace AN79L12-ND, the 79L12? "
This is what I used. Same specs.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=LM320LZ-12-ND

 

[guavatone]

the"nd" is just a digikey part reference. just search 79L12.

The NTE part should be fine albeit expensive.

What do you mean by "all over the place"?

-I would also check for solder globs touching the wrong places. The pads are pretty tight on that PCB.

I had one solder point that creeped over the solder mask and was messing up everything.

 

[Dr nEon]

Hey guys..

Can anyone help me out with a ratio problem...

I've just been measuring the ratios on a nu build gssl(w/turbo) , and finding that they were very low. I posted about this first on the turbo help thread,thinking it was,perhaps, a turbo issue , or a fault somewhere..

Anyway 10:1 was actually about 3.9:1 , 4:1 was like nearer 2:1 etc.. VERY low!

All of measuring was done with the attack control at slowest setting 30mS ( which is where I mostly set it when over the mix buss)

After a day or so of looking for a fault , and not finding anything conclusive , in desperation I just tried testing at other att/rel settings to see if that lead to anything..

Well it did because I found that release time made no difference , but the attack time , even on a steady-state sine tone , influences the amount of GR by around 2.5 dB. (difference between fastest/slowest)
Fair enough , but I'd always imagined that would be a static offset .

Not so , it appears , because when I repeated my ratio measuring procedure , with the attack control set to fastest , the ratios read near perfect values .


So , after this long-winded pre amble , my question is :

Where should the attack control be set , when checking ratio values?


We've a lot of discussion on the forum about changing the 127k resistor to suit your chosen vca , etc ,but I haven't seen anyone comment on the importance of attack time in all of this.
I think I even read one post that said it didn't matter...but i think it does.


I wonder where the actual 10:1 is on an original ssl , at which attack time...

(After 20 odd years mixin on them , I'd like to put my ratios close to what I'm used to..)


Any thoughts? ..

Cheers!

nEon.

 

[feza]

Hey,

Well after reading a lot of the GSSL I have learned many things. I want it to be a crazy GSSL but I do not know if it is going to work. This is quite something and what I want is this : The GSSL with the Turbo mod, Super Sidechain and Igor's bypass boards fitted in Purusha's Oxford case. :grin:

I already have the Turbo mod, Oxford case and the bypass boards are on the way. But the Super Sidechain has to be bought and sent a PM to that respective owner, which is selling one stuffed.

My question to you Guru's out there ; is this going to work? I don't want the relais on the sidechain to be functional. The bypass board of Igor must be doing the relais bypass. The Turbo mod has to be "always on" which is possible and is even documented in the Turbo's manual. Still have to read again the manual but my build also uses the boards of Igor.

I'm thinking it is possible and reading a lot about the wiring as well. But can somebody shed some light about this configuration whenever the relais of the sidechain can be unused or other things that comes in mind?

Thanks for the reply! :thumb:

 

[Dr nEon]

I think it will work if you have bought TWO supersidechain boards..

I am busy putting together a gssl with turbo and two sidechain boards .

My guess is , if you don't want/need to use the relay on the supersidechain then leave it unstuffed...it's very easy to see on those boards where the relay switching part of the circuit is...nice simple boards to understand..

And then just use Igors relay as you want....I did this too,but with my own relay card

cheers

nEon

 

[feza]

Thanks for the reply!

You're right. I need two boards! Completely forgot about that. Well. Some future purchase hopefully. :wink:

 

[Dr nEon]

You're most welcome,Feza..!

BTW: I'm still looking for answers to my post above , about ratio measurement..

When you're calculating which value resistor you need for correct ratios , are you doing it with ATTACK set to fastest or slowest??

cheers

nEon

 

[feza]

Sorry man. Can't help you there.

I'm still in the progress of collecting all the parts. Eventually I can help you and other members. I've read a lot of topics and made notes. But haven't seen correct way of measurement what you are asking. If something comes up I will let you know.

Good luck!


*Searched my notes again and saw this that might help you :

"one has all 2151's & one has all 2180's less trimmer, 68r, 10k & 47r in side chain. I did the 100k to 120k Ratio mod on the one with 2180's & changed the meter resistor to 3k and everything is perfect on that one.
The Ratio mod didn't affect the CV at ALL!!! but did fix the ratio's. so all is well."

*About the 3K resistor I just do not know which meter it has been, 1K and 2K are quite common.

 

[Dr nEon]

Thanks Feza...yeah it's a question that I'd love to hear input from Jakob,SSLtech ..any of the big guns around here,or guys with an orig ssl to hand.

The 120k resistor with 2180la will only result in the correct ratios at the FASTEST attack time setting...which is where I'm assuming everyone sets it when performing their measurements.(I'd like confirmation of this)
However , change the attack to slowest setting 30mS and repeat the procedure , and suddenly your ratios are down..i.e. 10:1 ratio is really around 4:1 .

In real world situations I use 30mS or 10mS more often that .1mS , and so I'm really running with ratios a lot lower than nominal,if I use 120k..

However , I can put a 100k resistor back in , and have ratios perfect for 30mS attack, but then they will be a little higher at fast attack settings..

So Which is the correct option?..this is my question.

Is there a standard attack time to base ratio measurements on?

Looking forward to receiving enlightenment on this one!

Cheers

nEon

 

[feza]

[quote author="Dr nEon"]
So Which is the correct option?..this is my question.

Is there a standard attack time to base ratio measurements on?[/quote]

Man! I remembered a bit of your question and started thinking. :grin:

Here you go : http://www.groupdiy.com/index.php?topic=944

Good luck!

 

[Dr nEon]

Cheers again feza ,

I saved off all those pages a few years back ...and I've read them countless times , and NOWHERE is this issue discussed in that whole thread!!! :shock:

So you can see why i'm so keen to get an answer to this ...someone MUST have the answer!

But appreciate your input,man!

Cheers

nEon

 

[Barbera Media]

Well, I have both GSSL's in their chassis and fired them up for the first time and one worked perfectly, nothing wrong, no smoke and sounds great! The other one has a very interesting problem. I'll try to describe it as best I can.

When the unit is connected normally, the right channel is about 2 to 3 times louder than the left channel. To make things even weirder, as I disconnected the right input, the left channel volume shot way up and with only one channel connected, no compression happens. I then plugged the right channel back in and it went back to the way it was. When I unplug the left channel, the same thing happens to the right channel with no compression. Also with the unit connected normally the compression is happening but is very very transparent, as in the threshold control sounds more like a volume control if that makes any sense.

I'm completely lost about what could be wrong or what to do and couldn't find anything when searching that could point me in the right direction. Any ideas? Thanks.

 

[mitsos]

I was just starting to go through this thread... I had downloaded the html someone had uploaded which had this whole thread on one page, but it only went to page 147, so I added the rest to help me search. If anyone wants it, I put it on rapidshare as a .rar file (you need WinRAR or unRarX to unpack it, both available free or shareware I think). It goes through this page, but since I used the old file (instead of resaving the first 147 pages) a couple of posts from page 147 are there twice.

http://rapidshare.com/files/157001552/GSSL_pg186.rar

 

[somsay]

thank you guavatone for all your help!

my gssl is alive! but the left channel is louder than the right.

i double checked my wiring, any suggestions on how to balance my left and right outputs?

thanks allot

 

[Barbera Media]

Somsay, sounds like you have the same problem I have, although my right channel is louder. Does your unit compress? If so is it very "transparent" as in the threshold control sounds more like a volume control rather than adjusting the compression? Doesn't look like anyone has an idea or no one has checked this thread. Anyone have any ideas???