GSSL HELP THREAD!!!

[gyraf]

Yes, the voltage and current ratings for the diodes are (as always) minimum ratings. So are voltages for capacitors.

Jakob E.

 

[rotation]

Hi!
I'm soldering last components. I can't find the 78l12 and 79l12. Guy said i could use also 7812 and 7912 instate. Is this correct?

 

[Greg]

They have different footprint than the "L"... so you won't be able to fit them in the board. But I guess they'll work. I'd keep looking for the 78L12 and 79L12.

 

[rotation]

Aha, so i will find 78l..I don't want to change and experiment too much. Btw, i'm "buying" parts from company which is selling for Farnell, and every time i buy something they give me like 30-40% of wrong components :evil: This is really anoying..I think i have to buy directly from Farnell or somewhere else.
Miha

 

[bluezplaya]

I have been trying to wrap up my SSL project for a couple of days now and am making progress but still need some work. The unit used to just pass audio and increase a little bit of volume at the very last turn of the makeup gain. After moving the PCB around and wiggling wires during audio, I noticed jumps in the volume. I was using Cat5 wire and wasn't happy with the thickness and it being stranded wire.

I rewired the connection of the boards with rainbow cable (solid, 22 awg) and was pleased to see the power LED come on (previously did not) as well as a smooth, gradual gain increase with the makeup gain pot (as it should be). Now the meter does not work, as where it previously did. The meter never worked like it was supposed to, only moped around.

Voltage regs are warm to the touch and don't appear to be overheated.

I still to this day have not had any compression whatsoever. The bypass switch is wired according to the parts layout on Gyraf. All jumpers accounted for. All component values looking good. I am beginning to wonder if I have a bad VCA or opamp.

Any suggestions?

Thanks,
Adam
:sam:

 

[bluezplaya]

Okay, I have swapped the 3 VCA's around with each other and they seem to be fine. However, I think I remember having the TL074 backwards at the beginning of this project and switching it to its right place. Did my TL074 burn up on the first power up? Could this be my problem? If so, I have another one on order from Mouser.

Also, both channels pass audio fine at the same volume but the right side has no lows. It is all highs and high mids. Any suggestions?

Adam
:sam:

 

[gyraf]

..if you reverse a TL074 and poser up, there's a 99% chance that it's dead..

 

[bluezplaya]

So the unit will still pass audio but not compress? I take it, with a blown TL074 it just isn't getting signal to the sidechain VCA?

Adam
:sam:

 

[gyraf]

yes

 

[flight]

Hello to all
I wanna know if i can use OPA 2604AP instead of NE5532
and use OPA604AP instead of NE5534.

Maybe its not a good question but if anyone can aswer me why i cant do that , it ll be very appreciated
thanks

 

[bluezplaya]

Okay I swapped out the TL074 twice with two from my green pre's (I had one on order from Mouser) and am getting the same results. Could the 5532's or 5534's be bad?

Adam
:sam:

 

[tommypiper]

OK, I think my compressor is working now. :grin: (The previous owner had all the switches wired backwards, among other things.)


Now I'm trying to adjust operating controls and do some testing.

[quote author="gyraf"]The whole ratio compensation for That218x thing is an entirely different matter, nothing to do with metering. it involves a change of a 100K resistor to a 127K resistor - look at the updated page at Gyraf - this is the ONLY 127K resistor in the circuit. [/quote]

I could not find this information on the Gyraf site. He appears to have changed it. Please explain what this is.

[quote author="gyraf"]If 2150, then use the old 100K resistor.[/quote]

What does this 100k resistor adjust? I researched this thread and looked at the Gyraf site and could not find the answer. It is not on the latest artwork or PDF either.

Is this resistor threshold range, or threshold sensitivity? Does higher value = wider range sensitivity? Or waht? If so, then why would I change to 100k? I'm confused. Help!

My threshold sensitivity is too narrow and too coarse. I am using 2150 and 127k resistor at the moment. If I change to 100k resistor won't this narrow the threshold range? :?

Thanks for helping.

 

[Luigi]

I found the problem!!
After carefully looking the conponents closely, there was a pcb part that was actually defected. One part of the pcb was a bit cut, so I had to sand off the enamel and re-sauder the part, then, boom, everything worked!!
It sounds great!!!!
Im sorry for being unpatient, but I guess I just wanted to hear the sound!!
I just learned how to be patient!! hehe
Thanks guys and sorry for asking stupid questions!

Now, let me start the second one! hahaha

 

[tommypiper]

Still confused. Jacob? Anyone?

 

[gyraf]

info is all around here. long story to explain. search.

 

[tommypiper]

OK... Well, I swapped the 127k resistor for 100k per your instructions. Just want to confirm, this is the resistor to the immediate right of the TLO74? I don't notice any difference. (I believe it's ratio? I've asked this question before above. It needn't be a "long story," one word could suffice. :grin: )

DISTORTION:
I am still getting distortion on fast release and fast attack settings (with program material, even with very mild GR). The low end diminishes and the top sounds tinny and distorted. (Please don't tell me to read this thread again, I have spent days reading it and taking notes. My situation is unique AFAIK, see below.)

Is it normal to get such distortion on the fast settings? I imagine not, then where should I look? This would be suggestive of audio VCA ovorloading? Then why on fast release? Even with mild threshold and GR settings it is evident. (Others have reported distortion, but only on higher GR.) Everything appears normal and working fine, otherwise. Therefore my question.

 

[tommypiper]

Any help would be appreciated.

Purusha had distortion with the standard resistors (although possibly different than my distortion, but I thought it may be related, as it's all I've been able to find in the threads that compared to my problem.) So I tried the mods he and others used in the 2181 calibration discussion and now I am only getting buzz, no audio. The meter is pegged. Getting only buzz. :sad:

I've double checked everything.

Any help would be appreciated.

 

[Barforama]

Hi NG

We have just finished a weekend SSL-building-get-together. A total of 6 clones were constructed. Two of the units was working right away. We were able to trouble shoot on two of the others and make them work properly. Leftover are two units. The one I have here is semi-working. One channel is working just fine, the other is outputting 5-6dB less than supposed.
My first thoughts told me that the error would be in the output or VCA-circuit of the less hot channel, but I cannot find any errors in those areas. I have checked solderings extensively, orientation of OP-amps and condensors and finally I have checked all resistors in the same areas.
I have read most of this Meta-thread and it is frequently suggested that there might be a short around pins 1-2-3 in the 5532 of the faulty channel, but there's not. Any suggestions?

 

[dustbro]

I'm ordering the parts for this Gssl... Digikey and mouser are both out of the 50K Trim pot. Would this one be ok to use?
http://www.allelectronics.com/cgi-bin/item/TPT-50K/470100/50K_SINGLE_TURN_TRIM_POT_.html

Also, the 1N4148 is discontinued (1n4148msct-nd on the partlist)
http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=353&M=1N4148
Can I use this one instead?
http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=353&M=1N4148-TP
The only difference is the one that is available is Lead free and is Lead Free and RoHS Compliant... dont know what either of them mean


Thanks

 

[desol]

Hi NG

The one I have here is semi-working. One channel is working just fine, the other is outputting 5-6dB less than supposed.
quote]

I think i had this problem..turned out to be a ground issue. lol :roll: