GSSL HELP THREAD!!!

[CJ]

Hey Stich , you owe us 149.50 consultation, new state law for 2008, and BTW. lets talk gift cards, 483 million for home depot, only 9 in 10 gift cards get used, huge racket, biollions nation wide, but now, in Cal EW For Ni A, we get b10 dollars change bak!

7 posts = Twist Turne, give me what I want, I will give4 nothing back, I only post when I need something, beciase I played with Sonny Terry, so my chi town shit diont stink and what w3as the question for or green grass roots forum?

I almost got into a fight with an illegal at the Bike Connection in Palo Alto, they suck, never go there, I walk in wityh a gift card woth 65 dollah and ask for 10 back , he says "Go shove it Wedo! (m spanish derog for white boy)
so I says, get on google and search!
he search, then sya OK!

I'm a veg, Danny.

 

[gyraf]

:shock: :razz:

 

[Ptownkid]

CJ, your posts both confuse and entertain.

cheers

 

[stitch-o]

[quote author="CJ"]Hey Stich , you owe us 149.50 consultation, new state law for 2008, and BTW. lets talk gift cards, 483 million for home depot, only 9 in 10 gift cards get used, huge racket, biollions nation wide, but now, in Cal EW For Ni A, we get b10 dollars change bak!

7 posts = Twist Turne, give me what I want, I will give4 nothing back, I only post when I need something, beciase I played with Sonny Terry, so my chi town shit diont stink and what w3as the question for or green grass roots forum?

I almost got into a fight with an illegal at the Bike Connection in Palo Alto, they suck, never go there, I walk in wityh a gift card woth 65 dollah and ask for 10 back , he says "Go shove it Wedo! (m spanish derog for white boy)
so I says, get on google and search!
he search, then sya OK!

I'm a veg, Danny.[/quote]

we all gotta start somewhere, cracka.

Besides, on electronics, I don't know enough yet to contribute anything informative or educational. I'll learn project at a time and ask questions. And, god forbid, I have something to contribute to help someone else, I will.
If you think I'm here to just take, don't say a word, and I'll be on my merry way. But it all comes all around, don't it?
I know it...

thanks again, Jakob.

cheers!

 

[Bluzzi]

stitch-o, I don't blame your reaction on CJ, you haven't been around here long enough to know that he never means any harm.

With some of us you have to read between the lines, with CJ you have to read between the letters! :grin:

The scary part is I'm starting to actually understand what he writes! :wink:

jim

 

[scottCFP]

Hi all!

Still troubleshooting my SSL build. Thanks for the bits of help provided so far!

I have a very NOOB question: When testing voltages across OpAmp pins, which pins do I place my red/black ends of my meter...embarrassing, but ya....getting positive and negative values.

Can someone verify:
5532s: 30V across pins 4 and 8
5543s: 30V across pins 4 and 7
TL074: 25V across pins 4 and 11
TL072: 24V across pins 4 and 8


Last note: I don't have a scope, so I'm tracing the audio from input to output. As of right now, I get audio up to the 27k res into the VCA, but not through the resistors. I tested the 5534s, and they work. I took one out (testing 1 channel at a time) and left the VCA in and got audio through, very distorted, controls do nothing. Any thoughts on this?

Thanks for any help!

Scott

 

[scottCFP]

Ok,

I found the answer to my NOOB question as posted above...

I also found that I have -24V across pins 4 and 11 on TL074, where it should be +24V? Can anyone shed some light on this? I'm digging!

Thanks!

Scott

 

[Harpo]

Your -24V is OK. You just flipped the red/black wire for measurment.
Easiest way to not confuse yourself is taking the black wire for measuring to gnd and probing each voltage seperate with the red wire, reading -12V at pin 11 and +12V at pin 4.

 

[scottCFP]

Ok,

So I took out (on the channel I was testing) the VCA and jumpered between p1 and p8 and audio passed through. Controls did nothing, shouldn't the input/output do something? Putting the VCA back in yields no audio, buzz or anything. Bad VCA? Short near VCA? Does this spark any ideas that might help pinpoint the problem?

Still digging.

Scott

 

[Stagefright13]

Well just a thought on my end but the GSSL board makes it very easy to make a solder bridge if not careful. Examine the underside against the schematic. Or solderwick every location that seems too close or bridged.

And CJ always makes perfect sense to me! :?: :idea: :roll:

 

[scottCFP]

yes.

No solder bridges :grin: , just missing some of the modifications buried in the middle of the thread for the THAT1281LA circuit. Just needed to pull a couple parts near the VCAs (sidechain AND audio, found that out this morning)

UNFORTUNATELY, snapped a flippin' leg off of a VCA while taking it out, so I only got 1 channel of bliss, but much radness...

Thanks for the great project. I'm sure I'm not quite out of the woods though!!

scott

 

[scottCFP]

Got my VCA, both channels do their job. Just need to find my hum/buzz source and I'm done!

Thanks all!

scott

 

[Dr nEon]

Hi all!

I have a question regarding the large 1000uF caps in the gssl psu.

Would a 50volt rating be ok in that position?

I have a stock of those low-esr pink dubilier caps from Rapid electronics which are 1000u 50v , and are perfect height-wise for fitting into 1u case.

The layout and schematics all list 35v , but the various parts lists all say 63v.

It would be nice to know if 50v is allowable , as most people are building into 1u cases .

Cheers

nEon.

 

[Harpo]

Hi nEon,

I have a question regarding the large 1000uF caps in the gssl psu.

Would a 50volt rating be ok in that position?

short answer, yes.
Depending on your transformers secondary (2x 15V or 30V ct || 2x 18V or 36V ct) and allowing 10% line overvoltage your caps will see 24V DC || 28V DC max. after the rectifier, ignoring the 1.4 V diode drop.
( V DC = V AC x 1.1 overvoltage x 1.414 rectified - 2x0.7V diode drop )
Anything above this min.rating will be OK.
-Harpo

 

[Dr nEon]

Harpo...Thanks for the thumbs up and formulae on that one !

I'll go for the 1000u 50v then..it'll be FCs or the dubiliers....on that note, do you think those low esr type caps are ok to use in such a standard ( ie non switched mode) power supply?

Thanks again!

nEon.

 

[udenjoe]

I got mine put together. I used the LED meter. I wired the plus minus wrong and blew the 10rs on the LED board. Replaced them.

Now it powers up just fine, but I get no sound coming through. The power LED from the small control board lights up. I was running a record through it. I could hear the sound coming through a short second while powering it on but that's it. I don't know where to start troubleshooting.

I'm pretty sure the power side is good. It warms up, like I said the LED lights up. No smoke.

I'm not sure if I have a messed up chip somewhere. I used that one guy's (Mark? I've changed comps and don't have the link anymore) colored table to calibrate for the 2180LBs I have in there. I didn't do any mods. I figure I should at least hear some sound coming through.

 

[crisotop]

strange meter behaviour:

I'm using this cheap vu http://at.farnell.com/jsp/Elektrote...splayProduct.jsp?sku=143509&_requestid=198494 and wanted to get a 10dB meter scale, so I used a 1k resistor (strapped a 330 Ohm resistor across the vu, since it's an 100uA) - but oddly enough the meter represented a 20dB scale with the 1k resistor? I swapped it for a 2k and now it's working as it should? Is there a simple explanation for this, that I don't get?

Thanks in advance
Christoph[/quote]

 

[Harpo]

[quote author="udenjoe"]Now it powers up just fine, but I get no sound coming through. The power LED from the small control board lights up. ...I'm pretty sure the power side is good. It warms up, like I said the LED lights up. No smoke. ...[/quote]
Did you measure all 4 supply voltages? The lighting LED will only tell you that you probably have more than ~8V on your +15V rail. If you flipped your +/- voltages for the metering board and your 10R resistors went south, the polarized caps on your metering board also have seen reversed voltages until these current limiting resistors burnt up and may be blown or short. Why don't you do it step by step. Disconnect the metering board, check your supply voltages, check if unit passes audio when bypassed, check if compression works, reconnect your metering board and adjust sensivity. If any step fails, fix this fault before continuing. Most of this is probably better described in the previous posts.
-Harpo

 

[Jonkan]

This has probably been asked before, but i cant find the info when searching.

Im curious about this: Why aren't the 22uf electrolytics in the signalpath just before the 27K resistors leading up to the VCA inputs bypassed with film caps?
The ones that are just after the unbalancing ne5534 stage.

The rest of the signalpath electros are bypassed, so thats why im wondering about this. Any idea of adding some here, or is there a special reason why there isnt any in the first place?

/J

 

[gyraf]

..at that point we have predictable, low-impedance signal, the others refer to unpredictable "external" impedances. That was the thought at the time of design, anyway. You could always bypass these as well, if you like - but not much comes from it imo..

Jakob E.