kante1603
Well-known member
You're welcomeguze said:
Udo.
GSSL HELP THREAD!!!
- Thread starter hairyandy
- Start date
Help Support GroupDIY Audio Forum:
Udo.
My meter now shows GR ~1db with no input signal on one of three ratio settings with no turbo board attached and turning the threshold pot will cause the meter to show quick intense GR. The phantom GR goes away when the sidechain is bypassed and when I turn the unit on or off, the needle slams to the right.
I posted about this a bit ago, but I have now tried a few things and gathered some more info. My unit functioned properly before I attempted the turbo addition and this same problem developed after I added the turbo. I thought it had to be due to the turbo, so I tried taking it off. I found that the problem was still present. I am kicking my self for somehow messing up my properly functioning gssl.
I am thinking that maybe I fried a capacitor in my turbo installation attempt and current is leaking through to the meter somewhere. No idea if this is correct, but at one point with the turbo attached, the needle was slamming all the way to the right at a constant rate of 1click/second. Seeing as I am in the US and my home uses 60Hz power...I stretched to reach my conclusion about a capacitor.
What do you all think? Definitely upset with my self for messing up my working unit....Live and learn I guess.
Cheers,
Jeff
I posted about this a bit ago, but I have now tried a few things and gathered some more info. My unit functioned properly before I attempted the turbo addition and this same problem developed after I added the turbo. I thought it had to be due to the turbo, so I tried taking it off. I found that the problem was still present. I am kicking my self for somehow messing up my properly functioning gssl.
I am thinking that maybe I fried a capacitor in my turbo installation attempt and current is leaking through to the meter somewhere. No idea if this is correct, but at one point with the turbo attached, the needle was slamming all the way to the right at a constant rate of 1click/second. Seeing as I am in the US and my home uses 60Hz power...I stretched to reach my conclusion about a capacitor.
What do you all think? Definitely upset with my self for messing up my working unit....Live and learn I guess.
Cheers,
Jeff
wthrelfall
Well-known member
Another plea for help.. my gssl is still an expensive ugly ashtray :-(
Harpo
Well-known member
Posting some close up pics from traceside and component side around the sidechain section as well as the control board might give us a hint.wthrelfall said:
Reason for misbehaviour seems to be too much control voltage reaching the Ec- ports of your audio-VCAs. (what polarity and voltage is this at VCAs-pin3 with and without signal present ?) This could be caused by multiple reasons, such as shorts, wrong value or wrong orientation components, such as the tantalum caps at the release switch, or FI an opamp stage running open loop because of poor soldering or a broken pcb trace.
wthrelfall
Well-known member
Harpo said:
OK, so I generated a 1V ac signal and measured pin 3 on the vca's, they are measuring 0.77vac and 0.75vac. I then cut the signal and measure again, but this time they both measure 1.6vac. So I disconnect the input and output connectors from the pcb and re-test pin 3's on the vca's, this time they measure 3.3vac.
I think I've decided to strip it down and start again, for all our sakes!
Harpo
Well-known member
You measured AC voltage, giving an RMS readout without polarity (and the result seems bad enough to expect both VCAs blown from exceeding the abs.max. +/-1V between pins2/3). My question was for polarity and voltage.
Alright guys, I have been doing some testing with my multimeter to try and discover why I am getting a phantom meter reading on certain ratio settings. My meter problems go away when I take out the TL074, but come back with multiple different TL074 chips. Darn. I oddly find continuity between the positive pole of my meter and my chassis ground. I am thinking this should not be and may indicate a ground short somewhere as the cause of the problem. Could someone please check and see if they have continuity between their meter's positive pole and their ground.
Thanks,
Jeff
Thanks,
Jeff
jjaskuna said:
Ill be back and able to test in about 5days but what do you mean? Ground being *star ground on gssl chasis connected to common terminal on dmm. Possitive pole being poss dmm connected to? Not sure what u say here
Maybe its me tho hehehe
wthrelfall
Well-known member
Harpo said:
Harpo, I've got a new pcb and have decided to start over.. thanks so much for trying to help - I think I just need to start again and be very careful how I build it. I'd like it if somebody could confirm that these capacitors I have are suitable before continuing? Please see photos..
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wthrelfall
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Harpo
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Caps from pic 1 and 5 look fine. Pics 2,3,4 probably fine as well, but these only show 100V rated CzeroGs at whatever capacitance and some paper claming 10pF, 22pF and 100pF. Just have a look at the caps other side. Might show 10J, 22J and 101J for your chosen 'J' parts tolerance.
Identifying parts values is part of your DIY homework. If in doubt, get the parts datasheet, read it and learn something on the way that might make more and more sense to you, the more you read.
Identifying parts values is part of your DIY homework. If in doubt, get the parts datasheet, read it and learn something on the way that might make more and more sense to you, the more you read.
wthrelfall
Well-known member
Oh joy! the re-built compressor is working! thanks to everyone who contributed to my cause, I will not forget you!
wthrelfall
Well-known member
wthrelfall said:
but my right signal is down 12db
wthrelfall
Well-known member
wthrelfall said:wthrelfall said:
but my right signal is down 12db
OK, sorted.. don't know how but who cares, sounds GREAT!
wthrelfall said:wthrelfall said:wthrelfall said:
but my right signal is down 12db
OK, sorted.. don't know how but who cares, sounds GREAT!
Im glad its sorted! What do you mean rebuilt? Same pcb and whole new batch of components or same pcb?
just curious!Thumbs up
wthrelfall
Well-known member
ptron said:wthrelfall said:wthrelfall said:wthrelfall said:
but my right signal is down 12db
OK, sorted.. don't know how but who cares, sounds GREAT!
Im glad its sorted! What do you mean rebuilt? Same pcb and whole new batch of components or same pcb?
Thumbs up
new pcb with old components, new resistors...
"Ill be back and able to test in about 5days but what do you mean? Ground being *star ground on gssl chasis connected to common terminal on dmm. Possitive pole being poss dmm connected to? Not sure what u say here
Maybe its me tho hehehe"
My grounding scheme is: Ground from audio input of pcb connected to right XLR input ground, Jumpered to Left XLR input ground, jumpered to a screw that is drilled into the chassis. Also connected to this screw is a wire that attaches to the ground of my ICE power connector. Not sure what a star ground is thought....
By "positive pole of my meter", I mean: the connector on my meter that the red wire attaches to. The red wire then attaches to Meter+ or M+ (can remember which it is on my PCB) on the control PCB.
Jeff
Maybe its me tho hehehe"
My grounding scheme is: Ground from audio input of pcb connected to right XLR input ground, Jumpered to Left XLR input ground, jumpered to a screw that is drilled into the chassis. Also connected to this screw is a wire that attaches to the ground of my ICE power connector. Not sure what a star ground is thought....
By "positive pole of my meter", I mean: the connector on my meter that the red wire attaches to. The red wire then attaches to Meter+ or M+ (can remember which it is on my PCB) on the control PCB.
Jeff
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