GSSL HELP THREAD!!!

[Gustav]

I only got the unit to work with everything else than ST Microelectronics regulators.....

How do you identify the brand on the part? (Would save some headaches if I could avoid them).

Gustav

 

[Majestic12]

I only got the unit to work with everything else than ST Microelectronics regulators.....

How do you identify the brand on the part? (Would save some headaches if I could avoid them).

Gustav

It has ST written on the front, but I can't remember exactly how it looked exactly. But I will instantly notice if I see one again . I'll have a look in my workshop if I can find some of those parts and take a picture, but most likely I have thrown them all away.

When ordering 78xx regulators from "Reichelt" I always got ST brand.

I bought a bunch of new regulators from RS Components, this time from Fairchild. Never had any problems with those

 

[tzman]

I only got the unit to work with everything else than ST Microelectronics regulators.....

How do you identify the brand on the part? (Would save some headaches if I could avoid them).

Gustav

It has ST written on the front, but I can't remember exactly how it looked exactly. But I will instantly notice if I see one again . I'll have a look in my workshop if I can find some of those parts and take a picture, but most likely I have thrown them all away.

When ordering 78xx regulators from "Reichelt" I always got ST brand.

I bought a bunch of new regulators from RS Components, this time from Fairchild. Never had any problems with those

Could it be the one on the left in the picture? The one on the right actually is a genuine ST, but does work as far as I know. The one on the left doesn't...

 

[Majestic12]

Yes exactly. The left one is the brand that doesn't work.
As I said I always got those regulators when I ordered 78xx from Reichelt. I don't know if other vendors have those in stock.

 

[Harpo]

Anyway you want to measure all your DC supply voltage rails (+15VDC, -15VDC, +12VDC, -12VDC, maybe Aux.+12VDC, each rail in respect to 0V reference voltage) in order to identify the buggy part(s).
When the 'Power On' LED doesn't lite up (this LED is powered by the +12VDC rail from 78L12 and only shows this +12VDC rail not operating correctly. There are at least 3 additional other DC rail voltages needed operating correctly in order to make the GSSL work), the 78L12 and/or 79L12, supplied from the +15VDC/-15VDC, could be the culprit as well.

 

[weiss]

Anyway you want to measure all your DC supply voltage rails (+15VDC, -15VDC, +12VDC, -12VDC, maybe Aux.+12VDC, each rail in respect to 0V reference voltage) in order to identify the buggy part(s).
When the 'Power On' LED doesn't lite up (this LED is powered by the +12VDC rail from 78L12 and only shows this +12VDC rail not operating correctly. There are at least 3 additional other DC rail voltages needed operating correctly in order to make the GSSL work), the 78L12 and/or 79L12, supplied from the +15VDC/-15VDC, could be the culprit as well.

is it weird that i have the same problem? i power on, the lights won't go on and the vu meter stops at the half of the scale. as soon as the vu meter goes to the left again after powering off, i turn the device on again and everything works fine.

btw i used the pcb grinder parts..

 

[Majestic12]

Anyway you want to measure all your DC supply voltage rails (+15VDC, -15VDC, +12VDC, -12VDC, maybe Aux.+12VDC, each rail in respect to 0V reference voltage) in order to identify the buggy part(s).
When the 'Power On' LED doesn't lite up (this LED is powered by the +12VDC rail from 78L12 and only shows this +12VDC rail not operating correctly. There are at least 3 additional other DC rail voltages needed operating correctly in order to make the GSSL work), the 78L12 and/or 79L12, supplied from the +15VDC/-15VDC, could be the culprit as well.

is it weird that i have the same problem? i power on, the lights won't go on and the vu meter stops at the half of the scale. as soon as the vu meter goes to the left again after powering off, i turn the device on again and everything works fine.

btw i used the pcb grinder parts..

No, thats not weird. Same problem here.... change the 78xx and 79xx regulators to a different brand than ST and everything will work just fine.

 

[Harpo]

i power on, the lights won't go on and the vu meter stops at the half of the scale. as soon as the vu meter goes to the left again after powering off, i turn the device on again and everything works fine.

VU meter and Power-On LED are supplied from the +/-12V rails. As both rails use the +/-15V vregs as preregulator in the latest pcb revision, this might only be a symptom from 7815 hanging on startup, or the 78L12 is hanging on startup because the 79L12 comes up faster. Either use different manufacturer for the 7815, 7915, 78L12 and 79L12 or try the anti-latching diodes.

 

[weiss]

No, thats not weird. Same problem here.... change the 78xx and 79xx regulators to a different brand than ST and everything will work just fine.

you mean ts? taiwan semiconductors? the st parts should actually work like tzman said.
do you know an online shop which has the working regulators in stock? on mouser i found houndreds of different regulators, don't know which one fits my board..

weiss

 

[Harpo]

Never had a problem with the TexasInstruments parts, IE uA7815, ua7915 for the TO220s and ua78L12, ua79L12 for the TO92s.
The 7812 for the single aux.rail will not hang on startup.
Mouser and Digikey (didn't look further) have stock.

 

[weiss]

Never had a problem with the TexasInstruments parts, IE uA7815, ua7915 for the TO220s and ua78L12, ua79L12 for the TO92s.
The 7812 for the single aux.rail will not hang on startup.
Mouser and Digikey (didn't look further) have stock.

that's what i searched for! thanks harpo

 

[Chehands]

Hi all,

Has anyone added extra meters to the gssl? I was thinking along the lines of using the ammeter for the gain reduction, and a pair of vu meters wired to the input and output.

 

[Harpo]

Has anyone added extra meters to the gssl?

I always thought 19" width and 1HE hight sufficient and kind of standard, but YMMV  ;D

I was thinking along the lines of using the ammeter for the gain reduction, and a pair of vu meters wired to the input and output.

With 4 additional VU meters or 4 LED bargraph meters, simultaneously showing the amplitude of left side input, right side input, left side output and right side output, your size of box will need to extend in order to make room for the electromechanical VU meters or the bargraph circuits with upsized PSU. Maybe have a look at the Expat Audio WM site for an additional VU driver circuit, showing all 5 selectable signals at a single *true VU meter.

*edit: not mA meter

 

[Jimmy1980]

Hi all,

I'm so glad to be joining the community!

I've had success building the hairball 1176 but I've hit a pretty big snag with my gssl, and I'm hoping someone here might be able to be of assistance.

When I run signal through my gssl, the Right channel sounds very distorted and choked. the Left channel is having the same issue but is much more quiet (almost inaudible) compared to the Right. The only thing I can tell is working properly is the power button and the meter, which seems to be responding to the threshold control but doesn't affect the sound. And the sound doesn't really change when I engage the compressor switch.

I've been trying to troubleshoot by checking for shorts, and there doesn't appear to be any from what I can tell. All of the board's components appear to be properly oriented. If I power the unit off while signal is running through it, the signal seems to sound good for a split second as the power fades out.

Could someone please explain in detail how to check the +- 12 and +- 15 rails? I not quite sure where to place my probes and don't want to ruin anything. I couldn't find any detailed information on this back through the thread.

Any help with this would be much appreciated.

Thanks so much!

Jim

 

[weiss]

When I run signal through my gssl, the Right channel sounds very distorted and choked. the Left channel is having the same issue but is much more quiet (almost inaudible) compared to the Right. The only thing I can tell is working properly is the power button and the meter, which seems to be responding to the threshold control but doesn't affect the sound. And the sound doesn't really change when I engage the compressor switch.

go and check your vca ic's. it is possible that they don't really stick in the sockets, try pushing them further in while sound goes through your device - you may hear a difference. i had the same problem and now everything is working fine.

 

[Jimmy1980]

When I run signal through my gssl, the Right channel sounds very distorted and choked. the Left channel is having the same issue but is much more quiet (almost inaudible) compared to the Right. The only thing I can tell is working properly is the power button and the meter, which seems to be responding to the threshold control but doesn't affect the sound. And the sound doesn't really change when I engage the compressor switch.

go and check your vca ic's. it is possible that they don't really stick in the sockets, try pushing them further in while sound goes through your device - you may hear a difference. i had the same problem and now everything is working fine.

Thanks weiss, I triple checked all of the ICs last night and they all seem to be locked in nicely.

I'd like to try checking the rails but I'm a little uncertain about how to go about it. Could someone please explain how to do this?

Thanks,

 

[weiss]

Thanks weiss, I triple checked all of the ICs last night and they all seem to be locked in nicely.
I'd like to try checking the rails but I'm a little uncertain about how to go about it. Could someone please explain how to do this?
Thanks,

then it has to be another problem.

 

[Jimmy1980]

Hey all,

So, I figured out how to read all of the voltages. Everything looks good throughout the board except for pin 4 on my input 5543's and left vca 5543, and both pin 4 on my output 5532's. I'm only measuring about 2v on each of these pins when I believe I should be measuring -15v.

It looks as though all of these pins should be fed -15 from the same source. Can anyone tell me where the problem may be? I can't seem to find it, but maybe I'm looking in the wrong places...

My right vca 5534 is measuring +/- 15 correctly.

Thanks,

 

[johnnyscotch]

I just started putting together the new GSSL SC from Gustav,

there are two 27k resistors with an * , one 47k* and a 120k*

Do these have something to do with the SC? Do you normally populate them if you are using the SC, or the reverse?

cheers

 

[Harpo]

So, I figured out how to read all of the voltages. Everything looks good throughout the board except for pin 4 on my input 5543's and left vca 5543, and both pin 4 on my output 5532's. I'm only measuring about 2v on each of these pins when I believe I should be measuring -15v.

Assuming typo 5543 for the NE5534 (single opamp chip, not a VCA), you either measured the wrong pin for V DC in respect to 0V reference voltage or the battery in your multimeter might be low, giving silly readouts. All NE5532 and NE5534 opamps use the same +/-15VDC supply rail voltages. Measuring the NE5534s between the chips pin 4 and 7 will give the same 30VDC readout as well as when measuring the dual opamp chips NE5532s between pin 4 and 8.