GSSL HELP THREAD!!!

[Harpo]

could it be something on the control pcb?

No.
Feed both channels of your GSSL with a constant signal (sine wave, keyboard, ..), so your unit is heavy compressing, at least in the working channel, and compare DC control voltages with a meter, starting at prementioned 1K resistors and follow the schematic. (NE5534 pin3, both L/R values equal? next NE5534 pin6, next VCA pin3,...). When left and right DC voltages don't match, the previous or following part could be faulty or has wrong value.

 

[mikerisha]

could it be something on the control pcb?

No.
Feed both channels of your GSSL with a constant signal (sine wave, keyboard, ..), so your unit is heavy compressing, at least in the working channel, and compare DC control voltages with a meter, starting at prementioned 1K resistors and follow the schematic. (NE5534 pin3, both L/R values equal? next NE5534 pin6, next VCA pin3,...). When left and right DC voltages don't match, the previous or following part could be faulty or has wrong value.

ok.. some of my values arent matching on the ne5534s. but all my components are correct in the VCA section. DC matched up all the way to the NE5534, and begins to vary at pin 3. and the 100p on either dont match voltage wise as well.

i have another board populated that i am gonna compare against. this is awfully frustrating.

 

[radiance]

.. this is awfully frustrating.

Some would call this a "learning experience" 


Seriously, if all my builds would have worked first time I would have learned nothing...

 

[mikerisha]

I just replaced 2 .1 caps on the right channel.

Here are my readings on my NE5534s

Right Channel:
Pin 1 11.34
Pin 2 0
pin 3 0
pin 4 -14.92
pin 5 -1.27
pin 6 0
pin 7 14.62
pin 8 12.06

Left Channel:
pin 1 12.20
pin 2 0
pin 3 0
pin 4 -14.92
pin 5 -.64
pin 6 0
pin 7 14.62
pin 8 12.16

100p readings (next to 5-8 side of 5534):

Right channel, left leg (closest to PSU side) -1.26
Right channel, right leg:  12.03

Left Channel, left leg: -.64
Left channel, right leg: 12.10

??? ???

 

[audiophreak]

Hi,
    Happy New Year to All,
                                    Mine has started with the completion of a Dual GSSL with Turbo, got the inspiration from some awesome looking Dual LA2As in the DIY Gallery. I'm very happy with it, works like a charm, and sounds great.

  Here is a link to some pix,  http://picasaweb.google.com/audiophreeek/DualGSSL?feat=directlink

  mikerisha ,  I'm sorry that I have not a clue to help you, I have built one single GSSL and this one, its so hard to diagnose these kind of things over the internet, But the people of this forum do just that. I can tell you I had to just trudge through with the schematic, and with the help of a few members here, got me pointed in the right area,  I had a couple of solder bridges ( shorts ) , and two wrong value resistors ( order of magnitude ) .  I believe it says on Gyraf page to  , Check, check and re-check.

  Thanks to Jacob and Gyraf, and everyone in this community.

 

[radiance]

Here are my readings on my NE5534s

Are those the input 5534's?

 

[mikerisha]

Here are my readings on my NE5534s

Are those the input 5534's?

no those are from the left and right VCA sections.

 

[radiance]

Ok, was just confused by the statement below....

Right channel, left leg (closest to PSU side) -1.26
Right channel, right leg:  12.03

Left Channel, left leg: -.64
Left channel, right leg: 12.10

 

[Harpo]

Here are my readings on my NE5534s

Right Channel:
pin 3 0
pin 6 0

Left Channel:
pin 3 0
pin 6 0

There is no compression. 0V control voltage is the VCAs bypass condition (current in=current out), probably caused by missing or too weak audio signal.
The THAT218x VCAs in this circuit operate by a control voltage of -6.1 mV/dB applied to pin3.
For a heavy compression, maybe 20dB, this would be 20 * -6.1mV = -0.122V or -0.061V for 10dB compression. Numbers are easier to compare when the VCA is set for max.compression.
In this DBX202 substitution circuit this control voltage (not 0) could then be measured at the non inverting impedance buffers NE5534 pin 6 and pin 3.
In front of both op-amps non inverting input (pin 3) is a 1K/120R voltage divider to scale down the control voltage law (search for THAT design note DN127) of the THAT218x (-6.1mV/dB) to the DBX202C,X,XL,2001 (-50mV/dB), so before this voltage divider (junction of both 1K resistors where the control voltage is split to the left and right VCA) I'd expect something like -1,139V for 20dB compression or -0,569V for 10dB compression for previous example settings.
Again, start at these 1K resistors as already mentioned in previous post.

 

[redmojosteve]

This is just a bit of general advice. I have recently completed a second GSSL and it didn't work correctly. Basically compressed and uncompressed signals were the same. I checked for dry joints, solder bridges and corrected any as required. I replaced a damaged resistor in the sidechain which looked like it had been given a knock from a tool! Voltages generally seemed OK. I finally removed the ICs and checked all of the components again and I found that the 14pin DIL socket was faulty. It wasn't a rolled pin type and some of the the small "clamps" for the pins were damaged and must have been from day 1. When you are checking you have to assume that anything could be faulty. Fortunately I didn't have too much else to do between Christmas and New Year's day...
It's now working well and is installed in my home studio.

 

[pietro_moog]

hi guys.
i didn't repair my gssl yet, i'm about to make an order with some components.

i have a problem, i need to power 2 5532 and a led for a balancing amp to place before the gssl.
do you think it's a problem if i connect them to the +/- 15 rail of the gssl?
i mean making an hole in the back panel, place a connector and make a small cable.
do you think i should connect even the ground of the 2 circuits?
do you think a metal 2,1 dc connector would be good for this operation?


my gssl has a turbo board and SSC board, but i'm not using the relay.
my trafo 2x15 secondaries, 1A.
i don't think is gonna be a problem at all, but i'm just looking for a confirmation.

 

[radiance]

hi guys.
i didn't repair my gssl yet, i'm about to make an order with some components.

i have a problem, i need to power 2 5532 and a led for a balancing amp to place before the gssl.
do you think it's a problem if i connect them to the +/- 15 rail of the gssl?
i mean making an hole in the back panel, place a connector and make a small cable.
do you think i should connect even the ground of the 2 circuits?
do you think a metal 2,1 dc connector would be good for this operation?


my gssl has a turbo board and SSC board, but i'm not using the relay.
my trafo 2x15 secondaries, 1A.
i don't think is gonna be a problem at all, but i'm just looking for a confirmation.

Why do you need a balancing amp before your gssl? Gssl IS balanced...or do you need it for something else? Either way, if you're going to use the gssl's power you also need to connect the ground.
You're saying "two circuits" but you should see it as one circuit.

Even better, to understand grounding you should see your whole studio as 1 circuit 

 

[pietro_moog]

thanks.
i need a balancing amp because the source is -10dbV, and if the gssl is designed for +4dbu i'll miss about 12db of gain.
more noise and sweet spot missed..

yeah.. i never really understood the concept of ground, i didn't find a good and simple lecture on ground yet..

well, so you're saying there's no problems with 2 5532 more,right?

thanks

 

[peteys]

Hi,

I can't seem to get my 2180's into the cut half of the 16 pin sockets.  It seems as if the pins on the 2180's which are flat and wider that the other chips on the board which fit perfectly into their sockets.  Am I doing something wrong?  Appreciate any help.  thank you.

 

[Autophase]

my SSL is coming along nicely, got all the comonents on there, just waiting for the headers and meter to arrive.
I havent soldered and jumpers on yet, this might sound like a silly question but can i just use the excess wire from some spare resistors as jumper wire?

 

[Biasrocks]

can i just use the excess wire from some spare resistors as jumper wire?

Yes, I prefer something a bit heavier gauge like rectifier diode clippings, but resistor legs will certainly do the trick.

Mark

 

[Autophase]

cheers for the reply.
Another question.
On the board where do the 4 wires from the transforer go? The + & - for each of the 2 15 secondarys.

Also coult I use THIS http://www.rapidonline.com/Electrical-Power/PA-Audio-Video/PA-Audio-Kits/Mono-VU-meter-10-LEDs/74663/kw/vu meter?
What mods would i need to make?

 

[Biasrocks]

cheers for the reply.
Another question.
On the board where do the 4 wires from the transforer go? The + & - for each of the 2 15 secondarys.

Also coult I use THIS http://www.rapidonline.com/Electrical-Power/PA-Audio-Video/PA-Audio-Kits/Mono-VU-meter-10-LEDs/74663/kw/vu meter?
What mods would i need to make?

Have you read this thread or searched for this information here, because I suspect that answers to your questions lay there.

A quick search for "GSSL transformer connection" turned this up.

Topic: Main transformer 2x115 wiring

http://www.groupdiy.com/index.php?topic=19533.msg228144#msg228144

Mark

PS: that first one was a freebie.  8)

 

[peteys]

Does anybody have any advice on how to get the 2180's in the cut half of a 16 pin socket?  Do they fit?  Am I not pushing them hard enough.  I bought the ones from Greg's BOM.  Digikey ED60002-ND

I'd really appreciate it.  I've read all of the posts but can't seem to find an answer.

 

[radiance]

  Do they fit? 

They should...

Am I not pushing them hard enough. 

 

Probably..

I've read all of the posts but can't seem to find an answer.

Post a picture from your attempt...