GSSL HELP THREAD!!!

[Greg]

Run a wire from the EARTH (GND), not Neutral, from the IEC to the chassis. Then connect that with pin 1 of the input (and output if you like) XLRs.

 

[Greg]

Look Here:

GSSL Wiring Pic

 

[rstreber]

Thanks for your response, Gyraf. I tried swapping out 2180s, and that doesn't make a difference. So far, all my resistor values are correct and I can't find any bad solder joints, but I'll triple check. I'm using one of Chef's PCBs, so it's very clean.

What's happening specifically is that it seems like the R channel is fine until the the audio goes above a certain level, and then it spikes and clips very hard. For example, I was running stereo overheads through it and I can set it to a lower level where both channels sound fine until the the snare goes just beyond a certain point, and then the R channel output pops and is totally clipped. The left channel is always fine. Compression is happening on both channels, and when I set the level below this "threshold" where R channel clips, the two seem sides seem almost equivalent - R channel is just a little hotter. When I put it in bypass or turn up the makeup gain to match the bypass level, R channel is totally clipped. Again, all controls seem normal and the meter works fine. Could it be a bad cap or something?
Any thoughts? Thanks!

 

[zboy2854]

Great, thanks Greg! :thumb:

 

[Hulk]

I just got my toroid (Talema TRT30215, 230V-2x15V) transformer today but I'm having a hard time figuring out how to connect the wires because I don't have any information about the color of the wires - There's two yellow wires with extra insulation, one blue, one red, one green and one brown - I have found the specs for the Talema (pdf) here but the color codes for the wires in the specs does not match the colors of the wires on my toroid :?

Does anyone know this model and help me identify the wires??

 

[rstreber]

I'm still trying to figure out my R channel distortion problem; I'm tracing signal around, but, being a very new newbie, I'm not confident that I know what's abnormal or what to look for.
I'm getting very distorted signal at pin 1 and 8 of the R ch. 2180, and no signal at the L channel 2180 - should there be audio here? I'm also getting distorted audio just after the R unity gain 27k resistor and no audio here on the L ch. And I'm getting clean signal at pin 8 of the SC 2180 but distortion at pin 7. If anyone can give me some pointers as to what I should idealy be finding / hearing, I'd greatly appreciate it!! I'm learning a lot as I go through this ciruit, but I still know woefully little about what's actually going on in this thing!!
Thanks

 

[Zee1usa]

Hello,

I finished my GSSL and it is compressing on both channels, but one is
louder than the other.

I injected a 1kz sinewave into XLR's and here is what i noticed.

Left Input: NE5534 pins 2(IN-),3(IN+),5(comp),6(OUT) are the SAME size waveform. No change at all?!?#$?

Right Input: NE5534 pins 2(IN-),3(IN+) waveform are same but 5(comp),6(OUT) are DOUBLE in size waveform compared to pins 2,3.

I believe the "Right Input" is correct it is the "Left Input" pins 5(comp),6(OUT) which have not DOUBLED in size as I am thinking they should be.

I checked all my voltages they all look good. I have checked resistors, checked for solderbridges etc. I swapped NE5534's without change. I swapped the VCA's without any change.

All components stuffed are correct around the NE5534 circuits.
I checked all these.


Any insight would be appreciated!

Thanks,

Z

:wink: :guinness:

 

[t-wurst]

Need some help please guiding me in the right direction.

Problem:
I wired and fired up 2 of those nice SSL.
One board came out a bit dirty due to a crappy solder tip and i forgot to wipe off the photostuff with aceton.
The other board looks pretty good. Everything is shiny, got a brandnew tip, measured every resistor before it´s soldered (except of the MegaOhms cause my DMM is too small (!) - uh, maybe there´s the fault?! )
I have all the right voltages +/- 15 +/- 12, the XLR´s are grounded, the unit passes audio. dbx in right direction (used verbos´). I have bridged the Makeup/Bypass conn. on the control board with a jumper because i still miss the switches. (both bypass points and the com/on points) Meter works like it should, threshold drives the meter different, meter follows signal.
BUT
Makeup doesn´t work, there is no audible compression and in my opinion, the voltage regulators getting too hot. It takes maybe one or two minutes, then u can´t touch them much longer than a few seconds. Maybe this is normal, i used 2x18V torroid? So i switch it off and don´t have much time for measurements.. :?
Voltages vary on 074 pin 7, somewhere between +0,15 and -1,9 Volts, i measured 072 pin 8 i think, but there are not the voltages inverted like Jakob suggested.

The same behavior with the other control board.
I don´t had much time last week, maybe today i can spend a few hours...

Any hints? Thanks in advance :wink:

toby

 

[Zee1usa]

Bump...


I am having OP AMP issues with my XLR in NE5534 output pin 6.

I really just need to know what the output signal pin6 should look like
compared to the input signals pin 2/3?

Is it amplified or is it soposed to be at unity?

I am getting 2 different results on output and I just wondered which is correct? Please see my post above.

Thank you for any insight you may offer,

Z :?

 

[Greg]

Gyraf:

I've come across a slight problem with my latest GSSL that I'm building for a mastering engineer here in New Orleans. The GSSL itself works great... my question is regarding a metering issue. I decided to go with the Modutec meter from Mouser. I'm trying to scale it so 6dB gain reduction is fully deflected. In fact, I was actually going to wire in a switch for 2 scales... one from 0-3dB and one from 0-6dB. But for some reason (even with the 2K resistor replaced by a short) I'm only getting 40% deflection. I'm assuming it's a meter issue since I had a spare Weston that I could fully deflect with no problem at 6dB GR. I was just wondering if you had any ideas to get more current to the meter. Maybe a current amplifier I guess, but that'd be a pain in the !@#?

I know I can use a different meter, it's just that I already have the front panel all drilled out for this meter.

Thanks.

 

[Mundox]

Hey Greg, I am using the same meter, and I get 30db reduction full scale with a 1k resistor! I think it's the meter. So when the meter barely moves you get 2-3db reduction. Those meters are a bit slow .

 

[gyraf]

Greg,

Put in a trimmer for the 2K resistor, and adjust untill you think your meter makes sense.

Z,

There's either a wrongly-wired XLR, some short, or a wrong resistor somewhere around the input opamps. Check and recheck.

Jakob E.

 

[Greg]

Gyraf: That's what I did... but even with that 2K replaced with a dead short, it still only deflected 40% (at 6dB GR). My goal was to make 6dB 100% deflected. So I think, as Mundox suggested, this is not a very good meter.

 

[gyraf]

Nope, you'd need a different meter to do this then. Or possibly a second meter buffer, that will output enough current for your meter. Maybe two paralleled halves of a 5532?

What is it? 10mA full-scale? Isn't there an internal shunt resistor you can remove?

Jakob E.

 

[Greg]

[quote author="gyraf"]Nope, you'd need a different meter to do this then. Or possibly a second meter buffer, that will output enough current for your meter. Maybe two paralleled halves of a 5532?[/quote]
I'll talk to the guy I'm building it for and see what he wants me to do.

[quote author="gyraf"]What is it? 10mA full-scale? Isn't there an internal shunt resistor you can remove?[/quote]
The specs said it was 1mA full-scale, but it's obviously not. I'll check for an internal shunt resistor.

 

[Zee1usa]

[quote author="gyraf"]
Z,

There's either a wrongly-wired XLR, some short, or a wrong resistor somewhere around the input opamps. Check and recheck.

Jakob E.[/quote]


It appears that the Gustav board layout for input XLR'S is:

- + 0 + -

The gyraf board layout indicates:

+ - 0 - +


Am I the only one that has run into this issue or if I am wrong please correct me.

Thank you,

Z

 

[gyraf]

Gustav's boards are the latest revision. Known good.

Jakob E.

 

[Zee1usa]

Thank you for the response.

I reversed the XLR's opposite of the Gyraf diagram and now

my signals on pin 6 of both NE5534 look exactly the same.


I traced the wiring on Gustav's pcb and it appears to be opposite of the gyraf
diagram as mentioned above.

I want to believe Gustav's pcb is the same as the gyraf diagram, but it appears not. Do I have an older revesion of his pcb that may have been reversed? or...do i need to take two asprin and go to bed?

:?

 

[dukasound]

Hi
I found this small dual VU. Does anybody know some details and specification and can I use this in SSL. This is DC VU. I measured 603ohm across + and -. There is nothing inside meter (no resistor, diodes)

 

[cwatkins]

Problem:

I had the SSL working, (it ran for hours, I love it!, classic buss compresser) it had this problem at first, so I'm assuming
there is a short, but I'll be darned if I can find it.

Details:

If the control board is disconnected, everything seems to work great,
+6 db great quiet auido passes flawnessly, nothing how runs great.

Plug in control board and not the makeup gain pot, but the threshold pot,
if turned to right, makes the led go dim, now I saw gyraf make a reference to the makup gain pot causing the led to go off, but I can't find
that thread or a similar one that specs the threshold pot doing that. I've done some voltage traces back and foreth between the tl074 and the control board pins, check continuity on the cable and looked for the short, if the threshold pot is turned all the way down, in bypass mode, it almost works and passes audio, but anything to the right almost immediately causes the a large hum and no audio. and the voltage to drop to about 4v where it was 6.5.

anything sound familar?

on most of the pins and -10 where it was -12 before on the pot.