GSSL HELP THREAD!!!

[Mattnezz]

All this started with the GSSL, so here's my almost ultimate! Had a wonderful month of work on this one...

 

[Chrome Heart]

verry nice job.

 

[dirtyhanfri]

Hi, after some weeks, i could spend some time on it yesterday...


The 3rd release position issue was solved by cheking the 560k resistor, it was actually 100r, so I swapped it and it's fine now

I replaced the 7815 because my +15v rail was not too stable, I thought it could be the cause of the hum, now, my +15v is ok, but the noise is still there.

Also, the issue when powering on the unit stays, but only with IC's plugged, with no IC's on the sockets, the unit turns on perfectly...

Measuring voltages I noticed the V on pin 4 of the right channel 2181 gave me something like +10v, and nothing in the other channel, and I've got more noise on right channel than left.... but the IC doesn't get hot, and the comp actually works...

The hum stays at -58 dbfs and goes up to -40 with make up gain turned fully clockwise, maybe it is related to the tl072? I remember I got some sparks when measured the 12v on the regs for first time but the voltages were ok...

some tips about this? I'm thinking in doing a star ground and see if that helps with the hum...

 

[RATMNL]

Hey All,

I am about to wire the toroid tarnsformer, including switch, using Harpo's pictures on p. 251.
http://www.hausverwaltung-heger.de/al_leck_trick/GSSL_psu_hookup.gif

thats pretty much the exact situation, with a DPDT switch. Now, the label on my Transformer is confusing me...
I'm using this transformer: http://nl.rs-online.com/web/p/toroid-transformers/6718924/

Now the label says: PRI: 230V BLU-BRN.. that I get..
now onto the SEC: 15V/7.5VA, BLK-RED & SEC: 15V/7.5A ORN-YEL

The picture says i should wire the Black & Yellow together to form ground, and use ORN & RED to link to + & - repsectively.
but that means taking wire No. 1 from the first secondary and wire No. 2 (as noted on the label) from the second pair... while in the picture it comes across that the RED would be wire NO. 1 from the first secundaries and YELLOW No.1 from the secundaries, reading top down... so that the pairing would actually be RED-BLK & YEL-ORN instead of the other way around.

Can someone shed some light on this, if it even matters if you switch the RED one for the black one and ORN-YEL, or am I making too big a deal out of this and should just wire it according to the picture...

Regards,

Mark

 

[Harpo]

I am about to wire the toroid tarnsformer, including switch, using Harpo's pictures on p. 251.
http://www.hausverwaltung-heger.de/al_leck_trick/GSSL_psu_hookup.gif

answer to #4472 obviously related to a different transformer. Colour coding of transformers is not standarized.

thats pretty much the exact situation, with a DPDT switch.

maybe similar situation. got fused IEC-inlet or separate fuseholder ?

Now, the label on my Transformer is confusing me...
I'm using this transformer: http://nl.rs-online.com/web/p/toroid-transformers/6718924/

Now the label says: PRI: 230V BLU-BRN.. that I get..
now onto the SEC: 15V/7.5VA, BLK-RED & SEC: 15V/7.5A ORN-YEL

The picture says i should wire the Black & Yellow together to form ground, and use ORN & RED to link to + & - repsectively.

The picture says, you should join the in-phase winding end (indicated by a dot) of the 1st secondary winding with the out-of-phase winding end of the 2nd secondary winding for a transformers secondary center tap connection that further goes to the center hole of the external transformer connection on GSSL-pcb. One of the remaining two secondary wires goes to the AC connection hole to the left, the other goes to the AC connection hole right to the center tap connection hole.

 

[RATMNL]

Thanks for the Reply,

I was afraid about non-standardizing in the transformer, but I couldn't find any dots on the wires, So I looked at the datasheet of teh Trans. and it shows about the same:

15V BRN 0V BLU
Red SeV - Blck oV,
Yellow Vsec - Red 0v

So It would be the same as the wiring in the picture? black & yellow tied down togther down the middle and either (??) of the other wires to left and right...

I use a Fused-IEC-inlet...

 

[jjaskuna]

I am starting my second GSSL and am going to add a turbo board to this one. I am having some problems getting my 2x15V 30VA toroidal transformer (back ordered....for a while) and am looking at other options. I am looking at a 2x18V 160VA toroidal transformer, but am concerned with the high 160VA rating. From looking at the schematic and a search of this tread, it seems that the 2x18V will work, but will the 160VA be too much for this project. I hope it will work as I cannot find anything else in the US at a reasonable price.  Here is the link to the transformer:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=122-610

Thanks for any help!

Cheers,

Jeff

 

[Harpo]

...but am concerned with the high 160VA rating...

and maybe concerned with the hight of this 160VA rated toroid that won't fit inside a 1HE boxes inner dimensions.
Transformers power rating should be enough to run >10 GSSLs simultaniously.
In a 10% high mains scenario the abs.max. input voltage of the 78L12/79L12 will be exceeded with this 36V (more likely the 39V nc ideling value) center tapped transformer, so maybe increase the voltage dropping 10R resistors in front of the 78L12/79L12 to maybe 150R/1W for assumed ~30mA current draw per 12V rail. YMMV.

 

[RATMNL]

Ok, I'm measuring up my GSSL, with just the TL074 mounted (because I read that somewhere)

+15/GRND@OUT: +14.98 = Yay!
-15/GRND@OUT: -14.98 = Yay!
+12/GRND@OUT: 11.98 = Yay!
-12/GRND@OUT: -12.16 = Yay!

(the pcb is a little confusing in thsi, for it looks like you have to measur up the 22u cap over there, which results in weird meter behavior, the trace next to it reads the correct voltages. note that i have little electronics knowledge except for what I learned building the GSSL)

Anyway, continue:
Fitted NE5534 (x4) one by one: voltages check out. Sort of.. the -15v/grnd drops a little with each component placed... we're talking 0.01V - 0.1V per component, so I continued.
Fitted TL072 (x1): no mayor fluctuations
Fitted Main VCA (x2) one by one : By now voltage read:

+15: 14.97
-15: -14.70 <- THE ONLY ONE CHANGING, though given closed circuit this could actually be what's supposed to happen. I really don't know, If I remember physics class from LOOOONG ago, a circuit needs to be closed between + and 1 and with all the components in the way it might just be normal (I feel really bloody stupid right now)

+12: 11.97
-12: -12.06

Fitted SC VCA: -15V = 14.60
Fitted NE5532 (x2) and final voltages read the same, just -15V ends on 14.40V...
Should be allright? Anyway: POWER ON!

it passes audio! and there is compression! threshold, ratio, attack and release seem to work, there's just a problem with the makeup-gain pot. In bypass mode, when all the way down, it turns  off the LED next to it.. when not bypassed, it doesn't seem to give any gain, except for when it's turned all the way Down (??) it makes an audible noise (volume-change or the like) returns to what seems to be the input level (compared to the bypass), and turns of the LED again...

I am about to change the bridge connection between the two boards, for that's a bit of the worst soldering known to man (molex connctors don't quite place themselves on the PCB as I hoped they would) so maybe that'll fix things (wish the UPS came with my desoldering-gun) but if not... any ideas? I looked for solderbridges and the like but couldn't find anything. Is there anything I can measure to small down the options to look for?

Regards, and apologies if I ask/am doing stupid things,
It's my first build

Mark

 

[gyraf]

there's just a problem with the makeup-gain pot. In bypass mode, when all the way down, it turns  off the LED next to it.. w

Look for shorts at the control pcb - specially around the wiring to mainboard..

 

[dirtyhanfri]

Also, the issue when powering on the unit stays, but only with IC's plugged, with no IC's on the sockets, the unit turns on perfectly...

Measuring voltages I noticed the V on pin 4 of the right channel 2181 gave me something like +10v, and nothing in the other channel, and I've got more noise on right channel than left.... but the IC doesn't get hot, and the comp actually works...

The hum stays at -58 dbfs and goes up to -40 with make up gain turned fully clockwise, maybe it is related to the tl072?

some tips about this? I'm thinking in doing a star ground and see if that helps with the hum...

Well, I tried a ground star, isolating pcb from chassis, triying to get 0V to the board in just one point and nothing of this works, my hum stays there, actually I'm thinking in get a new board and new comps and start again.... :-\moving the wires doesn't make any effect, I have recheked for shorts or something weird with no luck...

Any help or things to look about? Right now is in my bench, just with the output connected to a behringer cheap mixer and that to a fostex monitor

Thanks

 

[RATMNL]

Ok, Everything Works!! Except the Meter...
I am using this Hairball one:
http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=61
so the 330R resistor bridging it is not necesary.

I measured the voltages at the meter and at M+/M- to see if it passes current, and voltages check out 14.98 etc. so it shouldn't be a wiring issue? but somehow the meter refuses to move even a bit.

kinda at a loss here, so close to the finish

 

[RATMNL]

Ok nevermind the above. I bought a different 1mA meter from the local shop and that one doesn't move a muscle either... checking connections again is the way to go, but after that I have no idea what to do... Any possibilities that spring to mind?

EDIT: totally disgregard, one resistor directly after the G return on the mainboard, a resistor didn't make proper contact... I have MY FIRST WORKING GSSL with the Hairball mter!!! Now wait for the bodywork to arrive on mondays and I'll post some pictures...

http://hairballaudio.com/shop/product_info.php?cPath=25&products_id=61

Does anyone know how to Wire the two LEDS in the meter? You'll blow them when attached to the secondaries like you would a "lamp" right?

and would I have to modify anything if I wanted to replace those with either one of these:

http://nl.farnell.com/kingbright/l-144hdt/led-rect-red/dp/1142606?Ntt=1142606

http://nl.farnell.com/kingbright/l-144idt/led-rect-he-red/dp/1142602?Ntt=1142602

I got some lying around and since my entire machine will be black, red and white, I thought it might be cool to have the meter illuminated red...

 

[RATMNL]

Man, I feel like SPamming this thread....

anyway, a little weird thing... The ratios seem to be backwardly assigned to the lorlin switch, ie. pos1 compresses the most while pos 3 does the least.... I think I read somewhere that switches are supposed to be symmetrical, so turning it wouldn't do anything to solve this right? I don't want to desolder the entire switch before I know if it would actually fix something. Logic would state that pos 1 compresses 1:2, 2 1:4 3 1:10...

Any ideas? Not quite sure what would have caused such a thing...

Thanks... Again..

Mark

 

[gyraf]

Hi Mark,

We've been there before several times. Make sure to read this thread (or at least significant parts of it). 

Hint: threshold changes with ratio

Jakob E.

 

[RATMNL]

Hey Jacob,

I did Search this thread a LOT (!!), (though admittedly, now that my GSSL is getting close to completion, and my school project deadline is getting quite close (how awesome is my school ) , i find myself getting a little impatient), but with the wrong idea what to search for, you get no/wrong results..

Anyway, with that cleared out of my mind, (still don't know the how and why, but I'm gonna push through this here 266 pages to figure out why...) and my GSSL "apparently" working, only thing left to do is to completely check it up voltage/pinwise/calibration...

Don't know how yet, but I;m sure I'll find it in here somewhere

Sorry for the Impatience, I'll be good now

 

[jjaskuna]

Hey All,

I am planning on using 1/4" TRS female jack instead of XLR for both input and output on my GSSL. Just wanted to check my wiring plan before I proceed. I am planning on using basic TRS wiring,  Tip (+), Ring (-), Sleeve (Chassis) for both input and output female jacks. I found a wiring scheme somewhat applicable to my plan else where in this thread, which I based my plan on as well. It is quoted below.

I will be feeding my GSSL from send/return inserts (Tip=send and Ring=Return) on my console with balanced cables.  My concern is that when I measured continuity with my 1/4" cable plugged into my insert splitter I found that (for the tip send) the tip of the splitter is connected to the tip of my inserting balanced cable, the chassis of the insert-splitter is connected to both the chassis and the ring of my inserting balanced cable. Will this be an issue with my planned wiring scheme?


Thanks for your thoughts.

Cheers,

Jeff

Input is on 5 pins:

O + Left.  Pin 2 on left XLR. Goes to left TRS jack tip.
O - Left.  Pin 3 on left XLR. Goes to left TRS jack ring.
O Ground.  Pin 1 on both XLRs. Goes to both TRS jack sleeves.
O - Right.  Pin 3 on right XLR. Goes to right TRS jack ring.
O + Right.  Pin 2 on right XLR. Goes to right TRS jack tip.

Output is also on 5 pins but + and - swapped, and also right and left swapped:

O - Right.  Pin 3 on right XLR. Goes to right TRS jack ring.
O + Right.  Pin 2 on right XLR. Goes to right TRS jack tip.
O Ground.  Pin 1 on both XLRs (should go from XLR to star ground, not to here)
O + Left.  Pin 2 on left XLR. Goes to left TRS jack tip.
O - Left.  Pin 3 on left XLR. Goes to left TRS jack ring.

 

[id3alism]

hey guys,
I recently finished my gssl and it worked nearly perfect. The only problem was, that I did get distortion after about 10 minutes of use. I noticed that the voltage regulators 7815 and 7915 get very hot. The voltages on the board seemed to be okay at that time. So I decided to equip the regulators with cooling fins and mount them on the chassis. After that I connected them with wires to the original positions.
But now as soon as I switch my comp on, the bridge rectifier (500V, 2A) starts smoking and dies.

What could be the problem?

 

[Harpo]

So I decided to equip the regulators with cooling fins and mount them on the chassis.

Missing isolation kits ? (the regulators metal fins are internally connected to different potentials)

 

[id3alism]

So I decided to equip the regulators with cooling fins and mount them on the chassis.

Missing isolation kits ? (the regulators metal fins are internally connected to different potentials)

So the fins of the regulators have to be completely isolated from everything? Didn't know that...
Need to check that out.
Thanks!