GSSL HELP THREAD!!!

[MeToo2]

I have a number of these EAO switches, does anyone know if they are suitable for use on the GSSL?
http://products.eao.com/index.php?IdTreeGroup=124&IdProduct=48307
thanks.

It depends entirely on what you want to do with them. The standard (Aarhus) GSSL only needs a power switch and a bypass switch. There appears to be one normally open and one normally closed contact and a lamp (which is not switched) on these switches http://products.eao.com/media/zoom/piz12849_zoom.jpg The bypass switch needs DPDT, so that's no good, and the mains switch needs 250VAC switching and the max rating on these is 42V so that's no good either. But of course they could be used to switch a 24V relay.....

 

[wthrelfall]

Ah, ok.  So basically no.  Which EAO switches could be used for bypass?

thanks.

 

[greyskull]

Hey guys, finlly finished all the soldering and 99% of the metal work.

Powered up the unit without VCA's just to make sure it was all good.
+15 and -15 measure up right.
+12 and -12 Mesure up fine too.

There was a great guide of voltages to test on the main PCB that I now can't seem to find. (searched and searched!) Any clues?

Secondly,  with makeup gain turned all the way up, the bypass switch turns the Power LED on and off. When any where else it functions normally..

I should also say that I've wired this unit With a CRC AND turbo board as well. the turbo board seems to be getting 12v fine as well, and power of CRC seems good.

Last but not least! How would one wire up the LED backlight on the hairball sifam style meter?

Cheers!


EDIT!

Plugged the unit In and audio is Being passed, but compression seems way outta wack., meter is also not responding, and the output cranked is making the power led cut out....

All the voltages on the main board measure up okay.... must be the bypass Right?

Guy

 

[Nanitlig]

Hello, I'm new to the forum and building my first GSSL.  I have a few questions regarding relays.  I'm wanting to use two 12V Omron DPDT relays that I had around from another project.  One half of the first one to switch the "Turbo" S/C board and the second for engaging HP filters at both S/C inputs. 

1. Should I install an additional 78L12 regulator to power these instead of tapping into the +12V link at the 10-pin header?

2. I have IN4004 diodes paralleled across the DC terminals of the relays, as suggested in the datasheet.  Should I be using .1uF decoupling also?

3. Is it OK to link the +12V to both relays, parallel?  The first relay ("turbo") is switched at the 0V side using the 4P3T, which also switches bypass, the make-up link and 3 LED's, one for each mode (Byp., Normal, Turbo).  The second (HP relay) is switched on the 0V side as well, with a DPDT mini-toggle, which also turns on a LED.  The 0V points of both switches return to the "OFF" point of the control board.  Should I have resistors at the (+) terminal of each relay, like 10R?

Much thanks!
Nanitlig

 

[synnys]

I've built a gssl with superside chain, everything seems fine, except for compression

Bypass works, make up gain works. compression does not work, not any of the controls.

I must say, i have not connected a panel meter yet as i didn't arrive yet. Is this the reason why?

can i connect the +/- for the meter with a little jumper? does is work then? or will i destroy something?

It's actually my third build, i double checked all solder connections and the thing is built very neat..

 

[synnys]

I've built a gssl with superside chain, everything seems fine, except for compression
Bypass works, make up gain works. compression does not work, not any of the controls.
I must say, i have not connected a panel meter yet as i didn't arrive yet. Is this the reason why?
can i connect the +/- for the meter with a little jumper? does is work then? or will i destroy something?
It's actually my third build, i double checked all solder connections and the thing is built very neat..

Nevermind! Got it working, forgot to connect the SW pole on the sidechain board.  8)

 

[greyskull]

okay. After some intense searching this forum I Have Compression!! Switched A and c on the bypass switch!

Still have no meter at the moment though.... any ideas anyone?

 

[Nanitlig]

Ok, thought I had it figured out, but I'm still having issues... I would like to set up my GSSL for unbalanced operation only.  Everything I've tried I end up with the right side being down about 6dB from the left.  Also, when grounding out the hot of either side, I still hear bleed of the right in to left/left in to right.  Everything seems in order.  I can get both sides to be at the same level on their own, so I'm pretty sure all components are soldered well and amps are working as they should.  I've been able to get both sides at the same level, however it involved lifting grounds causing buzz.  Is there anyone who has set theirs up for unbalanced operation who could help me out?  I've seen a few posts about changing some resistor values at the VCA.  Could I just change the R1 27k in to the right VCA to compensate for the tilt?  Placing a 20k parallel across the 27k sounds pretty close.  18.5k? 

 

[greyskull]

Would this ALSO be related to the Bypass switch? DPDT toggle style? CHEERS!
Guy

 

[jjaskuna]

Hey Guys,

I was really hoping to figure this out through reading this meta thread without having to ask for help, but I have been unsuccessful in solving my problems so I come to you all hoping you can save me before I throw in the towel. 

My Gyraf GSSL passes audio fine but does not compress and none of the controls have an audible effect. I unfortunately do not have a scope to accurately trace signals through the board. So, I tried measuring to see where AC current went when a signal was applied. I did this be placing one meter probe at my right positive XLR input and the other meter probe at various places on the board. (I have no clue if this is even a viable technique, but I tried it anyway)  I found that only when an audio signal is present I find AC current at pin 1 of my TL074. The signal value at pin 1 changes depending upon position of bypass switch (i.e. left or right) between ~10mA and 6mA, respectively. Additionally, the signal at pin 1 is affected by the threshold pot.  I do not, however, measure any AC current at TL074 pin 7, which sends signal to the sidechain as I understand it. I have tried two TL074CNs and I TL074CNE. The CNE gives lower current readings at pin 1--~1.5mA AC.

From what I gathered and measured, I think that I am not getting any compression because there is no signal going to my sidechain. I think that my controls/switches (well at least the bypass and threshold) are working due to the changes in AC current.  Does anyone have an idea as to what is going on and what I should do?

A few other potentially useful observations:  My power on LED does work, I have the correct 15V/+15V and 12V/+12V rails (I did have to replace a 7195 initially to get the 15V rail working correctly), I show correct power voltages at the TL072 and TL074, I have tried different TL072, TL074 and THAT2180A( 2180c's as well).

Any thoughts or help anyone has is greatly appreciated. I am feeling quite defeated

Jeff

 

[Nanitlig]

Despite the right channel being 6dB down, I was still able to use my GSSL this weekend mixing live with it across the drum buss.  Sounded pretty awesome!  ;D I just had to run my group 2 fader at +6dB.  I did stumble upon some cool sounds accidentally when I set the ratio control halfway between 4:1 and 10:1, so the ratio contact was open.  I was able to completely smash the drums this way, like 12-14dB and they still sounded huge.  So, I'm wondering if I adjust the switch to make it 3P4T, and have the 4th position be a latched setting with the ratio contacts left open.  Is there potential to blow anything up doing this?  Is it at all like what's going on with the Smart C2 Crush feature?  Not something I'd use all the time, but it was PERFECT for having to mix metal bands tonight!  <-- My metal face...

 

[wthrelfall]

Please excuse my ignorance, but can anyone explain how I wire this transformer to the GSSL board and IEC socket?
cheers..

 

[Harpo]

Please excuse my ignorance, but can anyone explain how I wire this transformer to the GSSL board and IEC socket?
cheers..

Transformers secondary connection: tie red to orange and take this center tap connection to the center hole of your AC connection on GSSL pcb. Yellow and black to the adjacent holes, order doesn't matter for AC.
Transformers primary connection: Blue to IEC neutral. Brown to mains switch throw position. Mains switch pole position to fuse holder. Other lug of fuse holder to IEC hot. IEC safety ground to case. Connecting your transformers inner connection wires gray and violet depends on your local AC mains voltages 115/230/...
This is a intercontinental forum and not only mains voltages differ, so updating your profile with your location data doesn't seem such a bad idea...

 

[wthrelfall]

Please excuse my ignorance, but can anyone explain how I wire this transformer to the GSSL board and IEC socket?
cheers..

Transformers secondary connection: tie red to orange and take this center tap connection to the center hole of your AC connection on GSSL pcb. Yellow and black to the adjacent holes, order doesn't matter for AC.
Transformers primary connection: Blue to IEC neutral. Brown to mains switch throw position. Mains switch pole position to fuse holder. Other lug of fuse holder to IEC hot. IEC safety ground to case. Connecting your transformers inner connection wires gray and violet depends on your local AC mains voltages 115/230/...
This is a intercontinental forum and not only mains voltages differ, so updating your profile with your location data doesn't seem such a bad idea...

Thanks, it's UK, 230v. 

 

[Harpo]

Thanks, it's UK, 230v.

Transformers primary connection for 230VAC mains in series: Tie violet to gray and isolate this further not needed connection, so this doesn't any harm when getting in touch to you or to the case.

 

[Nanitlig]

I finally got both sides at the same level using unbalanced cables.  I lifted the cold pin on just the left input at the pcb.  For some reason grounding the cold pin at the left input is making the input NE5534 jump about 6dB.  I thought doing so was supposed to make the amp drop 6dB?  At any rate, it's working great now and both channels are at the same level and the A/C mV readings at all in/out amps and sidechain are the same.  I suppose if I wanted to put in a switch for going between balanced or unbalanced I could use a SPST for that pin3/ring connection. 

I'm still curious about a fourth ratio setting which leaves the ratio circuit open and if doing so could possibly cause any serious damage.  I made it through mixing an hour long set pushing it in this fashion and it survived.  Any thoughts?

Thanks!
Nanitlig

 

[wthrelfall]

Thanks, it's UK, 230v.

Transformers primary connection for 230VAC mains in series: Tie violet to gray and isolate this further not needed connection, so this doesn't any harm when getting in touch to you or to the case.

Thanks Harpo, that's cleared it up. 
Another question which I can't find the answer to:  I am using a plastic case for the GSSL, how do I attach the ground or do I need to?

 

[Harpo]

I finally got both sides at the same level using unbalanced cables.  I lifted the cold pin on just the left input at the pcb. For some reason grounding the cold pin at the left input is making the input NE5534 jump about 6dB. 

??? .. to normal level. The debalancing line receiver NE5534 is operating the potential difference between inverting and non-inverting input. Leaving one input pin floating/disconnected might give a maybe funny, hardly repeatable, but not a reliable result.

I thought doing so was supposed to make the amp drop 6dB?

The output stage. Leaving the last inverting stage disconnected (never shorted to gnd) will give you this 6dB drop.

I suppose if I wanted to put in a switch for going between balanced or unbalanced I could use a SPST for that pin3/ring connection.

Whatever your pin3 might stand for, using a TRS (Tip/Ring/Sleve) connector, you tie ring to sleve or using XLR connectors tie XLR-pin1 to XLR-pin3. If you want to keep your signal in stereo in balanced mode, this switch better will be a DPDT.

I'm still curious about a fourth ratio setting which leaves the ratio circuit open and if doing so could possibly cause any serious damage.

Just move the lockwasher from pos.3 to pos.4 at your ratio rotary switch. A TL074 isn't that picky.

 

[Harpo]

Another question which I can't find the answer to:  I am using a plastic case for the GSSL, how do I attach the ground or do I need to?

You can't, but to make your box safe in case a mains wire inside comes loose, you'd have to connect this safety ground from your IEC to any conductive spot to the outside world (pot housing when metal knobs attached to metal/conducting spindle, sleve of unisolated TRS sockets, ..). This will not protect your circuit inside your plastic case from induced garbage (radiating transformer from a unit below/above, RF, neons, ...)

 

[Harpo]

So, I tried measuring to see where AC current went when a signal was applied. I did this be placing one meter probe at my right positive XLR input and the other meter probe at various places on the board. (I have no clue...

! 
Welcome Jeff,
take the (usually black wire) meter probe and connect the plug side of this wire to your 'COM' socket at your multimeter. Other side of this wire (probe tip, croko-clip, ..) connects to your circuits reference voltage (0V). For the GSSL, one of the most easy to attach spots for this 0V might be the wire link between 1000uF cap and 7915 voltage regulator.
The other (usually red) probe wire connects with one end to the 'V' socket at your multimeter.
With multimeter turned on and dialed in for measuring -in this case- AC Voltages (not current, probe would need a connection to a different socket) you get your voltage reading when probing around to trace a (maybe 1V sine at 500Hz) signal applied to your input thru your powered circuit.
Good luck