GSSL HELP THREAD!!!

[drj88]

Does the mounting bolt touch the top of your case?

Nope. I haven't put the top on yet. I think I may have the blue and brown wires the wrong way round, but am I right in thinking that this shouldn't actually prevent it from working? If I understand correctly, it is less safe though, so I shall switch them round at some point anyway.

I have linked to some pictures I took, so maybe you can spot a problem. (Note: images are nearly 4mb each)

PCB: http://imageshack.us/a/img24/449/s7o5.jpg
full view: http://imageshack.us/a/img189/1838/3a90.jpg

 

[Engels]

Solved the prevoius problem with my own will 

So far so good, turned on for the first time my ssl;
I can say that 3/4 of this circuit is fine!
Rails shows;

+12VDC
-12VDC

+15VDC
-16,4VDC !!! (****)

I initially though that the main problem concerned the 7915;
Then I measured secondaries and the results are 19VAC (Transformer is a Myrra 45034 / 10VA / 2x15V)
I'm kinda confused on how to wire secondaries since the datasheet say the opposite of what's written here...
Have I to use a configuration which doubles the secondary voltage?

P.S: I haven't managed to put a meter on my unit; I need to concerning about or doesn't make any difference?

 

[Harpo]

Just wondering if in the UK this toroid would be fine:
http://uk.farnell.com/multicomp/vtx-146-030-115/transformer-30va-2x-15v/dp/1675052

Yes, as long as you don't intend to operate it in a 115VAC mains land.

The reason I'm confused is it says it's 1A but I'm sure the recommended amps was 10A, or am I mis-understanding.

1A is the transformers secondary AC current load rating from your link. It is a 30VA transformer. 30VA / (15V+15V) = 1A. The recommended rating is 10VA (not 10A) for the GSSL circuit. If your build has addons, such as Turbo, sidechain filter(s), relais, illumination, ..., the transformers VA rating most likely needs an increase to deliver the DC current demand of these addons, but 30VA seems ample for the usual suspects.

 

[Harpo]

I think I may have the blue and brown wires the wrong way round, but am I right in thinking that this shouldn't actually prevent it from working? If I understand correctly, it is less safe though, so I shall switch them round at some point anyway.

Doesn't matter inside your box.

I have linked to some pictures I took, so maybe you can spot a problem.

Main problem seems your secondaries transformerwires pcb connection. Using a magnifying glas might help to spot and remove the short between the center pin and an outer pin of your AC connection on pcb. Soldering these wires from traceside seems adventurous and already might have broken/lifted a pcb trace from soldering heat and mechanical force/weight of wire. Fit wires from component side (and use a Y wiering for the center tap connection) or use a 3-pin terminal (screw)connector with 0.1" or 0.2" pin spacing (that's why there are 5 holes on pcb).
Maybe optical artifact, but pics seem to show some XLR-pins1 shorting to other XLR-pins2/3.
Get the center red wire from the pcb output connector away from below your pcb and insulate its open wire end so it doesn't short things out, if you wouldn't cut it off. Twist each pair of at least input hot/cold wires between XLR/pcb, so the balanced line receiver has a better chance to cancel out induced garbage.
Missing jumper at sidechain insert.
...just some of the most obvious from component side.

 

[Harpo]

Rails shows;
-16,4VDC !!! (****)

Without load connected (no opamps fitted), the 7915 will give a higher readout. A temporary 1K ... 1K5 between 0V and the -15VDC rail most likely will prove propper regulation of -15VDC.

Then I measured secondaries and the results are 19VAC (Transformer is a Myrra 45034 / 10VA / 2x15V)

Secondary voltages will read 15VAC at rated load. Voltage will read higher with transformer less-/unloaded.

Have I to use a configuration which doubles the secondary voltage?

No. You connect both 15VAC secondary windings in series (giving a 30VAC center tapped transformer), this series junction being the center tap connection that goes to the center hole of the AC connector on pcb.

P.S: I haven't managed to put a meter on my unit; I need to concerning about or doesn't make any difference?

No difference (assuming 'a meter' is the 1mA FSD meter to show the amount of gain reduction)

 

[hchahi]

So just to recall, are you guys using THAT2180LA without a problem on the SSL compressors??
I'm about to buy some and would like to know, since we don't have that good old data...

cheers!

Hey bud my name is hardy and can anyone tell me if I can put the that corp vca 2002t in the gssl buss compressor kit from pcb grinder? That corp vca is telling me I can only use the 2181vca. I'm very confused can someone please let me know. Also what is the difference between 2181 and that corp 2002t?

 

[Engels]

Rails shows;
-16,4VDC !!! (****)

Without load connected (no opamps fitted), the 7915 will give a higher readout. A temporary 1K ... 1K5 between 0V and the -15VDC rail most likely will prove propper regulation of -15VDC.

Then I measured secondaries and the results are 19VAC (Transformer is a Myrra 45034 / 10VA / 2x15V)

Secondary voltages will read 15VAC at rated load. Voltage will read higher with transformer less-/unloaded.

Have I to use a configuration which doubles the secondary voltage?

No. You connect both 15VAC secondary windings in series (giving a 30VAC center tapped transformer), this series junction being the center tap connection that goes to the center hole of the AC connector on pcb.

P.S: I haven't managed to put a meter on my unit; I need to concerning about or doesn't make any difference?

No difference (assuming 'a meter' is the 1mA FSD meter to show the amount of gain reduction)

that's a nice synthesis indeed 
Thank you a lot;

I'm assuming I've to put opamps in their sockets and try to read traces voltage a second time, or as you suggest, I'll first try with a resistor;
great! I'm trying right now...

 

[Harpo]

Hey bud my name is hardy and can anyone tell me if I can put the that corp vca 2002t in the gssl buss compressor kit from pcb grinder? That corp vca is telling me I can only use the 2181vca. I'm very confused can someone please let me know. Also what is the difference between 2181 and that corp 2002t?

A THAT2181 is a single VCA, a THAT2002T is a VCA-module, consisting of 4 paralleled VCAs and some surrounding circuit. Just google That DN127.pdf to get the idea/differences.
You could make the two audio-VCAs THAT2002Ts in this kit work IF you understand the complete circuit of the GSSL (and have the measuring equipment to make use of differing parameters). Some parts on the GSSL pcb will need different values for correct operation.

 

[drj88]

Missing jumper at sidechain insert.

Ah, thanks for spotting that. I completely overlooked it. I just put it in now.

Main problem seems your secondaries transformerwires pcb connection. Using a magnifying glas might help to spot and remove the short between the center pin and an outer pin of your AC connection on pcb. Soldering these wires from traceside seems adventurous and already might have broken/lifted a pcb trace from soldering heat and mechanical force/weight of wire. Fit wires from component side (and use a Y wiering for the center tap connection) or use a 3-pin terminal (screw)connector with 0.1" or 0.2" pin spacing (that's why there are 5 holes on pcb).

I re-soldered those wires before adding in the sidechain jumper. Made no difference. I resoldered them again after adding the jumper and now the toroid seems to be working fine. Had it powered up for a few minutes so far and no excessive heat, no burning smell, seems good. 7915 voltage has changed to -22v though. What is the voltage supposed to be? I had it at -15v before.

Anyway, the +15v and -15v rails are working perfectly, so that's good. I passed some audio through it and the meter seems to work fine, threshold works, I think all the controls are working in fact. The led dims when I turn the make up gain to full. Not sure why. Not a big deal though.

7815 and 7812 still read 0v. Is the 7812 only used for the +12v relay? If so, then I guess I don't really need that anyway. As for the 7815, isn't that for the +15v rail? My +15v is working fine, so maybe my 7815 is too, I dunno. Is there a diagram or something that shows the correct voltages?

Twist each pair of at least input hot/cold wires between XLR/pcb, so the balanced line receiver has a better chance to cancel out induced garbage.

Ok, I'll do that.

Maybe optical artifact, but pics seem to show some XLR-pins1 shorting to other XLR-pins2/3.

Those aren't actually shorted. Picture just makes it look that way.

Get the center red wire from the pcb output connector away from below your pcb and insulate its open wire end so it doesn't short things out, if you wouldn't cut it off.

It is already insulated. Just not visible on the picture. Anyway, thanks for all the suggestions. Seems to be pretty much working now. And thanks to everyone else who took the time to respond.

 

[Everland]

Hi all,

I've been off here for a month or so whilst other work called.

I have managed to fix my previous voltage problem on the 12V rail, which turned out to be a faulty 79L12.

I have now run into the next problem: the unit passes audio but compression is not working at all on either channel. The make-up gain control works but none of the other controls have any effect on the audio whatsoever. Could someone please let me know how to go about tracking down the problem. Thanks in advance.

Ben

 

[frazzman]

Hi all,

I've been off here for a month or so whilst other work called.

I have managed to fix my previous voltage problem on the 12V rail, which turned out to be a faulty 79L12.

I have now run into the next problem: the unit passes audio but compression is not working at all on either channel. The make-up gain control works but none of the other controls have any effect on the audio whatsoever. Could someone please let me know how to go about tracking down the problem. Thanks in advance.

Ben

Hi Ben - have you checked to make sure all your connections from the 10 pole header of the control PCB to the mainboard are good? From memory is the 'c' connection is dodgy you won't get compression. Also is the bypass switch wired properly? Again, if thats not you won't get any compression either.

 

[Everland]

Hi Frazzman!

I checked all the connections from control PCB to mainboard and they are all good.

I checked the wiring of the bypass switch and stupid me, I had wired it incorrectly. However, I corrected this wiring and I'm still not getting any compression.

Thanks for your suggestions so far, do you have any other ideas?

 

[Harpo]

I checked the wiring of the bypass switch and stupid me, I had wired it incorrectly.

Depends on the switch connections at gain makeup between pot wiper and 620K resistor. If you have connected 0V reference voltage at bypass position for improved bahaviour, this part of switch has to be turned around, so contrary to schematic "E" has to connect to the switches pole and the throw positions either switch to the makeup pot wiper or 0V reference voltage. If you get this wrong, you short out the +12V rail when turning the pot full CW.

However, I corrected this wiring and I'm still not getting any compression.

If you have the latest pcb revision (you never told us), might be missing jumper at sidechain insert ?

 

[drj88]

Hi, things seem to be mostly working for me, except one channel is much louder than the other. I checked my cables and they seem to be fine. I had a quick look at the pcb to see if I could spot any resistors of incorrect value, but couldn't. I measured the 5532s on the output and noted the results below. Not sure how useful that is for diagnosing the problem, but I though it might help a bit.

RIGHT 5532

these readings are with audio being sent through

pin 8 0
pin 7 0
pin 6 0
pin 5 15v
pin 4 -15.06v
pin 3 0
pin 2 0
pin 1 0

these are with no audio going through (but xlr cables still connected)

pin 8 0
pin 7 0
pin 6 -0.11v
pin 5 15.00v
pin 4 -15.06
pin 3 0
pin 2 0
pin 1 0.12

LEFT 5532

these readings are with audio being sent through

pin 8 0
pin 7 0
pin 6 0
pin 5 15.00v
pin 4 -15.06
pin 3 0
pin 2 -0.01
pin 1 (varies with audio, between 0.0 and 0.2)

these are with no audio going through (but xlr cables still connected)

pin 8 0
pin 7 0
pin 6 0
pin 5 15.00v
pin 4 15.06v
pin 3 0
pin 2 0
pin 1 0

 

[Harpo]

Hi, things seem to be mostly working for me, except one channel is much louder than the other. I checked my cables and they seem to be fine. I had a quick look at the pcb to see if I could spot any resistors of incorrect value, but couldn't. I measured the 5532s on the output and noted the results below. Not sure how useful that is for diagnosing the problem, but I though it might help a bit.

RIGHT 5532

these readings are with audio being sent through (but I won't tell you at what level in AC voltage I send audio in)
pin 8 0 +15V
pin 7 0
pin 6 0 this is a current- not a voltage node
pin 5 15v 0V
pin 4 -15.06v
pin 3 0
pin 2 0
pin 1 0

these are with no audio going through (but xlr cables still connected)

pin 8 0 +15V
pin 7 0 -0.11V would be V DC offset. Audio is V AC without sign
pin 6 -0.11v current in
pin 5 15v 0V
pin 4 -15.06
pin 3 0
pin 2 0
pin 1 0.12 maybe +0.11VDC, followup from pin7
...snipoff

edited some of your mixed up pin numbers for the 1st section... (looking up the parts datasheet or checking how pcb traces connect would have given you this idea as well.)
Voltage at pin 1 is a followup from output voltage at Pin7 (NE5532-Pins 5,6,7 are Pins 3,2,1 from schematic and vice versa, opamp stages are swapped), so at least the last inverting right side stage (pins1,2,3) seems to work correctly. (the left side NE5532 will be measuring error at pin7 when pin1 is varying audio between 0.0 and 0.2 at whatever AC or DC voltage it might be)
Pull the audio-VCAs out of their (hopefully fitted) socket and fit a wire jumper (or biro or whatever else handy) between VCA sockets pins1/8 to bypass the VCAs and measure again.

[rant]This has been answered numerous times. Why can't builders be bothered to read at least some of the last pages of this thread.[/rant]

 

[Everland]

If you have the latest pcb revision (you never told us), might be missing jumper at sidechain insert ?

Aha! Is that where the PCB is marked *HPF? I need to wire a jumper across there?

Edit: Yes it is!! Done and comp is working!! Sounds good!

Thank you to all that helped on here.

 

[Dissler89]

Started building this unit about a month ago.
Kudos to pcbgrinder for the parts and Tat for the casing.

I'm boiling down to ordering the last few parts and I have a nooby question referring to the Powerswitch.
I realise the Switch needs to be SPDT with a Max 250VAC. But I'm somewhat confused about the amperage.
Is a max 3A Switch ok to use? Or is 5A preferred?
After searching the forum 5A is what people mostly seem to use.

If someone could share some light on me it would be appreciated.

Thanks

 

[Fuccimain]

Hi.

Would anyone mind pointing me in the direction for some info on how to get a 3rd power supply tap to feed relays and illuminated switches? 12v should do. I did a search for regulator latching but I couldn't make heads or tails of what I got from that.

Thanks or any info or direction to info

 

[MeToo2]

Started building this unit about a month ago.
Kudos to pcbgrinder for the parts and Tat for the casing.

I'm boiling down to ordering the last few parts and I have a nooby question referring to the Powerswitch.
I realise the Switch needs to be SPDT with a Max 250VAC. But I'm somewhat confused about the amperage.
Is a max 3A Switch ok to use? Or is 5A preferred?
After searching the forum 5A is what people mostly seem to use.

If someone could share some light on me it would be appreciated.

Thanks

The actual power draw is way way less than 1A at ±15V. Mains current will be a few milliamps steady state after the initial switch on surge. If you're using a toroidal transformer that surge can be significant. It's then a question of electrical safety for your country of what is appropriate. Higher ampere rating on a switch is generally fine. [hint: you haven't filled in your country of origin in your profile]

 

[MeToo2]

Hi.

Would anyone mind pointing me in the direction for some info on how to get a 3rd power supply tap to feed relays and illuminated switches? 12v should do. I did a search for regulator latching but I couldn't make heads or tails of what I got from that.

Thanks or any info or direction to info

For relays and other non-critical applications, a 7812 is perfectly acceptable. e.g. this one

How you connect it up depends on what you have already. There are no relays on the standard GSSL board.

If you have a spare tap available on your existing transformer, you could use that complete circuit including the "rectification" section, or if not, you could connect the "smoothing" part to your existing bridge rectifier that feeds the +15V regulator (possibly via a 10R resistor or a diode for some more filtering).

Make sure you fit "flyback" diodes on your relays.

I had to cut some traces on my SSC filter board to get it working the way I wanted (cut ground connections and default whether relay powered up or not)