GSSL HELP THREAD!!!

[spudstyle]

I checked all my voltages and it's ok for all. TL74, NE5534, NE5532, TL72, THAT2180B are powered. Any idea ?

 

[Walcar]

Hello,

I'm new here (from Paris, France) and have just finished building a SSL clone using PCB Grinder's PCB and a toroidal transformer (2X15V/1A)

When i measure voltage on + & - 15v points on the Pcb, my voltmeter show: 6,XX volts; i've checked the resistors value in the PSU section: they are all ok

Does somebody have an idea for something going wrong?

 

[spudstyle]

Hello,

I'm new here (from Paris, France) and have just finished building a SSL clone using PCB Grinder's PCB and a toroidal transformer (2X15V/1A)

When i measure voltage on + & - 15v points on the Pcb, my voltmeter show: 6,XX volts; i've checked the resistors value in the PSU section: they are all ok

Does somebody have an idea for something going wrong?

Tu testes bien en continu ? As tu checké tous les voltages 1 par 1 en commençant par le début ? J'ai un problème similaire sauf que ça semble venir du transfo. Une fois sur deux je n'ai que 14v au lieu de 30v entre le +15 et le -15. Quand il me fait le coup, j'ai un des deux secondaires du transfo qui est à 0v... Va savoir pourquoi ! Je vais regarder ça plus en détail dans l'après midi et te tiendrai au jus si je trouve quelque chose d'intéressant. Là je fais une pause, j'ai galéré à faire compresser mon compresseur, 3 jours pour trouver qu'une soudure bavait sur une autre !

 

[Harpo]

When i measure voltage on + & - 15v points on the Pcb, my voltmeter show: 6,XX volts; i've checked the resistors value in the PSU section: they are all ok

Probing with the meters red wire, meters black/common wire connected to 0V, meter set to read DC voltage, your meter will not show 6.xx VDC or your meters battery might be low/empty.
There is no resistor in the +/-15VDC PSU section, so there is no value to check.

 

[spudstyle]

Ok, I got compression now (but with big ground noise), that was a soldering problem that put the sidechain to the ground.

But I still have a problem with my power stage, sometimes, when I start the compressor, I don't have the +12 & +15 but have the -15 & -12. I need to power off and on again to have it. Capacitor problem ? Or diode bridge ?

 

[Biasrocks]

But I still have a problem with my power stage, sometimes, when I start the compressor, I don't have the +12 & +15 but have the -15 & -12. I need to power off and on again to have it. Capacitor problem ? Or diode bridge ?

Answered earlier in this thread.

Search is your friend

http://www.groupdiy.com/index.php?topic=47.msg639266#msg639266

Regards
Mark

 

[phancak]

I have new problem with TRESHOLD sensitivity.
( without 47k resistor )

Treshold sensitivity is dependent to input signal - is OK?
Input signal 0 dB - treshold is active.
                  -20dB - treshold is half active

Voltage ( ratio 2, Attack 0.1, release 0.1, makeup min )
TL 072/ pin 1
Treshold min.  -0.14V
Treshold max.  2.97V


TL 074/ pin7
Treshold min.  2,2mv
Treshold max. -0.2mv

It's ok?

Thanks.

 

[Arnoid]

I builded my gssl a while ago and it worked from the first power up...

Last week I tryed to calibrate the ratio's, I use THAT2180BL for the VCA's and a 127K sidechain resistor.
I used a -15 db sine 1000 HZ testtone at the inputs and a 10db raise of the input signal this are the results:
2:1      4.70db  (Has to be 5db)
4:1      3.03db  (Has to be 2,5db)
10:1    1.59db  (Has to be 1db)
These results are a little weird I think ?  :


I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

 

[kosty]

Hi guys !

Last year I built the GSSL including Turbo and SSC successfully and now I was thinking about adding a Crush'n'Blend function.
The CnB seems to be good for parallel compression but I am not happy about how it influences the function of the make-up gain.

As far as I understand the circuit the Make-up gain adds an DC Offset to the CV of the main VCA (and the SC VCA too) and raises the overall level at the VCA output. Now that the Dry signal is mixed after this step in the output circuit the ratio between the Wet and the Dry signal changes if you raise or lower the level of the compressed signal with the Make-up Gain knob.

This means, that it's not possible to adjust the output gain (Wet + Dry signals) to match the bypassed signal and to compare the compressed signal with the original signal at the same level (it's possible if you adjust the make up and the wet / dry knob little to little until you reach unity gain, but it's not an ideal solution).

What I am looking for is to bypass the makeup gain (or replace the pot with a fixed resistor) and to add a gain control somewhere in the output circuit after the dry signal has been added to the wet signal.

Can someone help me realize that ?

I think the gain circuit has to be placed before the 100R of the + output and before the 10K of the negative input of the 2nd half of the NE5532.

I have very little idea about these things, so I hope someone skilled can push me in the right direction.
Many thanks !

 

[phancak]

I builded my gssl a while ago and it worked from the first power up...

Last week I tryed to calibrate the ratio's, I use THAT2180BL for the VCA's and a 127K sidechain resistor.
I used a -15 db sine 1000 HZ testtone at the inputs and a 10db raise of the input signal this are the results:
2:1      4.70db  (Has to be 5db)
4:1      3.03db  (Has to be 2,5db)
10:1    1.59db  (Has to be 1db)
These results are a little weird I think ?  :


I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

I recommend to replace the 127k resistor 91k and 50k trimer in series and  calibrated ratio.

 

[Arnoid]

I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

I recommend to replace the 127k resistor 91k and 50k trimer in series and  calibrated ratio.

Thx any idea's for the output signal ?

 

[spudstyle]

Ok, now my compressor is working but on my left channel, I got a ground noise. The right channel is ok, very low noise. My kit is from PCBGrinder and a capacitor was missing in the package (cause the BOM say 9x100pf and really need 10). I find another capacitor at home that is 100pf but not the same size cause it's a 500v (see attached picture). So this capacitor can be the problem ? In this case, what type of capacitor I need ? 50v, 100v ? I don't have the reference of PCBgrinder kit capacitor.
Thanks for your help.

 

[phancak]

I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

I recommend to replace the 127k resistor 91k and 50k trimer in series and  calibrated ratio.

Thx any idea's for the output signal ?

The idea is for setting ratio sensitivity - 91K rezistor + 50K trimer

For setting output signal replace 27K resistor (input THAT 218x - pin 1) to 50k trimer to fine setting.

 

[thepraqtice]

Have a couple of newbie power related questions... just starting to wire everything up.

This my power transformer:

https://dl.dropbox.com/u/4364451/gssl%20transformer.JPG

http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9530266

Is it ok for use in the UK (230V)? On the primary it has 2x 115V but on Farnell it says it can handle 230V. This has confused me a wee bit... How would I wire primary's up to my power switch Earth, Live, Neutral connections and what rating fuse should I use with it? If I can use it... My power switch is an integrated IEC inlet/Fuse holder/Switch
http://gb.mouser.com/Search/ProductDetail.aspx?R=KM00.1205.11virtualkey69300000virtualkey693-KM00.1205.11

I am also using an Expat CRC board inline. How would I connect the secondary's to the CRC and where is the best place to connect CRC board to GSSL and mount the voltage regulator?

Sorry for newb questions, this part I really want to make sure I don't mess up...

Many thanks

 

[MeToo2]

Have a couple of newbie power related questions... just starting to wire everything up.

This my power transformer:

https://dl.dropbox.com/u/4364451/gssl%20transformer.JPG

http://uk.farnell.com/jsp/search/productdetail.jsp?sku=9530266

Is it ok for use in the UK (230V)? On the primary it has 2x 115V but on Farnell it says it can handle 230V. This has confused me a wee bit... How would I wire primary's up to my power switch Earth, Live, Neutral connections and what rating fuse should I use with it? If I can use it... My power switch is an integrated IEC inlet/Fuse holder/Switch
http://gb.mouser.com/Search/ProductDetail.aspx?R=KM00.1205.11virtualkey69300000virtualkey693-KM00.1205.11

I am also using an Expat CRC board inline. How would I connect the secondary's to the CRC and where is the best place to connect CRC board to GSSL and mount the voltage regulator?

Sorry for newb questions, this part I really want to make sure I don't mess up...

Many thanks

Yes the transformer is suitable for use in the UK. Connect the brown wire on your transformer to L' (switched live) on your IEC. Connect blue wire on your transformer to N' (switched neutral) on your IEC. Connect PE' (Protective Earth) on your IEC to your metal chassis with a thick piece of yellow/green striped wire (via a dedicated nut and bolt separate from anything used to close the chassis, and make sure you scrape the paint or powder coating off the metal work so you get a good contact, and be sure to also use locking washers too so that it cannot accidentally work loose.)

Connect grey to violet via a connector (make sure they do not contact anything else)

Connect red to orange on your transformer and connect both of these to 0V on your CRC board (middle pin), and to your protective earth on the chassis, and to pin 1 of your input XLR's. [if you're using shielded input cables from the XLR's don't connect up the shield at the SSL PCB end or you'll get a ground loop) Some people might have a different preferred routing for chassis protective earth versus signal earth but the main thing is to stay safe, and to avoid hum loops.

Connect black on your transformer to one of the outer input pins on your CRC board.
Connect yellow on your transformer to other outer input pin on your CRC board.

A 1A time delay fuse should be fine.

This is DIY so you need to be prepared to do some work yourself. The output of the CRC board (3 pin header) goes to the "External AC In" 3 pin header of the gssl pcb. But the CRC board is already rectified (DC). The middle pin of the 3 pin header is 0V on both boards. If you're not confident, you can mount a bridge rectifier on the gssl pcb, so even if you connect up the wires the wrong way you won't harm the gssl (provided you've bought the recommended bridge rectifier). If you're confident you can work out which output pin is +ve on the CRC (nearest C5) and which is -ve (nearest C6) and simply replace the bridge rectifier on the main gssl psb with appropriate wire links (or 10R resistors if you've fitted the 1000u caps) to route the +ve supply to the 7815 and the -ve supply to the 7915. Wire links/resistors are the better way, but if you're not sure fit the rectifier..... You might also have to put in some other wire links for the 10R resistors for the 12V supply if you haven't fitted these. Of course you can always power up without any IC's or VCA's fitted, and check whether the voltages are stable and of correct polarity first before fitting them.

 

[Harpo]

I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

Difference in level of +/-1dB is most likely caused by parts (resistors/VCAs) tolerances.
Except an UFO dropped on your unit and now every resistor is blinking morse codes for whatever alien reason, probably every GSSL related question was answered numerous times.
This thread could be 250 pages smaller if builders would read. Maybe try the search button.
My last answer to overall level imbalance was 8 pages ago. I stopped counting the others. If imbalance is happening when compressing, easiest fix might be to either tweak the 1K/120R voltage divider in front of the DBX202C substitution circuit or the 1K resistors at the audio-VCAs control port.

 

[spudstyle]

This thread could be 250 pages smaller if builders would read. Maybe try the search button.

Yes it's true but, like me, if you are bad in english (and in electronic), it's not easy to do a good search. Before asking a question, I try to use search... But a bad search cause I don't use good words.

I tried search button for my noise problem posted yesterday but no results and no answer
I'll try to make crc board but I think the problem is other thing because I don't have noise on my right channel.

 

[Arnoid]

I also noticed that from the compressed output signal the left output has 1db more then the right output ??
What could be the problem of this ? The outputs are not symmetric ? 

Somebody can help me out plz ?

Difference in level of +/-1dB is most likely caused by parts (resistors/VCAs) tolerances.
Except an UFO dropped on your unit and now every resistor is blinking morse codes for whatever alien reason, probably every GSSL related question was answered numerous times.
This thread could be 250 pages smaller if builders would read. Maybe try the search button.
My last answer to overall level imbalance was 8 pages ago. I stopped counting the others. If imbalance is happening when compressing, easiest fix might be to either tweak the 1K/120R voltage divider in front of the DBX202C substitution circuit or the 1K resistors at the audio-VCAs control port.

thx 
Sorry... I did try the search button but I used the wrong words :

 

[Harpo]

Ok, now my compressor is working but on my left channel, I got a ground noise. The right channel is ok, very low noise. My kit is from PCBGrinder and a capacitor was missing in the package (cause the BOM say 9x100pf and really need 10). I find another capacitor at home that is 100pf but not the same size cause it's a 500v (see attached picture). So this capacitor can be the problem ? In this case, what type of capacitor I need ? 50v, 100v ? I don't have the reference of PCBgrinder kit capacitor.
Thanks for your help.

Your 100pF cap is OK. You won't find a cap with this dialectric where voltage rating in this spot will be your concern.
Some other parts in the blurry area of your pic are at least questionable, IE without trimmer fitted, ment for a different type of VCA, some resistors are one side connected only, doing nothing. The pretrimmed THAT2180 VCAs prefer pin4 unconnected, so you might pull out the 47R and 68Rs connecting to THAT2180 pin4. Other members snipped pin 4 off or bent this pin sideways, so it didn't make connection to pcb (just leaving the 47R or 68R out seems easier/cheaper, but YMMV). You might pull out the 10Ks between VCA pins3/5 as well, once ment for a different type of VCA.
Whatever your 'noise' might be, this will more likely be either hum at double mains frequency, caused by ground loop(s), hum at mains frequency, induced by your mains transformer or hiss, caused by a missing ground connection. From your pic, seeing the molex center pin connected, this might be caused by the 1st case. XLRs pin1 connect to chassis in the shortest possible way and using seperate wires instead of a mic cable (with shield only one side connected), you want the wires connecting between XLR-pin2/3 and pcb twisted together, so the differential receiver has a better chance to cancel out induced garbage. Using metal/conducting standoffs in the wrong spot might be another reason.
Just my 2ct.

 

[thepraqtice]

Thanks MeToo2 thats exactly what I needed to know. Great help!

I'll post back soon with some progress hopefully.