GSSL HELP THREAD!!!

[ReggieReddog]

[quote author="Sender"] The cap that is to the left of the aforementioned resistor, is that another 0.1 uF cap? [/quote]


Yepper. You got it.



And hey guess what!! I just got mine working and it sounds great! I'll post some pictures when I get a chance. Thanks to everyone who helped my dumb a$$.

 

[matta]

Hey Guys,

I?m about to order a Torrid for my GSSL Comp and according to the SSL PDF a
4.5VA is what is required for a single SSL Comp, so is it safe to assume a
15VA is MORE than sufficient. RE the secondary voltages, would you
recommend a 18V over a 15V, there is no difference in cost, so I can get
either or.

Thanks

Matt

 

[gyraf]

..go with 2x15V 15VA - that allows for juice for the meter light as well..

 

[matta]

Thanks Jakob :thumb:

Will do... looking forward to boxing this unit up, it work so well, I've just not had the time to rack it :sad:

Cheers

Matt

 

[Luny Tune]

Another one done today!:grin:

I turned it on.
Found that the threshold pot wasn't active and that only the 2:1 Ratio seemed to allow for compression. Furthermore even the weakest signal created heavey compression. Everything thing else worked fine.

I searched this thread and found out where to look. Couldn't find any solder bridges but scratched acouple of places where I was not 100% sure.

That was it! Apparently there was a solder bridge somewhere in the Sidechain section where I "safety scratched".

I fired up again, and it absolutely ROCKS!! Wow!! What a compressor!

I'm amazed at how tight it holds everything together and how transparent it still sounds. What a design!:thumb:

I've already mixed my first song with it now only a few hours after it's done.

I'd like to thank first and foremost Gustav for assisting so much with both getting all the parts and much help, those who helped me with the few questions I had, and special thanks to Jakob for helping and also for making it available in the first place.

This was my first DIY project and I feel very lucky that it went so smoothly. I can't wait till the next project.:razz: It'll probably be another one of these first but then on to other "stuff".

 

[gyraf]

Well done, Luny Tune!

:thumb:

Jakob E.

 

[Soeren_DK]

The TYCO knobs for the original GYRAf SSL... Where to buy?

 

[Greg]

I buy them from Newark here in the states... they're the PKES series.

 

[gyraf]

Newark-through-Farnell in Denmark..

 

[bpatural]

Hey guys I've searched around but haven't found an answer to my two problems I seem to have left. Other than these the compressor seems to be working fine although my meter won't be in til monday. First off, the auto release seems to be acting a little funny. When I bypass the compressor it takes about 1 to 2 seconds for the gain to ramp up back to normal level. Also, the output seems to be 6 db too hot, even in bypass. I know I Can fix this with different resistors but I'm not sure why it's happening. My friend who built one of these things actually had his output coming out too low at first. Any ideas? This is my first big electronics project.

 

[gyraf]

Hi bpatural - your questions have been answered before on several occations..

 

[ReggieReddog]

I found this very helpful: http://groupdiy.silentarts.net/martthie_08/gssl/calibration.html

Although, I think he had the resistors for the meter adjustment backwards.

 

[bpatural]

Thanks Reggie. Forgive me Gyraf. I looked as extensively as I could. I replaced the 15K's with 27 and that improved the output gain althoug it's still a little hot. I seem to have a bigger problem now though. I'm getting some hard clipping and ring modulation at the tip of the TLO74. some distortion seems to come into the signal ONLY in bypass mode. I replaced the chip but still the same problem. As I turn the threshold control IN BYPASS, it seems to add distortion really low down in the signal. I checked my solder joints 3 times and they all seem to be good. Any ideas? The unit appears to be compressing normally when in, although I know it's not yet right because of the ring modulation.

 

[bpatural]

Just found out that this cross talk and interaction with the threshold knob seems to be eliminated if I re-attatch the jumper on the make up bypass. Any ideas?

 

[deveng]

Gentlemen,

I'm currently having a front panel made afor an SSL style compressor nd I'm trying to avoid an expensive call to Sifam from the U.S.!
Does anyone know the correct panel cutout dimensions for the Sifam Type 14 PPM meter as used in the original SSL (and Neve) compressors? I have 2 Sifam documents, one for the Sifam PPM type 14 and the Director Type 14. The cutout for te Sifam PPM type 14 shows a 39.5mm hole with 2 mounting stud holes 3mm on a 44.5 mm diameter at 45 degress. The cutout for the Director Type 14 is a 39.3mm hole, 2 2.4mm mounting stud holes on a 44.4mm diameter.

The difference is only at most .007" for any of these (other than the mounting stud holes) but of course I want the meter to fit perfectly. I believe the correct meter is the PPM type 14 1ma FSD (and not the Director Type 14). But, I want to make sure I have the right cutout for this meter!

Can anyone help on this one?

Thanks,
Jeff

 

[Luny Tune]

I'm currently mixing a hardrock album with the SSL comp across the mix.

I have a bit of a noise problem on my desk, a Soundtracs MIDI PC 24. It's not a lot but with a lot of new equipment in the studio recently I need to go over everything and ground and balance it all properly. What I do in the meantime is to take down the masterfader a bit and hit the mix buss a bit harder that suppresses some noise and it works just fine. The mixes sound great and the GSSL squeezes like the thighs on a red head I once new. It's all cool! BUT I discovered that when I'm compressing and turning up gain makeup I reach a point where it just won't get louder. On the meter that is. It's like a brickwall limiter or a soft-limiter where you can push it up to give it more loudness.
My question is: Is there a limiting function after the gain makeup? Or is it just me hitting the return of my insert point too hard?
I would think that it's me overloading the return of the insert point, but it doesn't create distortion, it just sounds like it's limiting the signal. And actually doing the job quite well...! That's why I'm asking...

If it IS the returns that are overloaded, could it be that there's a limiting function there?? Maybe it's intentionally in the design because there's no overload indication otherwise at that specifik point. Or what?

 

[deveng]

Diyr's

Just in case anyone else has this issue in the future, I made the call to Sifam. The information I recieved is that the 39.3mm with two 2.4mm mounting stud holes on a 44.4mm diameter at 45 degrees is the correct panel cutout for the PPM Type 14 meter. I also found out the that the "Director" PPM type 14 and the Sifam PPM type 14 are the same meter.

For those interested, I have designed my own PCB for a SSL style compressor. It operates as dual mono or stereo. I made some initial tests using the the Rightmark Audio analyzer through an RME Multiface. The results were good.

Freq. Response: -0.5dB @10Hz and -2.5@ 30kHz
Noise Level, dB(A): -105.2
Dynamic Range, dB(A): 105
THD %: 0.052
IMD + Noise %: .419

These were all taken with the compressor "in", 2:1 ratio, 5dB of gain reduction and 5dB of makeup gain. Not much use to me to test in the bypass mode! I hope to test again using the Audio Precision Test set to get rock solid measurments and also get rid of the A weighting. The only one I'm concerned about is the IMD. Not sure what it should be using THAT 2151 VCA's and 5534AN input, 5532AN output opamps. In my listening tests the unit sounded very good.

I also designed a hearty power supply PCB to go along with this device. All works perfectly (so far). Once I get the panel completed I'll post some pics.



Regards,
Jeff

 

[deveng]

Diyr's

I just recalled that I have not adjusted the symetry pots for the 2151's! This may explain at least some of the distortion. I built the circuit boards and didn't touch the pots and I have no idea where they're set to. So, I'll give a try at adjusting to see if the THD goes down a bit. This weekend!

Regards,
Jeff

 

[csonics]

Yeah, so I just finished my gssl board, got all connections together, plug in a signal and all I get is a nice distorted farty noise with a litte bit of signal. I get this on both channels! I sounds like it gets more distorted and farty when it compresses more!

I got nothin! Where do I start? Anybody got any suggestions??

Thanks,

Csonics

 

[Luny Tune]

Have you checked for solder bridges and orientation of components? And double checked?

If memory serves, there was already someone with a similar problem earlier in this thread. Could have been something with VCAs with wrong orientation...I'm not sure....but check the thread...

I'm a novice myself so I won't even attempt to help you further than that, but I'm sure that's the first thing any of the experienced guys will ask you. So make sure that's done and then post if there's still something wrong with a remark that you did double check the above first. That way they can skip that obvious first somewhere to look and dig into it if the problem is more serious than that.