GSSL HELP THREAD!!!

[Greg]

[quote author="gyraf"]Are you sure you have the balanced in/out's set correct when measuring with unbalanced test equipment? (-input to ground, output measured between + and -)
[/quote]
I did have the - input to ground, but I was measuring between + and ground on the output. I'm guessing that's it. But I'll check just to be sure. As usual, thanks for the info, Gyraf.

[quote author="gyraf"]
alternatively, try using your unit with a normal balanced input/output under "realistic" conditions and see how levels are..
[/quote]
Will do.

 

[keithcamilleri]

Hi guys...

I was reading up on the original Xlogic, and found that SSL use That2181LA (56 of them) and LT1115 as op amps.

I would like to ask why SSL use 56 of the THATS does it make the sound better? and can the circuit for the clone be altered to use the LT1115 since it is known to be the lowest op-amp available?

Thanks loads...

 

[gyraf]

the 56 VCA's, is that for a complete board?

This compressor is based on our 4000E console, that uses 202-type VCA's. The 2150-mod works well. With 2181lA's, you'll be better off noise and distortion-wise than the original.

There would be very little gained by using different opamps. I've tried that with several types, and the basic sound stays the same. The VCA's contribution to "sound" is much higher than any of the opamp's.

Jakob E.

 

[Greg]

Gyraf:

Just to follow up on my previous post. I was measuring the output wrong. My GSSL is definitely at unity gain, and it behaves fine when operating with other balanced gear. I didn't have a session last night so I was able to use it on a variety of sources that were already recorded (ie kick, snare, drum buss, bass, some vocals). Still haven't tracked with it yet, but that will change after tomorrow.

I really like the auto release (especially for lower frequencies) setting and how the ratio behaves. It's alot easier to hear how the ratio alone effects the sound. If you don't mind explaining, how does the ratio work exactly? I think you mentioned previously it does some type of averaging?

 

[gyraf]

Hi Greg,

Good to hear that your clone is working right.

The ratio control does two things:

First of all, it alters the gain of the rectifier stage - so that the part of the signal that is higher than threshold gets different gains. Second, it adds an offset to the rectified signal, compensating for the lower threshold neded for the same average gain reduction at lower ratios. In this way, the average amount of compression is more or less the same regardless of ratio setting (providing that you feed the unit with about the right levels)

The different ratios sounds different because it reacts on different parts of the input dynamics.

Jakob E.

 

[Svart]

Gyraf and everyone, i completed the population and wiring of two SSL clones over the weekend. I have to thank Gyraf for his work with this compressor because it sounds amazing. In fact, I'm going to have to build a couple more to round out my busses! Now for the bad part. the second clone does not compress at all. the makeup gain is at full and will not attenuate via the pot either. It's like the controls don't work. I populated these boards side by side so each are identical, with identical parts. I haven't had a chance to take a good look at the reason it doesn't work but can anyone lead me in the right direction?

thanks.

 

[gyraf]

Svart,

Check that you have the needed +/-12V voltages present.

Check that you have signal coming to your sidechain, TL074 pin7.

Check that you have DC varying with signal at the output of the sidechain, TL074 pin8

Check that pin 1 and 7 on the TL074 has DC varying with signal level as well as a superimposed DC signal from threshold (TL072 pin1) and makeup (TL072 pin7). These two are your VCA control voltages.

Jakob E.

 

[Svart]

thanks,

I'll probably get to work on it tonight.

now where did everybody get their cases? I was looking at the par-metal ones.

 

[Greg]

[quote author="Svart"]now where did everybody get their cases? I was looking at the par-metal ones.[/quote]

Yes, I bought mine from Par-Metal. But I had to make small notches in the lip Par-Metal puts on their top and bottom panels to make enough space for the B* meter. You can't see the notch b/c it's behind the front panel. I used a Dremel.

 

[kent]

I popped mine in an old ADA chassis that had a lip like the PAR METAL. I figured I would punch the front panel and the box at the same time to put in the "B" meter. I ended up bending both. Hopefully with some paint it will look OK but I learned my lesson.

cheers,
kent

 

[Svart]

just a report on my problems with the #2 ssl.. bad tl074. replaced and all is well! however i noticed something else while experimenting with the controls. when the release is set to longest, there is distortion introduced into the signal. anybody have a clue as to why? I did use 10u instead of 6.8u on the front control board..

 

[gyraf]

Svart,

I'm sure we've had this before:

Are you sure it's set to the longest (auto) release at pos.5, and not to the 6'th position where the switch stops, but where there's no electric release position?

Remember to program the release switch to stop at 5positions..

Jakob E.

 

[Svart]

now that is interesting, because I didn't even remember to check that.. does anybody have a link to some directions for that?

thanks gyraf!

 

[gyraf]

There's a washer with one "teeth" under the nut for mounting the switch, that acts like an end-stop. Take this out (it comes from factory set to "6" on a 2x6-step switch), be sure to turn the switch completely counter-clockwise, insert the washer again, it's teeth at the position marked "5". Now you have a 2x5-pos switch.

Jakob E.

 

[Svart]

thanks!, and one more question i just thought of, how much current do these draw? I was considering putting a pair of these in a 2u rack running from the same tranny and need to know if the one i have will work.

TE62053 from amveco, 1 amp.

and one more.. i swear! (for now)

i don't recall seeing the timings for the attack/release anywhere. are they the same as the rack mount ssl compressor shown on the ssl page?

http://www.solid-state-logic.com/outboard/products/xgseries/

 

[gyraf]

1Amp is enough for two, but I wouldn't recommend this. Take care how you do your grounding anyway..

Yes, the timing is the same - but not for the auto release where you used a different cap (as you mention earlier.

 

[Svart]

thanks gyraf, you're extremely helpful as always!

cheers!

 

[pxpx83]

I just started stuffing my ssl pcbs and I've got a question about a couple resistors. Why is there a * next to the 1k resistors in the left and right VCA? I did a search, but couldn't find any info. I am using the dbx 2151, so should I just solder in a regular 1k resistor?

Thanks!

 

[Svart]

I don't know but i stuffed them anyway and it works fine.. :thumb:

also I ordered my par-metal cases this week. should have everything installed by weekend, however I have some little goodies that i might try to include. maybe some pictures to show later too. now, the meter.. is that .1A to the highest or is it like a 1A with .1 resolution?

thanks

 

[Greg]

[quote author="pxpx83"]I just started stuffing my ssl pcbs and I've got a question about a couple resistors. Why is there a * next to the 1k resistors in the left and right VCA? I did a search, but couldn't find any info. I am using the dbx 2151, so should I just solder in a regular 1k resistor?

Thanks![/quote]


Yes, 1k is suppossed to be there. I think I remember Gyraf saying that he put that there as a reminder to himself for something. The previous statement might be incorrent... regardless, a normal 1k goes in the 1k* in the left and right channel VCAs.