Some observations on different vca's/op-amps with G-SSL . .

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strangeandbouncy

Well-known member
Joined
Aug 8, 2004
Messages
2,112
Location
West Sussex. UK
Dear All,

Yesterday I conducted some(not very scientific) experiments with my 2 G-SSL's. One has 2151's, the other has dbx 2001's. I am not much of a fan of "A/Bing" since often all you can hear is the switching click . . . Now I have long prefered the 2001 version, finding it smoother, warmer and sweeter. I set up a compressor and after half an hour swapped it for the other. Showing my work partner how to change them, we continued, with him changing, so as how I couldn't see. I also asked him to throw me some "placebo" changes when he just pretended. Each time I could easily spot the compressor! Quite surprising! Even more suprising was the fact that I actually PREFER the 2151's on my drum sub-bus. More punchy, snappy, and aggressive, especially in the mid-range.
A couple of months ago, I accidently plugged my 2001 G-SSL over the lead vocal in a mix, liked it loads, and have used it more and more ever since. Now it is pretty much my first choice every time! Not so the 2151 G-SSL, which although making the vocal "sit" in the same way is "clacky"er and harder. I also tried to make the same comparison with the Quad Comp on our SSL, but comparisons are hard, since the levels in and out are much less than on the G-SSL. Not sure why. This sounds more like the 2151's. i am hoping to purchase some 202c's and some 2181's to try out soon.
I then tried changing the 5534an's for Fabio's 2@5@2%0bc's soldered onto some 8 way dil sockets. WOW! I have read some erudite folk round here say that it won't make a lot of difference. All I can say is try it! Depends on the material, and yet again, vocal is much smoother, warmer, sweeter, detailed, "Focused", etc i still prefer the 5534an's on the 2151 G-SSL over the drum-bus, for the same reasons as I prefer the 2151's there, ie punchier, more "smack". Over the mix, 2520bc is awesome. much more detail! Now I tried 2x2520;s lashed onto a dil socket to replace 5532's. Squeels like a pig! :? Loadsa RF . . . .damn! try as I might, no joy. i'll have to try again tomorrow with a clean head! Anyway I took the oportunity to try some OP275's in place of the 5532's. SAme Deal Again! Much smoother on the 2001's seems like there is more "extension" in the h.f. on a vocal, but I prefer "old clunky" on the drums.
the final experiment was to try to hear the difference in the sound running balanced/un-balanced. With both types of vca and output op-amps, I much prefer the sound running un-balanced! Maybe I just like the sound of the vca's running hotter? or perhaps the output is more symetrical? the negative leg is going through another op-amp than the positive. Who knows!

Anyway, i hope to be able to report a G-SSL with a completely discrete/Class A signal path, not just a partial one! i can't wait.

In the mean time PLEASE can someone sell me some more dbx2001's - even 1 will do . . .

All the best,

ANdyP
 
Sad to report that I have had to put the 5534's back, due to intermittant rf and squeeling in one channel only. Perhaps the flying leads are too long? goes away as soon as I touch it . . . I am thinking of building the input and output DOA's on perf board with all the relevant resistors etc close at hand . . . . Anyone any other suggestions? more decoupling caps perhaps?

:sad:

ANdyP


p.s. - it still sounds GREAT with 5534;s!
 
hehehe sorry dude - I don't have any!!! but if I ever hear or see of any around I'll point them in your direction.

Sorry to hear about the RF probs - I reckon that could be sorted with this multi-board layout thing I've got on my mind...am pleased that you had positive results with the discretes though - its very encouraging about the whole thing.

Tom
 
Aw, shucks, you old tease . . . .


never mind! i had no joy with the output - just squeeled like a pig. Hopefully, it can be solved with a better layout. Pehaps it is a candidate for the gainbloak? or sumfink . . . I am not quite sure, so please forgive me if i am mistaken ,but i am not absolutely sure that Jakob's diagram is correct as to which half of which 5532 is doing what. i am probably wrong, but who knows. Tomorrow is another (log!) day, so i shall try to work it out to alleviate da boredom. . .

I do have to wax lyrical about the Fabio2@5@2@0 as an input buffer. . . .


ANdyP
 
Note that transistor tolerances in the 2001 might leave something to be desired since these are 1970's ish products. In other words, if you get a bunch of 2001's from Scenaria, they might vary a bit as far as performance, noise, thermal, all that good stuff. I can't say for sure as I still have to build my boards up.
 

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