Originally Posted by Virtalahde
Yeah, I know. When I had my GSSL build with some THAT or DBX VCA inside it, it did have something wrong with it when you tried to make up the gain. I've also installed a similar compressor inside a console, and one of the mixing guys said he's noticing they sound go "grey".
I'll have to test this further, but the all-in-one chip in these things seems to sound better. Although, I'm going to hook up a simple low/high EQ with gain make-up (Forssell 993) at the end of the chain, which might just as well be the final word in gain for me.
Could those VCAs be 2150s? I had 32 channels of mix automation using those things... It's like the new VCAs are from a different universe!
I have very similar sound/performance to the P3S using seperate VCAs and RMS detectors but the I/O in that product (P4DMS) is so different that the box as a whole does sound very different. But, I have none of the issues there that I have had with "vintage" VCAs. If I were to swap in 2150s or older that grainy character might resurface.
I spent 3 months comparing VCAs in a minimal test bed... Just VCA and the components needed to interface with the outside world, and the results were a real eye opener! Nuff said on that particular subject, exept that the VCA is not where you want to get character!!!!
And, you are correct. The all in one "Analog Engine" does sound very good indeed compared against anything currently available.
I have also played with external gain and had good results there. I have used Ampex 351, simple op amp stages using Scott Liebers' excellent 2520, AD797 based solutions and Wayne Kirkwood's Class A stage.
All obviously different in character, all desirable.
I have also used the onboard, VCA derived gain built into the P3S and P3S ME and haven't noticed any detrimental effect. Very transparent gain there.
When I do THD plots, I test the audio path with no GR or gain and see THD figures as low as 0.0044% THD. This test is mainly to confirm that the design is sound more than a spec that suggests any tonality that the P3S has. It does not say anything about the sweet silky character of the box. We have to keep in mind that compression, or any other modulation of audio IS distortion from one perspective or another.
One thing I would really like to have in my studio would be a Stereo Kirkwood Class A line amp driving some transformers in a rack box for just this purpose... I think that and my dual 351 line amp would be the 2 most "go to" external gain stages, at least for me.