Originally Posted by ianfoster
So effectively there's no reason to ever change the input gain value for instrument channels?
I've heard from some folks that they have built combinators where the last device doesn't have a volume control (Saturation Knob is one example). They have preferred to use the Input Gain knob to trim levels instead of adding a line mixer. But my reasoning still stands: if you use that Combinator again you'll have to trim it's gain in the SSL again - why not do it once and be done? Also, the level of the patch will depend on how many notes you're playing and the settings of the patch - change these and the level will change. So you need to keep an eye on these things, and for some the Input Gain is more accessible, for others the Instrument Volume is more accessible. Sonically it really doesn't matter, so that's why I mention workflow as the decision maker in this case.
The original SSLs had an Input Trim because the signal was coming from tape in those days, and that was the ONLY place you could trim it's level (besides inserting a rack device and using that for gain - but you had a limited number of rack devices…). So it was used more in those cases, but the audio rules still applied. In other words, if you adjusted the gain on the input and you had already set a compressor for that channel, you'd need to check the compressor settings to adjust for the new input level. :-)