The Soundcraft 600’s padding of line‑level sources so they can be run through the mic amps, as indicated in this excerpt from the manual’s block diagram, is a common and pragmatic arrangement — and really not as big a ‘problem’ as some purists may suggest!
I’m restoring an old Soundcraft 600 mixer so have been reading up on it. It seems that for line‑level signals it just pads them down and uses the mic amps. I’ve read some disparaging opinions about this way of doing things on the Internet, with purists suggesting it’s better to have a dedicated line amp, but I also trust that the Soundcraft designers designed it well! Does it really make a difference?
SOS Forum post
SOS Technical Editor Hugh Robjohns replies: The designers did a good job: the Soundcraft 600 was a good‑sounding, cost‑effective console that more than one SOS editor has enjoyed owning and using! I’m sure you’ve downloaded the manual, which is still available on Soundcraft’s website, and this confirms that the line inputs are padded (30dB) to a high mic level and routed through the mic preamps. It’s also true that where cost and size are not issues a separate line amp offers marginal technical and operational benefits.
There will be some other compromises in the console for the same reasons but, as I say, this is a good, well‑designed console.
In the real world, though, cost and size matter to customers and manufacturers, so compromises are made. This particular approach is an extremely common and pragmatic arrangement, with negligible technical compromise: a high‑end audio analyser might detect fractionally higher noise and THD than in a dedicated line amp but your ears won’t, so it makes no practical difference in normal applications. There will be some other compromises in the console for the same reasons but, as I say, this is a good, well‑designed console; if you prefer the purist approach, you’d be looking at paying rather more for brands like Neve or SSL.