My specified three-digit op-amp count should perhaps be clarified. I was guessing the number of audio-path op-amps in a round trip from mic pre to tape, then back from tape to the mix bus...
I've just pulled a late 1980's module onto my knee, to make an accurate count:
Twelve op-amps on the input card: 9 of which are signal-path 5534s
Two 5534s on the dynamics card (and twenty non-audio path op-amps in the DC and metering sections)
Thirteen 5534s on the EQ card.
Two 5534s on the fader card. (and a few other non-audio op-amps)
Fifteen 5534s on the channel amplifier card.
That's a total of forty-one 5534s per channel (and about thirty non-signal path op-amps).
Two trips through that lot is about eighty 5534s, then the center section of course adds a good chunk more. -In the case of a 6000 (E or G-series), the A/B/C mix bus summing setction (the SL651) and then the master program section, compressor/master fader, signal output buffers and distribution etc.
I'd say that probably takes it to well over a hundred on both the 4000 and 6000 series, but if you're just going 'once through' from input direct to the stereo bus, that drops to sixty or so.
If you switch out the EQ and filters, you lose plenty of op-amps, and obviously bypass the record bus summing stages etc.
In fact, the I/O module (when used with just a mic input, with no EQ, no dynamics, no insert, going straight to the mix bus) only has about four 5534s in the signal path... but there's really no reducing what happens at the center section! -Does the module sound significantly different if the EQ (set flat) gets switched out?
I'd really like to take a Neve or an API module, power it and resistively feed the stereo outputs onto the mix bus, then see if it has some of that classic SSL 'softness... -It wouldn't surprise me if it did...
So did I just undermine my own suppositions? -I suspect that I did.
But until we know, we may never know... :wink:
Keith