Alexandru, there's a great debate way back in the early days of the 990 forum about this very subject in which one very knowledgeable contributor (soundhound) presented much the same argument that you do: a more complex signal path is inevitable with balanced connections, so he didn't recommend using balanced connections unless you need them for the purpose that they are intended to address (noise/interference from outside sources over long cabling runs).

SP72, a transformer is usually found in very high-end or professional gear, for it's way more expensive than an op amp. Not to mention 7 of them. I stronly doubt power amps one might hook a 990 to will have them, for those players are in a different league. But, nevertheless, your point is correct. It doesn't HAVE to always be two active components in the signal path.

Gonk, I can only feel honored for being mentioned in the same phrase with a very knowledgeable contributor, which by no means I am. My hi-fi experience is mostly theoretical (I'm an engineer), but I don't own high-end gear.

Please forgive my newness to the site. So bottom line, is there any audio advantage for one model (1070) over the other (970/7075 amp combo). I am ready to purchase one or the other and like the idea of the separates for future upgrades, but is it worth the extra $ 300. Is there more power with the combo? Opinions appreciated!

Welcome to the site, Dave!

The 7075 will offer almost no difference in rated power over the 1070's amp section - 10W or so isn't going to be audible in and of itself. The 7075 will offer an amp section physically isolated from the more sensitive pre-amp electronics, a larger power supply (for more ably handling transients produced by very dynamic music and movie soundtracks), and a potentially easier upgrade path down the road (keep the amp, replace the "brains"). Plus, if you have any need for a subwoofer, you can get an LFM-2 for free at the moment with the 970/7075 combo.