Amp pairing for Sierra 2 bookshelves and Vtf-1 Mk2

That's an interesting suggestion. Sorry for my ignorance but what exactly would the sys do for the sound quality? Also what would you suggest for power amps?

Its not what the Sys will do, its what it won't to. To make a good sounding active line stage is difficult and costs a lot more money than what your budget allows. The reason for the high cost is due to the fact that the lower the signal voltage, the more sensitive it is to changes, and that makes it more difficult and costly to work with.

So if you're building a system and have limited funds, a trick to get around the low cost active line stage problem, is to just not use one. Use a passive instead. Its basically an unpowered volume control with 2 inputs (The Sys). All it does is control volume when placed between your dac and amp. You don't plug it in because it doesn't have active circuitry. The reason I mention the Sys, is that its made by the same company that makes your dac and I'm sure that both pieces are designed to compliment each other.

There is one thing I want to be clear on. I'm not saying you can't get a good sounding integrated amp in your price range. You can. My suggestion is meant to take the sound quality of a good amp to the next level.

It wouldn't be a bad idea to call the people that makes your dac and ask them about the combo. Aside from naming their company, they have a very good reputation and know what they're doing.

I had the Sierra-2's in my office with a Rega Brio-r. It was a very musical combo I used for over a year. Hours and hours a day, non-fatiguing.

I also owned a Mira 3 that I used with the same monitors when they were Sierra-1's (before the upgrade). I prefer the Brio-r and the Mira 3's are starting to show their age in the marketplace with the output transistors going bad.

So in that sense do you mean for me to forgo a new amp entirely and get the sys to bypass the preamp in the yamaha or to get a good power amp (which I am certainly open to suggestions on) and connect it via the sys?

I agree with zd. Pairing a passive preamp with an amp could give you much better results in your price range. I'd seriouisly look into offerings from class d audio among others.