Rob,
The Oppo universal players have "bass management" - i.e., a built-in crossover, and an RCA line-level connection for a powered subwoofer. With Oppo's bass management, the low frequencies are off-loaded from the main amp and speakers, which differs from a "double bass" implementation of a subwoofer (which is common) wherein low frequencies are sent to both the main speakers and the sub. The low frequencies eat up a lot of power. With the Oppo's implementation, the main amp and speakers are less likely to overload (and sound congested or distorted) during fff passages of music. The last 4 generations of Oppo players have bass management (the newer models have adjustments for the crossover): UDP-205, BDP-105, BDP-95, and DV-980H. If you’re on a limited budget, the DV-980H plays SACD, CD, and DVD, and have been selling for $50 - $100 on eBay. The newer models play downloaded FLAC files, Blu-ray (audio and video), and the newest model plays UHD discs.
I've chosen the high-end Oppo products because they are "universal players", and have a high-quality DAC built-in. I have all of the Oppo units listed above installed in different stereo hi-fi systems. The Oppo units listed above all have variable output (i.e., volume control on remote) enabling them to be connected directly to a tube power amp (i.e., no pre-amp) – assuming good system synergy. And, for a vintage integrated amp, they add the convenience of remote volume control.
If you don’t currently have the ability to play SACDs or downloaded hi-res (24bit/96kHz) FLAC recordings, you might consider this in your quest for high quality reproduced sound. Your hi-fi system will never sound better than the quality of the recordings.
I’m a big fan of tube amps (I own more than 2 dozen, including several Fisher). And good quality Kilpsch speakers are capable of excellent sound when mated with the right amp. FWIW, I’m a fan of Klipsch RF-7 II. (You'd have to find used RF-7 to get close to your budget, but you'd have a life-time investment.) With RF-7 (I or II) and >20 wpc tube amp, you won’t really need a subwoofer (saving that cost), unless you listen to pipe organ music, or you want to feel the impact of a bass drum. With an Oppo player, you have the option of adding a sub later, just by changing the software settings in the Oppo. (I can provide the settings to implement 2.1 for each model.)
Hope this helps.