I have a pair of 989s in a room that's about 21 x 19' and about 3200 cubic feet. I've had them only about 2 months. I am NOT a golden-eared audiofile, but I still hear and love the 989s' transparency...'see-thru-edness'...and cohesion, their all-togetherness.
I listen to classical and film music and a little 'lite-duty' jazz. In 2-channel mode my subwoofers don't operate; I drive the 989s full range all the time. I do not listen at very high levels; I've never triggered the 989s' protection circuitry. I drove them initially with a (tubed) c-j Premier Eleven (70WPC) from the (default) 4-Ohm taps. They sounded quite good. I then bought a pair of tubed monoamps that use 4 KT-88s for a claimed 100 Watts (in ultralinear), but I use them switched into triode (from the 8-Ohm tap). I GUESS they have around 40 Watts, but they drive the 989s VERY nicely.
Everything I've read indicates the 989s are NOT hard to drive and that they don't require high current with their nominal-8-Ohm impedance.
If I were looking for poweramps, I'd look for the highest-quality tubed amp I could afford, in the 35- to 100-Watt range. If you prefer solidstate (I have no idea what the YBA Passion is), I'd look in the 75- to 150WPC/8 range. I'd sure stay away from anything that anyone thinks is a tad brite, grainy, gritty, etc.
Pls let us know about what you audition.
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