My 'Quad' room is 19x21' with a ceiling that rises from 6-1/2' to 12'. I listen to large-scale classical and film music and movies too, as the 989s are the LRs, but not nearly as loudly as I hear some of my friends play their audio systems. I heard the 989s demonstrated driven by a pair of Manley parallel-SET amps that the fellow said had about 25 Watts of power; they sounded jaw-droppingly excellent.
I drove them first with a tubed 70WPC c-j Premier Eleven-A (from the default 4-Ohm tap) and had plenty of power and quality. Then I got a pair of Chinese-manufactured unknown-brand 100Watt monoamps that used 4 KT88s and also had a triode switch. I'm now driving them in triode with what I suppose is about 40 Watts per channel. I've never overdriven them (ie caused the speakers to 'clamp' their input signals), and I never feel that I don't have enough power or dynamic range.
It sounds to me as if you need something like 50 - 100 Watts of tubed power, unless you listen at LOTS higher levels than I. I'd try a c-j Premier Eleven-A; there usually is at least one here on A-goN for about $1600. If the Eleven has enough quality but not enough power, you have at least 2 options, the easiest one of which IMO is to buy another Eleven and run both in mono. I think you'll NOT find a more-affordable option for c. 150WPC of very-high-quality tubed power. (FULL DISCLOSURE here--I'll have my 2nd Eleven for sale soon. E-mail me if you're interested.)
BTW, the one clear aural advantage of solidstate amps, their very-high bass-damping factor, doesn't apply here, as a 'stat's diafram is NOT 'controlled' by the amp's output stage the way cones are.
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I drove them first with a tubed 70WPC c-j Premier Eleven-A (from the default 4-Ohm tap) and had plenty of power and quality. Then I got a pair of Chinese-manufactured unknown-brand 100Watt monoamps that used 4 KT88s and also had a triode switch. I'm now driving them in triode with what I suppose is about 40 Watts per channel. I've never overdriven them (ie caused the speakers to 'clamp' their input signals), and I never feel that I don't have enough power or dynamic range.
It sounds to me as if you need something like 50 - 100 Watts of tubed power, unless you listen at LOTS higher levels than I. I'd try a c-j Premier Eleven-A; there usually is at least one here on A-goN for about $1600. If the Eleven has enough quality but not enough power, you have at least 2 options, the easiest one of which IMO is to buy another Eleven and run both in mono. I think you'll NOT find a more-affordable option for c. 150WPC of very-high-quality tubed power. (FULL DISCLOSURE here--I'll have my 2nd Eleven for sale soon. E-mail me if you're interested.)
BTW, the one clear aural advantage of solidstate amps, their very-high bass-damping factor, doesn't apply here, as a 'stat's diafram is NOT 'controlled' by the amp's output stage the way cones are.
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