@bestbaker, as mentioned earlier the speakers are spec’d at 87 db/1 watt/1 meter, with an impedance of 4 ohms nominal and 3.2 ohms minimum. A brochure I found at HiFiEngine.com indicates that an input of 8 watts will produce 96 db at 1 meter, which is precisely consistent with the 87 db/1 watt number. I couldn’t find an impedance curve for the speaker, though, which would indicate how its impedance varies over the frequency range.
**If** the 87 db and 96 db specs are accurate (and speaker efficiency and sensitivity specs are often optimistic by a few db) it can be calculated that at a listening distance of say 12 feet in a medium to moderately large size room two such speakers driven by say 50 watts will be capable of generating an SPL at the listening position that is in the mid to upper 90s. That will be enough volume for most listeners with most or all of their recordings, but it will certainly not be enough for some listeners with some recordings. Especially recordings having particularly wide dynamic range (i.e., a large **difference** in volume between the loudest notes and the softest notes), such as many well engineered minimally compressed classical symphonic recordings.
What may be a more significant concern, though, (which Millercarbon alluded to in his post early in this thread) is impedance compatibility. The speakers were presumably designed with the expectation that they would usually be driven with solid state amplification, and solid state amplifiers almost always have output impedances that are a tiny fraction of an ohm. While the output impedance of tube amps varies widely, and can be anywhere from somewhat less than an ohm to several ohms or more. If the impedance of the speaker varies significantly over the frequency range (and it probably does, although as I mentioned I couldn’t find an impedance curve for it), the interaction of that relatively high amplifier output impedance with the speaker’s impedance variations is likely to have unpredictable tonal consequences that were not intended by the designer.
To minimize that you would want to choose a tube amp having relatively low output impedance, which correspondingly means a damping factor which is relatively high (for a tube amp). I would certainly not feel comfortable choosing an amp having a damping factor of less than say 8, and many and probably most tube amps do not meet that requirement.
Makers of tube amps having relatively low output impedance/high damping factors include Audio Research, Music Reference, McIntosh, and possibly various VAC models which provide a 2 ohm output tap. However finding an amp which provides adequate power, low output impedance/relatively high damping factor, high quality sonics, and meets your stated budget, is likely to be a challenge. Personally I would follow the advice of those who recommended staying with solid state.
Regards,
-- Al
