The impedance curve for the Matrix 800 that is shown in Figure 1 of Stereophile’s measurements indicates an impedance in the vicinity of 4 ohms in much of the bass region, as I mentioned previously, and more than 10 ohms at almost all frequencies above 1 kHz. That strongly suggests that the speaker is intended for use with amplifiers having low output impedances, and correspondingly having relatively high damping factors. Which disqualifies many tube amps as being suitable matches, regardless of how powerful they are. B&W’s recommended range of amplifier power, 150 to 800 watts, further reinforces a conclusion that the speakers were designed with solid state amplification in mind. (Solid state amps almost always have very low output impedances and relatively high damping factors, those two terms being inversely proportional).
The likely result of driving speakers having this kind of impedance characteristic with an amp having a highish output impedance/low damping factor would be weak bass, precisely what the OP wants to avoid.
While as many here realize I have been a great supporter of Ralph/Atmasphere and his products and his many contributions to this forum, the 2.3 ohm output impedance of the Atma-Sphere MA-1 makes them a non-starter for use with this particular speaker, IMO. Certainly without using the amps in conjunction with a pair of Zero autoformers, and very possibly even with them. And I’m doubtful about the more powerful MA-2 as well, with its 1.75 ohm output impedance.
I’m pretty certain that the CAT JL2 that was suggested, which I see has a specified output impedance of 0.7 ohms, would be a suitable match. As would some or all of the larger ARC amps that have been referred to. Not sure about VTL or CJ.
Regards,
-- Al
The likely result of driving speakers having this kind of impedance characteristic with an amp having a highish output impedance/low damping factor would be weak bass, precisely what the OP wants to avoid.
While as many here realize I have been a great supporter of Ralph/Atmasphere and his products and his many contributions to this forum, the 2.3 ohm output impedance of the Atma-Sphere MA-1 makes them a non-starter for use with this particular speaker, IMO. Certainly without using the amps in conjunction with a pair of Zero autoformers, and very possibly even with them. And I’m doubtful about the more powerful MA-2 as well, with its 1.75 ohm output impedance.
I’m pretty certain that the CAT JL2 that was suggested, which I see has a specified output impedance of 0.7 ohms, would be a suitable match. As would some or all of the larger ARC amps that have been referred to. Not sure about VTL or CJ.
Regards,
-- Al