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The amplifier is designed for fairly unusual applications:
1) You can drive it directly with a line source such as a preamp.
Using this amplifier presupposes that you have a preamplifier or other source with
adequate voltage and/or loudspeakers sufficiently sensitive to be able to work with
the voltage and gain you have.
You would think offhand that this might be a real problem, but it is my experience
that this is often not the case.
First, you will find that the more sensitive drivers deliver good volume levels at
quite low wattage. My Lowther DX55's (93 dB/watt) mounted in Alerion
enclosures adequately fill my 11,000 cubic foot listening room with about 5 volts
(the equivalent of a 4 watt amplifier). I can achieve good levels with headroom to
spare with my phono stage or DAC feeding an X1 preamp, which has a maximum
of 14 dB gain.
If I lived in an apartment, I could get complaints from my neighbors.
Thanks to the dutiful efforts of John Atkinson at Stereophile, I have been able to
examine the maximum gain and output voltage of the tube and solid state
preamps he has measured over the last 20 years or so (
www.stereophile.com
).
Virtually all active line stages achieve adequate gain and voltage swing to drive
the above combination. Basically you need a linestage with about 12+ dB gain
and 10+ volt maximum output.
This includes tube products from VTL, Hovland, ARC, Cary, McIntosh, CJ, EAR,
MF, BAT, Lamm, and Rogue. It includes solid state preamps from Pass Labs,
Krell, McIntosh, Levinson, Halcro, Naim, Boulder, Ayre, Bryston, Threshold,
McCormack, Linn, Sutherland, and on and on.
If your loudspeaker is less efficient, then you need more gain from your source
and/or more gain and voltage swing from your linestage. As you go in sensitivity
below 87 dB, you will want to consider 100 watt balanced mono-block use, with a
preamp capable of swinging 14 volts per balanced output and having a gain of
20+ dB.
As your loudspeaker increases in sensitivity, you need less gain and voltage
swing.
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