The answer to your question is that we do not provide that specification.
The reason why we don't provide that specification is because it isn't very useful (at least not for an audio amplifier).
The reason why that is true is that the amount of current an amplifier will be asked to deliver depends on the output level and the load.
(And designing an amplifier so that it could deliver massive amounts of current that it will never be asked to deliver has no actual benefit.)
Let's say you have a light bulb rated at "120 watts at 120V".
If you plug that bulb into a 120V 10 amp outlet it will draw 1 amp (120V x 1A = 120W).
And, if you plug that bulb into a 120V 20 amp outlet, it will draw the same 1 amp.
And, if you manage to find a 120V 50 amp outlet, and plug the bulb into that, it will draw THE SAME 1 AMP.
It doesn't matter how much current the circuit COULD deliver because the bulb only REQUIRES 1 amp at 120V.
(It would only matter if the circuit was unable to deliver the 1 amp that the bulb requires... in which case it would fail to light at full power.)
The same situation is true for amplifiers and speakers.
All that basically matters is that an amplifier can deliver the current necessary to run the load (the speaker) at its rated power.
As long as the amplifier can play, at full rated power, into a certain load, without distortion, it is "delivering enough current".
(And there would be no benefit whatsoever if it was "rated" to be able to deliver more current than it needs.)
Now, there is a
very slight "complication" there when it comes to audio gear....
Very few loudspeakers are purely resistive loads.
Almost all loudspeakers have some capacitance, and some inductance, and some mechanical characteristics as well.
Therefore, unlike a light bulb, most speakers have an impedance that varies with frequency, and may drop below its rated impedance at some frequencies.
It is generally agreed that "a well behaved loudspeaker shouldn't drop below 3/4 of its rated impedance"; so 3 Ohms for a" 4 Ohm speaker" and 6 Ohms for "an 8 Ohm speaker".
Some speakers may exceed this a little... but only a few well known "problem speakers" exceed it by much.
So, because of this, a typical amplifier may occasionally be asked to deliver a bit more current than the impedance rating of the speaker might suggest.
All of our amplifiers can in fact deliver significantly more than their "rated current" for short periods of time if called upon to do so.
The XPA HC-1 is a monoblock, so it has one channel of amplification, running from a single dedicated XPA power supply (which is rated to be able to deliver over 2.5 kW).
You can rest assured that there is plenty of current available there if and when it's needed.
But, well, we haven't actually measured it, because the exact number just isn't a big deal.
Also note that, while the XPA HC-1 will cheerfully drive a 2 Ohm load, if you tried to do so at full power, for extended periods of time, it might eventually overheat.
(That's why we rate it for driving normal home loudspeaker 4 Ohm and 8 Ohm loads.)
Now you may have heard that "some difficult to drive speakers require huge amounts of current - and need an amplifier that can deliver it".
This is true to a point....
There are, quite literally, a half dozen speaker models out there whose impedance drops absurdly low at certain frequencies...
One well known "problem electrostatic speaker" has an impedance that drops to about 0.9 Ohms at 20 kHz.
And, yes, this is really unusual, and most normal amplifiers, designed to run normal speakers, will have a problem with it.
(But, if you have one of those few problem speakers, you know who you are, and that you're going to have a limited choice of amplifiers that will run it.)
I should also point out that Magneplanars are NOT one of those unusual speakers that "requires a lot of current".
It is true that Magneplanars are very inefficient, and tend to require a very powerful amplifier in order to sound good, especially at high listening levels.
But, once you meet that requirement, they actually have a rather "benign" impedance, and are not especially difficult to drive at all.
(I assume that whole myth started back when powerful amplifiers were difficult to find.)
For several months, I've been happily using a pair of these amplifiers to power my Ascendo System Zf3 loudspeakers. A dear friend who's been thouroughly impressed by this pairing recently inquired about the HC-1's amp rating (he's currently running a pair of VTV's with his Maggies). Try as might, I haven't found an answer to his question online.
I'd appreciate your help here. Thanks
