I have called Vincent Chen at Emotiva, and spoke with him. Vincent stated that he is not an Engr. so send your technical questions to Lonnie via Email, of which I have done. But no reply in a few days yet.

The XPA-5 is showing a Xformer Size = 1200 VA and many are questioning how EMO could get 200W RMS per Ch. with All Channels Driven (ACD) or 200 x 5 = 1000W, since this amp is a Class A/B design, and in practical design Modern Class AB amplifiers are commonly between 35â€“55% efficient with a theoretical maximum of 78.5%. (per WikiPedia).

I have yet to see or read a Bench Test on the XPA-5, excluding EMO's test data, using the Audio Precision Test Equipment, which I hear is some of the best in Audio for testing, but there are so many specifics that I do not see, such as:

1.) How long was this test performed for in Sec./Min./Hrs./Days or what?

2.) Was a Variac used to hold the input line voltage up to 120Vac to eliminate Line Sag during the test?

3.) Was the 8 Ohm test load a full Resitive or Reactive Load (R/L/C) more like a real speaker?

4.) At 120Vac RMS off of the wall, what magnitude of source current was measured at full power rating? Remembering that most ccts. in residences are 15 Amps max.

Now take our 1800 watt (120V x 15A) max power from the wall, and that would be assuming a PF - Power Factor = 1, which it is most definately is not, and multiply it by our amp efficiency (let's choose 45%) and we get: 1800 x .45 = 810 watts. This is the max power a typical linear A/B amp can deliver on a continuous basis from a 120V, 15A household line - assuming, of course, the amplifier's power supply can consume the entire 1800 watts of power from the line without causing the power transformer to overheat or go into thermal meltdown and likely trip the breaker.

So, maybe the EMO XPA-5 can produce 1000W, or approx. 24% more than 810W for a very short period of time, BUT NOT CONTINUOUSLY ... so it seems to me.

Also, looking at the XPA-1 (500W - 8 Ohms) and XPA-2 (2 x 300W - 8 Ohms), that I believe BOTH of these Amps WOULD BE ABLE to meet their spec. since 500W and 600W is a lot lower than the 810Watts as stated above, and that would allow for the Power Factor worse case even to drop down to 0.74 for the XPA-2, of which we know the PF will be alot higher in most cases (generally between 0.70 - 0.95), so we are on the lower end of the dimensionless value for PF.