Emotiva has just announced the impressive BasX A11 Eleven channel power amp at the price of $1,299. I believe this is a much needed component, in the world of Atmos/DTS:X. The specs are truly surprising, and Emotiva has always been quite conservative with their power ratings. IOW, their amps provide the power that's stated, if not more.
They provide an array of power specs, which are copied below, and I'd like to dive into them a bit.
First off, this is a large amp, measuring 17" wide, 7 3/4" high, 15 1/2" deep, and weighing 51 lbs.
The specs from their site...
- Power Output (ALL channels driven):
105 watts RMS per channel; 20 Hz – 20 kHz; THD < 0.1%; into 8 Ohms.
140 watts RMS per channel; 1 kHz; THD < 1%; into 4 Ohms. - Power Output (two channels driven):
160 watts RMS per channel; into 8 Ohms.
260 watts RMS per channel; into 4 Ohms. - Power Output (5 channels driven):
145 watts RMS per channel; into 8 Ohms.
200 watts RMS per channel; into 4 Ohms. - Power Output (7 channels driven):
125 watts RMS per channel; into 8 Ohms.
180 watts RMS per channel; into 4 Ohms. - Power Bandwidth (at rated power; 4 Ohm - 8 Ohm load): 20 Hz to 20 kHz (+ / – 0.07 dB)
- Broad Band Frequency Response: 10 Hz to 80 kHz +0/-1.8 dB
- THD + noise: < 0.02% (A-weighted); ref rated power
- Signal to Noise Ratio (8 Ohm load):
> 115 dB; ref rated power; (A-weighted). - Minimum Recommended Load Impedance (per channel): 4 Ohms
(which equals one 4 Ohm load or two paralleled 8 Ohm loads). - Damping Factor (8 Ohm load): > 500.
- Input Sensitivity (for rated power; 8 Ohm load): 1.2 V.
- Gain: 29 dB.
- Input Impedance: 27 kOhms.
I'd like to spell out what some of these specs mean in the real world.
An important one is the Two Channel spec. This shows the maximum output the amp channels are capable of. So, it is capable of outputting up to 160/260 watts (8 Ohm/4 Ohm) to any of the channels. This is important, because most of the channels in surround sound, particularly anything other than the front three, never have much power demand placed on them. Especially overhead channels with Atmos and DTS:X, where home mixes often have little to no actual sound steered to them. When they do, it's mostly higher frequencies, which don't need much power. Since the challenge to all channels driven is the amount of power the amp has coming from the power supply, in the real world there will never be more than three channels outputting the full capability, and the amp will never be strained in all eleven channels at the same time.
The two channel specs need to be considered along with the others, especially the all channel one, which still maintains an impressive 105 watts into 8 Ohm. That does bring us the one non-spec in the entire list, where the 4 Ohm spec is a 1 kHz tone with high distortion. As impressive as this amp is, it's not one to drive a system made up of entirely 4 Ohm speakers in a large room at extremely high levels or with especially inefficient speakers. Having said that, there will never be a situation where all the channels are driven to capacity, for the reasons I've already explained. So, the bottom line is, Unlike any receiver, this amp is absolutely suitable for driving almost any system that has several (or all) 4 Ohm speakers.
I think it's safe to say that in real world conditions, your front three speakers should always be able to receive at least the five channel driven spec of 145/200 watts. There is no receiver in existence which can match that power. In addition, the $1,299 price makes is entirely possible to step down one level in a receiver line, such as from a Denon 6xxx series to 4xxx series and add this amp at roughly the same total cost, for those who want to stick with a receiver as the base of their system. It's just necessary for that receiver to have preamp outputs for all channels.
Common for Emotiva, the BasX A11 is a Class H design. Where Class D is becoming more common, Emotiva seems to prefer to design their amps from the ground up, and a basic reality of Class D amps is the Class D output has to be purchased from one of the handful of companies who specialize in them. Instead, Emotiva prefers traditional Class A/B, and more commonly Class H, which is a variation on Class A/B. In Class H, as opposed to using a linear power supply to power the output, it uses a switch mode power supply which monitors the power demands at a rate of around 200,000 Hz, increasing and decreasing it as needed. This results in efficiency and lower heat generation similar (but not equal) to Class D. With reasonable ventilation, Class H designs should never have heat issues.
What's unusual here is Emotiva has always limited Class H designs to their high power XPA amp lines. All the other BasX amps have always been traditional Class A/B. I suspect Class H doesn't make a lot of sense with amps that aren't several hundred, or even a thousand watts per channel. What is different here is the sheer number of channels, so the potential for total power consumption is rather high, and the Class H design makes sense.
I think this amp is a real winner for more serious home theater owners, who have never quite wanted to go the separates route, as well as for those who were always tempted, but held back my the number and cost of amps needed to build a full blown Atmos/DTS:X system. Combined with a pre/pro like a Marantz AV7706, the BasX A11 can create a better all around option than any top-of-the-line receiver, probably at a lower price.
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