THX Achromatic Audio Amplifier

[Chris]

I have recently been reading and watching interviews about a new amplifier technology called THX Achromatic Audio Amplifier. I will list some links below. The advantages of this technology is infinitesimally low THD (< -118 dB (< 0.00013%) - Stereo Mode), unheard of high SNR (132 dB A-weighted, Stereo Mode), and high efficiency resulting in a very small size amplifer. The very first commercial amp using THX AAA is the Benchmark AHB2 which is generating some very favorable reviews. The amp costs $3k so it is not inexpensive but neither is it insanely priced compared to other very high-end amps. The advantage I see for Emotiva if they adopted this technology would be much smaller and lighter products plus improved specifications. I understand the licensing would be costly but might be offset by the savings in parts and weight, etc.

I admit I am very partial to Benchmark products since I own a DAC1 and DAC2 HGC.

I also am a bit amused that the look of the AHB2 in black looks a lot like a Hafler amp I built as a kit a few decades ago. According to the inventor, the heat sinks are mostly cosmetic and for the rare times the amp is subjected to torture tests during product reviews! In normal listening they are unnecessary!

-CB

Interview with the inventor of THX Achromatic Audio Amplifier:



Hi Fi News review:
print only

Mixonline review:
Benchmark Media Systems AHB2 Power Amplifier

Enjoy the Music review:
Benchmark Media AHB2 Stereo Power Amplifier This little unit will change the way you look and listen to amplifiers.

[djoel]

I'm all for new tech especially in audio gear.


Djoel

[KeithL]

It looks like a nice amplifier, but don't get too carried away about the "Achromatic" hype. From the technical details, it seems to be a relatively normal Class A/B (Class H) amplifier with some new mods to the feedback topology. (The purpose of operating an amplifier in Class A/B in the first place is to minimize crossover notch distortion, and negative feedback is universally used to minimize all types of distortion; their innovation is a new way of applying feedback. In short, the difference between this and a "more normal" amplifier isn't like this one has fuel injection while everyone else is still using carburetors; it's more like this one has a "new and improved" version of fuel injection). And, from their specs, their new version seems to work quite well.

Please don't get me wrong..... I have a lot of respect for Benchmark, so I have no doubt that this will live up to its claims, and I'm also sure it will sound very nice; I just wouldn't expect it to sound dramatically different than any other well designed Class A/B amplifier of similar power.

I have to agree, though, that it is funny how much it looks like a classic DH-200 or DH-220 power amp.....
(Hey, it's a nice businesslike box with fins, and there's only so many ways to do that... )

[bootman]

Any real bench test results published anywhere?

[tchaik]

Feb 9, 2015 15:25:26 GMT -5 KeithL said:

It looks like a nice amplifier, but don't get too carried away about the "Achromatic" hype. From the technical details, it seems to be a relatively normal Class A/B (Class H) amplifier with some new mods to the feedback topology. (The purpose of operating an amplifier in Class A/B in the first place is to minimize crossover notch distortion, and negative feedback is universally used to minimize all types of distortion; their innovation is a new way of applying feedback. In short, the difference between this and a "more normal" amplifier isn't like this one has fuel injection while everyone else is still using carburetors; it's more like this one has a "new and improved" version of fuel injection). And, from their specs, their new version seems to work quite well.

Please don't get me wrong..... I have a lot of respect for Benchmark, so I have no doubt that this will live up to its claims, and I'm also sure it will sound very nice; I just wouldn't expect it to sound dramatically different than any other well designed Class A/B amplifier of similar power.

I have to agree, though, that it is funny how much it looks like a classic DH-200 or DH-220 power amp.....
(Hey, it's a nice businesslike box with fins, and there's only so many ways to do that... )

long live david hafler of hafler amps and dynaco. affordable for us audiophiles in a time of very expensive equipment.......

just musing.........

tchaik............

[KeithL]

Here's one review, with some numbers, which seems to substantiate their claims.

www.mixonline.com/news/outboard-gear/benchmark-media-systems-ahb2-power-amplifier/423155


I saw quite a few other reviews, including one from a subjectivist fellow who rather liked it, although he did feel that maybe using silver interconnects would make it sound more like his tube/hybrid "reference" amplifier....
Overall, I saw lots of positive and nothing negative.

Feb 9, 2015 16:07:09 GMT -5 bootman said:

Any real bench test results published anywhere?

[leonski]

380 watts bridged IMPLIES 190x2 @4ohms, nearly 2x the rated 100x2 @8ohms. Good performance.
Personally, I want to see measured power into a REACTIVE load which more accurately reflects a REAL speaker.
The power is infinitesimally less than my Parasounds and I suspect they'd be FINE driving my panels in biamp mode. No line level crossover YET.
And as far as measured performance goes, I'd be curious about headroom, as well. If 100x2 is IT, than I'd really want 2 or 3 db of dynamic headroom for 'peaks'.
But in my case, I run VERY LOW sensitivity panels and need that. Somebody with 90db or higher speakers? Not really necessary.

Some other measurables would be nice, including but not limited to 10khz square wave where the SMPS MAY be visible and a few other tests somewhat more
revealing than just hooking it up to a resistor.