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Benchmark Media Systems AHB2 power amplifier Review

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In short – the Nordic Voices sound wonderful over the AHB2. There’s no trace of DSD noise or power supply switching artifacts. The amp easily extends into the highest notes of the sopranos without any distortion or limitation.

When it comes to SACDs the Oppo BDP-105 was the limiting factor, not the AHB2. The sonic signature was definitely Oppo’ish.

I used the Benchmark DAC2 HGC ($1,995) as a pre-amplifier and DAC. The DAC2 is an excellent DAC with a multi-input pre-amplifier for analog signals. It’s a marvel of compactness with 5 digital and 2 analog inputs, and 3 analog outputs. One analog output is XLR which matches with the AHB2’s balanced only input. There’s no XLR input on the DAC2 HGC so it’s not possible to stay balanced using the pre-amplifier. The DAC2 supports DSD and 24/192 files over USB.

The DAC2 is a good match with the AHB2 for computer files over the USB input. The improvements from the DAC1 are easily heard. DSD and 24/192 files become sonic treats. The Rebel Alliance is well positioned for the Computer Audio battle.

The pre-amplifier in the DAC2 HGC is good considering the size constraints of a small DAC. However, it is not in the same league as the amplifier. Both analog and digital tracks take a sonic hit going through the pre-amp section.

I did not realize the true potential of the AHB2 until I direct-connected my best sources, digital and analog. The AHB2 craves high quality sources and material!

Hooking up my Modwright Sony XA-5400 with XLR cables directly to the AHB2 yielded even better digital from SACD – albeit at ear-splitting levels. The Modwright is one of the best digital sources available without breaking (or robbing) the bank. The AHB2 did an excellent job on the tube amplified signal. Again, the music was a pass through of the Modwright sound – without any alteration.

 

Analog

My phono preamp is a B.M.C. MCCI. The MCCI is current amplified with a natural balanced design. By setting minimum gain on both the MCCI and the AHB2 I was able to enjoy some (normally) quiet music pieces. The AHB2 is outstanding on vinyl. Again I tried to identify any switching artifacts from the power supply but everything is analog-smooth.

Victoria de Los Angeles is one of the great sopranos of the 20th century. She has a wonderful voice and is perfect for evaluating the AHB2. I played an old Odeon/EMI LP with a recital collection of great arias, probably recorded in 1958, which I found sealed for five bucks. The AHB2 presented Victoria’s voice in its full glory with excellent highs. “Voi lo sapete, o mamma” from Cavalleria Rusticana sent chills down my spine. Mirella Freni as Mimi in the 1973 recording of La Boheme by Karajan and the Berlin Philharmonics is also terrific. The young Pavarotti as Rodolfo is reproduced with very good timber and extension.  Who knew The Force liked opera? And opera lovers will certainly like the AHB2.

Large symphonic pieces are truly special on the AHB2. The wide dynamic and frequency ranges can challenge lesser amplifiers. Benchmark’s claim that the regulation of the power supply provides clean, constant power under heavy load is evident when it comes to playing an orchestra at full output. Violins, drums, trumpets – they all sound great, especially at big crescendos or sweeping string passages a la Tchaikovsky.

The vinyl version of “Brothers in Arms” sounds even better than the SACD over the AHB2. This isn’t a result of the amplifier; rather, the AHB2 lets you hear exactly what you run through the input cable.

 

Sound Signature

So is there a sound signature to the AHB2?  Since THX calls it Achromatic we can assume that they were not aiming for a warm and sweet tubey sound – and this is not what it delivers. The sound is indeed neutral and exact without being sterile or clinical. Colorless? Not really. The amp will send through the sound palette of the source component and disc/file without stripping any color away.

I compared the AHB2 with my ASR Emitter I Exclusive Blue, which is a traditional Class AB amplifier design with an out-board transformer and battery for the pre-amp section. The Emitter is loaded with capacitors – some 1 million micro-Farad worth. Benchmark says they can achieve the same result with the Class A controlling amp and high frequency switching power supply. In direct comparison I’d say they are correct. Compared to my ASR Emitter the AHB2 is a bit cooler. Violins can have a more timber and color on the Emitter on good recordings. The AHB2 has better bass. Mahler’s 3d Symphony starts with a fanfare followed by hammering on the large bass drums. With the AHB2 the beats ring out like pistol shots – outstanding!

There’s a bit more quietness with the considerably more expensive Emitter. Both amplifiers are well suited to long audio session without listening fatigue (which is usually induced by sub- or super-sonic noise).

 

Female Voices

There’s been a comment in the press that the AHB2 gives a tonality/pitch change to female voices. On Sara K’s “I Can’t Stand the Rain” (SACD Hell or High Water, Stockfisch-Records) there’s no difference in the voice between the AHB2 and the Emitter. The AHB2 has more distinct bass and a sharper edge on the guitar line. The DVD-A version of Diana Krall’s Look of Love was identical on the two amps. Jennifer Warnes’ voice is one of the greatest. Her versions of the Leonard Cohen tunes on Famous Blue Raincoat on gold CD is a classic. “The Runaway Horse” is my favorite as it builds from a ballad to a funky Western song. The Emitter gives more nuance and color to Jennie’s voice while the Benchmark appears clear and clean with more distinct bass. Checking other vocals on SACD’s from Renee Fleming to Patricia Barber did not reveal any difference of consequence. I observed that it was easy to play the AHB2 louder – an effect of the low distortion – which sometimes makes the music sound a bit different.

 

Conclusions

The Benchmark AHB2 is a solid foundation for an audio system. It is very quiet with extremely low distortion. The Force has succeeded. However, dropping this amplifier into your audio system may not give you instant gratification. The AHB2 is so good it will immediately expose weaknesses in your system. It requires a very good pre-amp – which may cost as much or more than the AHB2 – which should output a balanced signal. Source components also need to be of top quality to get max return from the AHB2. And don’t expect your CD’s to sound much better – time to go high-res or analog. Benchmark may have Rancor (or tiger) by the tail with the AHB2 – it’s certainly tops their line sonically. On my wish list is that Benchmark comes out with a version of the AHB2 in which the 3 step input amp is replaced with a real volume control.

If your system meets the requirements above – the AHB2 will be an excellent reinforcement. The amp is sold direct from Benchmark with a 30 day return so it’s easy to give it a try.

Verdict: Cue John Williams’ “Star Wars Theme” (on high res January 2016).

The Rebel Alliance is victorious in the Amplifier Battle. The good side of The Force has prevailed.

Medals to everyone and a rebel princess to the AAA Technology inventor!

There’s a good word for Benchmark’s first effort in amplification: Bravo!

 

Copy editor: Laurence A. Borden

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