2. amps-preamps
  3. 184615-182267

Benchmark AHB2 or Class D (GaN FET)

The Benchmark AHB2 seems to be a different twist on linear Class AB amplifier design.  This amp uses a different approach to distortion cancellation that gets around some of the problems of using large amounts of negative feedback.  It uses a THX patented technology (under license) called AAA.  This amp has been around for several years. It gets rave reviews, so I am surprised that the technology is not in more widespread use.

I am interested in why this approach is not more widely used.

Also, how would this amplifier compare to the newest Class D technology, which uses GaN FETs and much higher switching frequencies.  (GaN Class D amplifiers which are price-competitive with the AHB2 are the LSA Voyager and Peachtree).  

At a higher price point would be Atma-Sphere Class D monoblocks and the AGD Tempo.

I would appreciate hearing the forum members' opinions on the AHB2 technology vs the latest Class D amps.

 

Thanks,

hifinut51
timothy_m
35 posts
 

Well, the Hi Fi Critic sorta killed this thread.

recklesskelly
330 posts
 

Benchmarks amplifiers are not Class D. 

yyzsantabarbara
4,490 posts
 

I have owned the AHB2 about 5 times during the past 10 years. I think I may have made money on the amps, though that was not the intention.

I have the Peachtree GAN1 that I mentioned in my prior post. I also have the Peachtree GAN400. I was totally satisfied with the GAN400 on my slightly bright Magnepan LRS+.

However, I had negative listening session with my Yamaha NS5000 and the CODA #16 in my other system. That session made me miss my cleaner sounding Benchmark AHB2’s which I think would be a nice match for the slightly warm NS5000.

I then paired the slightly warm CODA #16 with the slightly bright LRS+ and that combo was better than the GAN400 with the LRS+. We are talking Class A vs Class D and GAN. The cost is $16K vs $2K.

When I compared the GAN400 with the #16 on the LRS+. I notice that the GAN400 had a bit of hardness on the top compared to the smoother #16. The #16 sounds more full or organic while the GAN400 is a bit drier. Saying all of this, I loved the GAN400 on the LRS+. It is just the #16 is a perfect amp for the LRS+.

The CODA #16 stays with the LRS+. I will likely get a pair of AHB2 monos to try out with the NS5000.

I am returning the GAN400 tomorrow because it is not as good as the AHB2 I am going to try next. The AHB2 and the modded Peachtree GAN1 are more comparable. Though the 200 watts on the GAN1 are not enough for my NS5000 and the GAN1 is a PIA to use.

The HiFI Critic likely likes gear that I think is sheete, so who is correct? No one really.

BTW - I also owned a LSA Voyager GAN 300. I also had that one modded. The PeazchTree GAN amps seem a bit better to me, definitely the modded GAN1. I like the GAN400 more than the LSA Voyager. It seems to bit more powerful. I like the AHB2 over all of them except the modded GAN1 which is in the same class as the AHB2, but warmer.

 

 

peter_s
1,313 posts
 

I’ve had the AHB2, the Atmasphere and the AGD Audions, and I greatly preferred the Audions.  I found the AHB2 to be non engaging and the Atmasphere to be a little harsh in the upper frequencies.  In contrast, the AGD was neutral, fast, black background, delicate with great imaging.  Definitely keepers!  I hope that other ganfets catch up!

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