Benchmark AHB2 in Mono Block Configuration


I've owned the Benchmark ABH2 Amp for a few years but am now considering one two alternative upgrade paths:

A New Amp or adding a second AHB2. If I purchase a new amp so far I like the Bryston 3BCubed which is a dual mono design with 200 watts into 8 ohms or possibly the 4BCubed at 300 watts. In either case this is more power than the single ABH2 at 100 watts into 8 ohms. However adding a second ABH2 increases the power per channel to 380 watts .

So much for raw power. What about overall sound quality? The Bryston 3BCubed got an excellent review on Absolute Sound as an amp that would require significantly more $$ to better. Another review I read easily preferred the Bryston 43Cubed (300 watts per channel) over the ABH2.

I'm in the process of completely upgrading my system after several years of the same components. I will shortly have:

An Aurender N20 Streamer into an MSB Discrete DAC with dual power supplies feeding the single ABH2 which drives my Harbeth C7es-XD speakers.

Everything will be new except the older ABH2. Hence the consideration of an amp upgrade.

Now Benchmark will tell you that adding a second ABH2 is only needed when the single amp clips. Other than that there is no sonic benefit to adding a second. I Ffnd that hard to believe. I would think having a second would offer improved soundstage, separation and possibly better performance from the speakers. So my question is:

Have any of you added a second ABH2 and if so what were the overall sonic benefits if any? Also any opinion or experience on the Brystons vs the Benchmark? Or any suggestions of a better upgrade path would be welcomed.


@yyzsantabarbara Thanks for info on the Mjolnir, it is tempting, but without a remote, it is a non-starter. I wonder how the Kara compares?

Note I came from a Freya+ -> Coda 07x - Benchmark LA4 progression, similar to yours. I just tried out an Ayre K-5XEMP, and it adds quite a bit of body to the sound. It is not quite a fit for me, but made me aware of another house sound.



@zlone I was looking for the remote for the Mjolnir (though I do not need one). No wonder I could not find it.

The Holo Serene may work for you. It is a bit warmer than the LA4 but has all the other sonic attributes of the LA4. 

The Mjolnir is a much better sounding unit than the Freya+. The Freya+ was a fun listen but would not have worked long term for me.


When one of my monoblocks (Monarchy  SM-70Pro) went out for repair, I used the single as stereo for a couple weeks and noticed quite a degraded change.  Upon return  of the second unit, it became apparent that having the monoblocks in place made everything tighten up; imagining, separation, detail... everything sounded organized and made me appreciate them together. 

Caveat, in monoblock configuration, I can also bi-wire and run balanced, to which could add to the elevated performance. 



There is an excellent review on Dogogo of the Benchmark AHB2 Monoblocks.  The reviewer really loved it.  If you get a chance, check it out it may remove all your doubt. 

@jfrmusic I made a decision today to buy a $10k set of headphones. Problem is I do not have $10k. However, I have a CODA #16 amp that can get me almost there money wise to buy the phones. I will be listening to phones more than the Livingroom system that has the CODA.

I have done extensive listening sessions with my Livingroom system and the CODA and AHB2. Infact, I wrote a thread about it here.

Audiogon Discussion Forum

This is what I feel needs to happen with the AHB2. It is not as strong on the bass as the CODA but on my new Yamaha NS5000 that is really not the case. On other speakers it was not as strong. I attribute that to the dips to 2 to 4 Ohm region.

The AHB2 can sound too hot on the mid and highs. I think that is an artifact of the upstream gear. I have a Benchmark DAC3B on my Livingroom system and it is too hot for the AHB2 (though not the CODA #16). A PlayBack Designs Dream DAC is a future buy and I think this solves the hotness issue. My much cheaper Musetec 005 DAC (sold) would likely also solve this issue on the Livingroom system.

When AHB2 amps are run in mono a speaker that does not dip too much into the 2 Ohm region should be used. My Yamaha NS5000 is likely one of those (I need to double check). One advantage of having monos in my setup would be that the AHB2 becomes even quieter. It also becomes louder by 4 or 6 dB at the same volume level as a single AHB2 (that is a big deal for me).

If you decided to sell your AHB2 and it is silver color give me a DM because I will likely go with monos after the headphone are sorted out. I already have silver a AHB2.

If anyone is curious this is the phone I will get.

(4) RAAL 1995 headphones, Magna and Immanis | Headphone Reviews and Discussion -

I am going to spend a few hours next week in Ventura, CA listening.