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.


Your budget is out of my league but I have been most impressed with Ayre Acoustics amps. I have compared them to Bryston and they consistently sound more grainless, transparent, and musical. This is the $12K stereo amp I am referencing. At 52lbs, it’s not a hernia machine either. VX 5-Twenty. 


Interesting experience with the ABH2. Although I don’t understand how the mono ABH2 would fair worse than a single driving lower ohm speakers since the power is significantly higher with the mono configuration 


I agree and also I will most likely sell my HPA4 as the volume control on the MSB will be sufficient. 

As to tube amps. Been there not going back. 
To all: Thanks for your thoughtful responses. I appreciate it. 


Checkout @arafiq system. He has extensive experience with Harbeth’s. He is using Vitus SS amp. Maybe he can chime in to share his experience with Vitus.

And S510’s are on another level than T/5X subs :-)

@jfrmusic The watts are higher in mono but those watts cannot be used continuously (say 30 minutes) at 2 Ohm, which some speakers dip too. The single AHB2 can continuously drive a 2 Ohm speaker but at 190 watts (I think).

I see some posts above on the CODA. Let me chime in on this too.

I used a Benchmark LA4 on the CODA #8 and the CODA #16. They both are good with the #16 approaching great. The #8 lacks some clarity that I like with the #16 and AHB2.

Another amp that I like more than the #8 is the Sanders Magtech. I recently heard from someone with informed knowledge on this that CODA was involved in the design of that amp. The power supply is from Sanders. This amp, which I bought from Sanders used for $4k, is even better than the #8. I think it is the top end that is better than the #8. I love the Magtech on my Magnepan LRS+. The #16 is also great on the LRS+, but I use it elsewhere.

@zlone I am currently listening to the Schitt Mjolnir preamp (from 2023) with the Sanders and the LRS+. Great sound, a bit too warm for me for long term listening, I like the Holo Serene and Benchmark LA4 for long term preamp duties. The Mjolnir is a pure Class A preamp and a very nice unit. It is a 2-channel preamp and headphone amp, though the headphone amp does not work well with my funky RAAL CA-1a phone. Do not let the price fool you.

Schiit Audio: Audio Products Designed and Built in Texas and California

Edit: I am doing some testing on my office with the Holo Serene preamp and the Schitt Mjolnir. I cued up the Isley Brothers 3+3 on both preamps and for my ears the utter neutrally and clarity of the Serene wins over the warm Class A of the Mjolnir. The only thing the Serene lacks is a balance control. If I can make my off centre seating work without the balance control I am keeping the Serene with the Sanders. A great combo.