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Benchmark AHB2 in Mono Block Configuration

Hi:

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.

jfrmusic
jimmy2615
436 posts
 

So you went with the N20 ?  Nice!  That’s quite a digital front end combination with the MSB.  I had Harbeth M40.2 paired with the AHB2 monoblocks.  It was by far the best amplification synergy I had with those speakers.  I preferred them to a stereo Luxman M900u.  Since you already have one, you know how it sounds and whether you like the sound.  Adding another one may or may not change the sound.  The M40s can use that extra power.  Adding a second one did improve the sound IME.  Bass became tighter and everything more focused.  I’m not sure about the SHLs.  I think you’d just have to try it to see for yourself.  

koestner
667 posts
 

Some people have done the bridging and liked it a lot while others have not. This tells me that it's system dependent. With the number of AHB2 amps that come up, and go on the used market, it would be very easy to try it yourself. That's the only way to know for sure. I know... everyone says that, but this time it's so very true.

lalitk's avatar
lalitk
5,440 posts
 

@jfrmusic 

I glanced at Harbeth C7es-XD specs, doesn’t look like they need whole lot of watts to drive them. I think you will get much better result with adding dual subs (like REL S510’s) over mono blocks. 

jimmy2615
436 posts
 

Edit…sorry, I meant your Harbeth C7s, not SHL5s.

jfrmusic OP
266 posts
 

@lalitk 

I had dual REL T/5X subs but could not get them to integrate to my satisfaction with the Harbeths. The T Series RELs are really low end re enforcement rather than deep below 30 hz subs unless you move up to their bigger units. I liked the low end of the Harbeths which are -3db at 45 hz and my frequency analyzer shows output below 35hz. The RELs we’re just doubling up the natural low end of the Harbeths and it had a negative effect on soundstage and openness. 

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