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Benchmark AHB2 - To 'mono' or not to 'mono'

I own a single Benchmark AHB2 amp and have been considering another in order to run both in bridged mono mode, which will provide significantly more power to my speakers and presumably, greater dynamics. I've read in other threads where other owners (and perhaps others with opinions) had implied both positive and negative impressions concerning this approach. Assuming I'm not considering purchasing other amps at this time, does anyone have experience with both approaches and will you please share your impressions?
wwoodrum
ssnkssnk
21 posts
 
Recently I added a second AHB2 to my system to run it in mono.

I was running MacBook Pro (JRIVER) > Benchmark DAC3 > AHB2 > ATC SCM19v2 (as of yesterday – there are two ahb2, running in mono and providing 380watts into 8ohms). My speakers are ATC SCM19v2 (85db / suggested power from manufacturer is 75-300 watts), so I was hoping to get better performance with more wattage.

 After reading posts from different fellow members on this site and other forums, I was not expecting any big changes in the sound quality. But boy, I was so wrong. I guess different ear hear differently.

 I was very happy with single AHB2 (100watts) pumping music into my speakers, with great sound-staging, tonal balance, accuracy, clarity, bass punch, excellent mid-range etc etc. But sometimes, with some tracks, I did wish for fuller/warmer sound, and was doing google research into some tube preamps to use with my setup for the occasions when I really wanted that extra warmth. That problem is now solved with two units.

With two AHB2 (in mono configuration), the sound quality has changed considerably. Tracks which sounded thin earlier, were fuller with more ‘body’ and warmth. The sound staging is definitely much better now. It has completely changed my listening experience to say the least.

 I am expecting to spend more time with my system over the coming weekend, and will share more soon.

Hopefully, I will like this change.

georgehifi's avatar
georgehifi
10,312 posts
 
With two AHB2 (in mono configuration), the sound quality has changed considerably. Tracks which sounded thin earlier, were fuller with more ‘body’ and warmth.
That to be expected with half the damping factor and double the output impedance, that will always make the bass and lower mids sound richer.

Now try vertical passive Bi-Amping with the both amps back in stereo mode, and prepare to be amazed!!!
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George
mijostyn's avatar
mijostyn
8,178 posts
 
georgehifi in order to make that work right you need a rather expensive digtal crossover to do it right. Then you bypass the in speaker analog network.
ssnk you really should look into Channel D's Pure Music. You do have to buy it but you get a free trial period. It will use your iTunes as a library and does neat things like network stream and up sample. It was designed to work specifically with Apple computers.
georgehifi's avatar
georgehifi
10,312 posts
 
georgehifi in order to make that work right you need a rather expensive digtal crossover to do it right.
No sorry your wrong, forget digital xovers your still using the speakers internal xovers.
Just vertical bi-amp as per the link, if you have 4 speaker terminals on each speaker (remove the links between them).
The sound will be far better than bridging the amps into mono.
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George
wwoodrum OP
54 posts
 
George,

How do I split the output from the pre-amp/DAC? Does someone make a decent splitter cable with XLR terminations? Or am I missing something?
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