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Old 05-16-2015, 11:30 AM
aqman aqman is offline
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Default Benchmark AHB2 Amp

I've had this amp for a few months now and thought it would be nice to post a few impressions. I've been using it with Benchmark's own DAC2 pre-amp and that combo with both Vivid B1s and PSB Synchrony Ones. There is much easily found on how it works, ect, so I'll just give my take on it. The two other amps I've used extensively with both speakers are the Bryston 4BSST2 and Ayre V5xe.

In short, it's awesome. Very smooth mid and highs and tight control over the bass. If this is what a class A amp sounds like, I can see what I've been missing. It goes louder than I need it to. No problem playing Daft Punk at house party type levels in a big room on the PSBs.

This amp does not give any mid bass warmth. The extra bass extension compared to the Ayre is very striking. I think even better than the Bryston. Soundstage, vocals, everything really, seems just right. I have no desire to move on to anything else.

The small size is really convenient. I was rearranging cables, and instead of getting behind some 100 pound stack of electronics, I just picked up the amp,dac/pre and music server and set it on a table.

It shuts itself off after 45 minutes of no signal. Not a big deal, but pre amp stays on, so have to turn amp on by hand or cycle pre off/on to trigger amp. I think I hear a small change in sound for the first 5 minutes, but I could be imagining that.
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Old 05-16-2015, 01:10 PM
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I've been waiting to hear some positive reviews of this amp. Keep us posted!
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Old 05-26-2015, 06:12 AM
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Thanks for the review. When this amp was announced, I was interested by the incredible signal to noise ratio they were quoting. I am not aware of any other amp that gets close.

But it is not a Class A amp; it is about as far away from Class A as a Class AB amp can get.

I don't understand why Benchmark have an auto shut-off, but no auto power up on signal, which is what everyone else does. That would annoy me. Given it looks like it would consume very little power at idle with a SMPS and class-H supply rails, it is all a bit odd.

Given how low the distortion is on this amp, I am sure you are correct that it would take 5 minutes or so for the transistors to reach their correct operating temperatures and stabilise the circuit.
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Old 05-26-2015, 02:47 PM
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Quote:
Originally Posted by aqman View Post
I've had this amp for a few months now and thought it would be nice to post a few impressions. I've been using it with Benchmark's own DAC2 pre-amp and that combo with both Vivid B1s and PSB Synchrony Ones. There is much easily found on how it works, ect, so I'll just give my take on it. The two other amps I've used extensively with both speakers are the Bryston 4BSST2 and Ayre V5xe. In short, it's awesome. Very smooth mid and highs and tight control over the bass. If this is what a class A amp sounds like, I can see what I've been missing. It goes louder than I need it to. No problem playing Daft Punk at house party type levels in a big room on the PSBs. This amp does not give any mid bass warmth. The extra bass extension compared to the Ayre is very striking. I think even better than the Bryston. Soundstage, vocals, everything really, seems just right. I have no desire to move on to anything else. The small size is really convenient. I was rearranging cables, and instead of getting behind some 100 pound stack of electronics, I just picked up the amp,dac/pre and music server and set it on a table. It shuts itself off after 45 minutes of no signal. Not a big deal, but pre amp stays on, so have to turn amp on by hand or cycle pre off/on to trigger amp. I think I hear a small change in sound for the first 5 minutes, but I could be imagining that.
I was also interested in this amp back when it was announced by got tired of waiting. I guess I will take another look at it. Thanks for sharing.
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Old 05-27-2015, 10:43 PM
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A few more random things.

I can put my ear up to the tweeter when amp is on and hear exactly nothing. Although I think it's the lack of higher order and IM distortion that makes it sound so clean.

Indications are that there will be reviews on Soundstage network and Stereophile coming up.

You can try it and return it before 30 days for a refund through Benchmark's risk free trial program.

Similar to Devialet, it uses a ultra-linear class A amplifier as a reference for the power section. Things get radically different from there.

I'm still very happy with it. Would be great to get other opinions.
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Old 05-28-2015, 01:46 AM
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I'm wondering if this is the amp that Bascom King referred to in an interview I watched.

He didn't name it except it was by a company that was known for making DACs - and that the amp measured incredibly well but sounded very uninvolving.
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Old 05-31-2015, 09:59 PM
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The SoundStage Network review is up:

http://www.goodsound.com/index.php/e...mono-amplifier

Conclusion:

"Benchmark Media Systems’ modest-looking little AHB2 power amp may be hi-fi’s biggest bargain. It is one of the -- if not the -- quietest, most resolving amps I’ve heard. Time and again, without ever having intended to, I wound up hours deep in listening to the fringes of my music collection, thanks to the AHB2’s reference-level transparency and obscene athleticism. If ever there were a giant-killer of an amp, this is it."
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Old 05-31-2015, 11:37 PM
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Quote:
Originally Posted by doggiehowser View Post
I'm wondering if this is the amp that Bascom King referred to in an interview I watched.

He didn't name it except it was by a company that was known for making DACs - and that the amp measured incredibly well but sounded very uninvolving.
Unlike his.
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Old 07-08-2015, 04:35 PM
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I own the Benchmark AHB2 and to my ears it is a phenomenal amplifier. Dead silent and as musical as a live acoustic performance. The combination of grain free class A type sound and the dynamics of the best solid state can deliver is in my experience a rare feat. I have always been partial to tubes and this amplifier has replaced some fine tube equipment. I could not be more impressed. The review linked above matches my experience.
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Old 07-13-2015, 10:36 PM
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Interesting interview with John Siau from Benchmark Media regarding this incredible amplifier.

The Poor Audiophile: The Technology Behind the AHB2 Power Amplifier: An Interview with Benchmark Media's John Siau
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