Review: Benchmark AHB2 Amp

Viking64

TL;DR

Emlyn

I'm not saying Denon and Marantz receivers won't run a full home theater system, but am saying most receivers alone won't get the best out of the Reserve speakers above a certain point. Pioneer Elite receivers with Class D amps were an exception but the two I still have don't really sound all that great to me by themselves for anything but movies.

Anyway, the main topic here is high quality amplification for stereo listening enjoyment rather than watching a movie in surround sound. I do agree that B&K amplification was way ahead of most because they cared about their customers in that regard. They went out of business not because of their amplifiers but because of not being able to bring their own processors to market and compete. Parasound learned that lesson before it was too late for them. I ran through a few B&K pieces and really enjoyed them but once the company was gone so was my B&K gear.

FWIW, I've been tinkering with home theaters for a bit since I was a youngster back in the days of Dolby Matrix surround in the 1980s. I had an excellent high-current Akai integrated amp back then that broke after a couple years and no longer had repair parts available and the company offered me a brand spanking new comparably priced "home theater" receiver as a replacement. The integrated amp had no problem powering my main speakers and sounded a whole lot better than the receiver and the receiver had a habit of blowing out the tweeters on my speakers. Fortunately just needed a trip to Radio Shack for replacements back then. But, lesson learned long long ago.

treitz3

....and we are off.

Gentlemen, place your bets now.

Tom

VR3

Marantz cinema 30, 140 watts 8 ohm



Mark levinson 33h 150 watts at 8 ohm


We are the same!

daddyjt

mantis wrote: »

Emlyn wrote: »

Polk has been recommending separate amplification since introducing the ring radiator tweeter on its LSi lineup more than a couple decades ago. It's mainly the tweeter that presents a difficult load. When that line was introduced there were a handful of home theater receivers rated as being 4 ohm stable. Now, most mid-grade and up receivers are capable of running Polk's speakers that have that type of tweeter. The whole Reserve line is rated as being compatible with amplifiers that are 8/6/or 4 ohm stable. But merely being compatible doesn't mean a relatively small power supply in a receiver shared across 7 or more speakers wouldn't benefit from some supporting power. The tweeters in the LSiM707s get hot even with high current amplification when driven hard.

A receiver won't get the best performance out of the speakers and in the hands of people who don't know any better and drive a system at too high a volume for too long warranty repairs eventually become necessary because of blown tweeters. This is also why all but the cheapest receivers have pre-amplifier outputs. If knowledgeable customers wouldn't benefit from having them they wouldn't be there, right?

I usually recommend that someone who's interested in home theater as a hobby at least get a separate amplifier like an Outlaw Audio Model 5000x or 7000x. I have both and both are way better than any receiver at powering 4 ohm load speakers in a multichannel home theater system. But they are not intended to be the highest quality two channel amps. I switch over to Parasound or something else for that. Marantz does also make separate and integrated amps!

Crutchfield recommends high current separate or integrated amps for all of the Reserve speakers, not just the big R700s which dip down to 3.6 ohms minimum. This is from their R200 listing.

"Recommended amplifier power: 30-200 watts
high-current amplification from a quality power amp or integrated amp is recommended for best performance"

I'm glad you have some experience . You base your decesions to discount the ability of a AVR to power a theater system by spec, not by experience. My question to you is out of the 7 Theaters you spec'd and built or helped your friends do, how many had AVR's that just couldn't get the job done?
Yes I'm in the Industry , Yes I have built spec'd and installed Hundreds of Surround systems and Theater ranging from nice small family Room Bose systems to Million Dollar Wilson / Krell / Proceed etc stuff over my decades in this business. I'm not looking to measure that.

I completely disagree with you that you can't power a Theater system with a AVR because you're using internal amps. That is simply not true UNLESS you spec a AVR that does NOT have the ability to power a speaker package in a larger room that the AVR simply can't do. That my friend , we can agree. I have seen clients from companies that I have worked for in the past decide to purchase against the salesman recommended AVR and go with a less powerful unit and yes it was underwhelming and struggled to power their speaker package in their room at reference volumes.
Now under reference volumes , most AVR's will get the job done and satisfy most people. I've seen it hundreds of times. However I have also used AVR's in countless theater rooms and family lifestyle rooms where you couldn't run the AVR out of gas no matter how loud you play it.

So you again are looking at spec's and saying shared power and all that stuff matter , I can tell you, hardly never ever have I seen this happen in the real world. Powering a full Dynaudio Theater system or B&W or Monitor Audio or Klipsch or name a brand that has a line of theater speaker setups and I can match them with the room dimensions with a AVR that will power them.

So to support your point on spec's and amp shared power in a AVR, there are demands that an AVR simply can't support and you absolutely need to add external power amps or go separates , not so much today but in the past, preamps where more popular as the noise floor in older AVR's where not on the same level of dedicated preamps, that was true then not today. But again a Theater of the size 25 x 45 with all Martin Logan speakers no AVR I know of can power such a system in a 9. 2 configuration. So in this very case we can agree. I used all Proceed amps to power all these Martin Logan speakers.

Another example where you are right was a Wilson Audio Theater system I did. We used all Krell Monoblocks as a AVR was simply not going to power this system in a 20 x 31 room.

Blanket statements like yours and throwing spec's around hold NO water unless you put it into a room and speaker package. If you build a Klipsch Theater system, hardly never do you need external power amps. Marantz , Denon or Integra AVR's when again spec's correctly for the space and speaker package will absolutely drive that system into Reference with plenty of head room for dynamic passages.

The older LSI speakers from polk, yes they were power hungry and needed more current than the RT line which required much less to achieve a good theater experience. No power amps where not always necessary, I had a B&K AVR that powered the LSi's to breaking point with the internal 125 watt amp which by the way was the same exact power amp as the stand alone 125.7 you can buy. How do I know that? I watched them build it at the B&K factory in NY when I went there for training. I watched them hand build amps preamps and AVR's and all the parts they used where exactly the same in different chassis. The LSI system also responded very well to when I purchased a Pioneer Elite ICE AVR which was fantastic back in the day SC-07. It had plenty of power to drive my entire LSI 15 , LSI C , LSI 7's and LSI FX speakers to Reference levels with no issues overheated or Shut downs.

When power is needed , it's used , when power isn't needed , it's not used. You would be surprised on how many people use 1/8 of the power they have on a day to day basis to drive their speakers to levels satisfying to them. It's not always about Reference levels as not many people inlcuding everyone in this forum do not listen at Reference levels, If they did , their hearing would be damaged and then the joy of listening would be compromised.

So having this interesting conversation with you I'm not interested in Gotcha or your dumb or anything like that. But you made claims as other did on this thread about AVR's not being good enough to do the jobs they where built for. That is simply not true. Maybe many on here feel that way and that is perfectly fine. Add all the amps you want.

Phil the thread starter has very nice speakers , he changes them a lot but guess what? Ask Phil how loud he listens to he's system, I had to ask him many times to turn it up as he does NOT like it overly loud or anywhere near reference levels, it becomes uncomfortable for him and I do NOT judge him for that. He likes what he likes, he has WAY more power then he will ever use, He has REL subwoofers all over the place and they never crack a sweat. I have been to Phil's house a few times and got the pleasure of actually enjoying his company , his system and NEED all that power he has? No, his Yamaha AVR has more power than he will ever need or use but he enjoys this hobby like the rest of us as he sees fit and if he wants Parasound or whatever amp he desires and puts in his system because he likes it, I'm completely fine with that. But I'm also not going to tell him he needs it when he does not.

Apparently you and I desire different levels of performance in a home theater, and that’s fine. You are correct in your assertion that an AVR is “good enough” for the majority of HT customers. That said, I will stand by my statement that I have never encountered a situation where external amplification did not make a substantial difference in sound quality. This is also to say nothing of the myriad drawbacks of the “everything in one box” compromise of an AVR.

We now return you to your regularly scheduled programming. Apologies @pearsall001 for the thread hijack…:-)

daddyjt

VR3 wrote: »

Marantz cinema 30, 140 watts 8 ohm



Mark levinson 33h 150 watts at 8 ohm


We are the same!

Just looking at those innards gives me a shot of PTSD from my repair of the 331. Both a marvel of engineering and a nightmare to work on at the same time. These amps will certainly challenge the perceptions of “rated power”…

VR3

They should have just stated the spec as per limited by incoming power from wall.

pearsall001

Well let's see if we can get this thread back on track. These things seem to go sideways at times. LOL!

First off this is not at all about power. In fact I'm giving up a ton of power. The A21+ is rated at 300/500 into 8/4 ohms whereas the AHB2 is rated at 100/190 into 8/4 ohms. One would certainly think this wouldn't be a fair fight. Things can certainly be deceiving though.

To address the HT issue I'm sure my Yammie AVENTAGE RX-3010 AVR can handle my HT needs but I've always had a dedicated 2 channel amp for double duty running my fronts in both HT & for 2 channel.

I purchased the A21+ a few years back to give my Maggie 1.7i's some more juice. I certainly did the trick & kept me quite happy. Now the Maggies have been replaced with JBL HDI 1600 monitors (85db/4ohm). The reason on switching things up is downsizing & wanting to replace the A21+ with a smaller, lighter amp without sacrificing musicality. I did extensive research & took a shot with the AHB2. I never heard one in person & went strictly by reviews & Benchmark's no risk 30 day return policy.

A little about my room (13x30x7) & also I've been in this house since 1992 & the room hasn't changed except for new furniture over the years & always in the same spot so it's safe to say that I know my rooms sonic attributes like the back of my hand. So whenever I would audition new gear it didn't take me long to decipher whether it was a keeper or just a lateral move.

Now enter the AHB2...I had no idea what to expect and was unbiased in my upcoming listening challenge. To be brutally honest I was taken back by the AHB2 & it literally walked all over the A21+! Yes you heard that right, the AHB2 was like David vs Goliath. I was in disbelief at first but needed to validate my listening experience. As good as the A21+ is, & it's one fine amp the AHB2 just revealed things that the A21+ just wasn't capable of.

A few of the AHB2's attributes: It delivered so much more detail in low level listening that I didn't know was there until I actually heard it & this is with music that I've very familiar with. Again scratching my head here with what I'm hearing. The music just sprang to life in ways that were not present with the A21+. There is no sweet spot with this puppy...the sweet spot is now the entire front stage, behind & off to the sides of the speakers, I couldn't believe it. I just find myself enjoying the music so much more now & am totally engaged in ways that I didn't experience with the A21+. Needless to say it's found a new home & I couldn't be happier. If anyone is looking into a new amp I can highly recommend you put this on your list.

Also you can always add another one if you feel the need for more power & run them both as mono blocks. Benchmark designed these to perform just as well in bridged mono as stereo.

Cheers,
Phil

skrol

Do I dare dip my toe in the HT vs 2ch debate? I will this time because of something I noticed yesterday.

Yesterday I was listening to music through my Marantz SR-7010 driving my upgraded RTA-11TLs, which I consider fairly easy to drive. The source was my a modern remis of Abey Road, Pioneer PL-530, a Grado Gold cart that I got from F1Nut, and a Parasound phono pre. The sound was good but I felt it was lacking something. The separation was very good, as was the perceived frequency response. I tried with the Audasy tuned, Direct and Pure Direct. Not an A/B test but comparing to my Parasound PLD-1100, same phono pre, and HCA-1000A or even my 2ch Denon DRA-835 or Harman Kardon PM665; while technically accurate and having plenty of power to drive the RTAs, the music seemed to lack life. Perhaps it is in the imaging or transient response?

There are so many variables that can influence the sound without doing a controlled A/B test. I do wonder how it would sound using the SR-7010 as a pre-amp feeding the HCA-1000A.

Emlyn

In my case I had to step up to the former top level Marantz AV-8805A home theater processor to finally get satisfactory two channel sound in my home theater system. It's pretty close to my dedicated two channel system, but still only close. The SR-7011 I was using before the 8805A wasn't close to it in performance for two channel music even with separate amplification. Was good for home theater though. Relatively lifeless for music in comparison sums it up for me too. Too much digital noise stuff going on inside that receiver's box even with the engineering they put into it and the pure direct mode. I still needed to have a separate two channel system with gear designed just for that usage.

This is why I was mentioning earlier than Phil might benefit further from doing a demo of the Benchmark LA4 preamp with the AHB2 amp. It may turn out to be diminishing returns compared to the receiver used as the preamp...or it may not. May be worth a call to the good folks at Benchmark.

pearsall001

As it stands now I'm quite happy with my Parasound JC2 BP pre. Maybe down the road the LA4 might be an option for a test run.

Emlyn

That's a keeper. I haven't found a good reason to permanently replace my JC2 with something else since I got it in 2012.

pearsall001

Emlyn wrote: »

That's a keeper. I haven't found a good reason to permanently replace my JC2 with something else since I got it in 2012.

Same here, I think my front end is here to stay for awhile. My only other itch that might need to be scratched is to add another REL S812 into the mix.