Benchmark AHB2 power amplifier

Clipdat
Clipdat Posts: 12,557
edited May 2019 in Electronics
I've been interested in the Benchmark AHB2 after hearing them in bridged mono mode powering a set of Martin Logans in the Benchmark room at Axpona this year - more on that forthcoming.

I just noticed that today ASR has posted up measurements from it:

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2-amp.7628/

Exceptional results, to say the least. Would very much like to get my ears on the AHB2 and review it.

Anyone have any experience with this amplifier?

Comments

  • heiney9
    heiney9 Posts: 25,053
    Measurements will never tell the whole story of an amps sound signature or performance. Also in general running a stereo amp bridged is a compromise in sound. If you want mono's, get mono's. Don't bridge a stereo amp into mono and think you're making something special, in most if not all cases, you're not.

    Let your ears and associated synergy with your other gear be the determining factor.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
  • mikeyb128
    mikeyb128 Posts: 2,885
    Haven’t heard one, but have been really interested in these as well. I’m absolutely obsessed with small, high power, high value amplifiers right now. Especially Hypex NC500 and Ice Power modules. I believe that class D has come along way, and in fact is right up there with a good Class AB.

    I’ve had 2 benchmark DACs. And they’ve both sounded phenomenal. If I were to go back in time, I would have kept my DAC2 HGC and not ventured off into the DAC rabbit hole.

    Just purchased a pair of M700 monos to try. Don’t have them yet, but curious what 700 watts will do to my power sucking Focals.

    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • Clipdat
    Clipdat Posts: 12,557
    mikeyb128 wrote: »
    Just purchased a pair of M700 monos to try. Don’t have them yet, but curious what 700 watts will do to my power sucking Focals.

    Oh! From a S300 owner, you are going to love them.

    @joecoulson loves his M700s.
  • steveinaz
    steveinaz Posts: 19,521
    I'm pretty sure Benchmark knows how to build a bridged amplifier correctly, since their specification measurements are generally regarded as "impeccable."
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Shop Spkrs: Elac Debut 2.0 B5.2
  • mhardy6647
    mhardy6647 Posts: 32,926
    edited May 2019
  • Clipdat
    Clipdat Posts: 12,557
    I actually forgot that I even made this post and found it just now via Google! haha.

    Anyway, my Benchmark LA4 preamp and AHB2 power amp review is finished and will be published soon!
  • steveinaz
    steveinaz Posts: 19,521
    Sweet!
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Shop Spkrs: Elac Debut 2.0 B5.2
  • Clipdat
    Clipdat Posts: 12,557
    Steve, I had to ship the gear back today and I can't stop thinking about it. Seriously depressing having to take it out of my system and box it up.
  • halo
    halo Posts: 5,616
    Looking forward to reading the review(s) Drew!
    Audio: Polk S15 * Polk S35 * Polk S10 * SVS SB-1000 Pro
    HT: Samsung QN90B * Marantz NR1510 * Panasonic DMP-BDT220 * Roku Ultra LT * APC H10
  • joecoulson
    joecoulson Posts: 4,943
    Still love the M700’s
  • Clipdat
    Clipdat Posts: 12,557
    I know you are new to forums Joe but try to stay on topic.
  • jdjohn
    jdjohn Posts: 2,987
    wpm0mqxmubod.jpg
    "This may not matter to you, but it does to me for various reasons, many of them illogical or irrational, but the vinyl hobby is not really logical or rational..." - member on Vinyl Engine
    "Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
    Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
  • Clipdat
    Clipdat Posts: 12,557
  • joecoulson
    joecoulson Posts: 4,943
    Clipdat wrote: »
    mikeyb128 wrote: »
    Just purchased a pair of M700 monos to try. Don’t have them yet, but curious what 700 watts will do to my power sucking Focals.

    Oh! From a S300 owner, you are going to love them.

    @joecoulson loves his M700s.

    Clipdat wrote: »
    I know you are new to forums Joe but try to stay on topic.

    hmm...
  • Clipdat
    Clipdat Posts: 12,557
  • steveinaz
    steveinaz Posts: 19,521
    LOL. Owned.
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Shop Spkrs: Elac Debut 2.0 B5.2
  • Clipdat
    Clipdat Posts: 12,557
    edited May 2021
    jdjohn wrote: »
    Sonically, my assessment is a very neutral and dynamic power amp, with no limitations that I could effectively test. It is clean from top-to-bottom of the frequency spectrum, with no coloration, and has impressive extensions in both lows and highs...simply no weaknesses. To reiterate, it only accepts balanced/XLR inputs, but has three settings of input level, so experimentation may be necessary, depending on preamp source.

    Bottom line is: at the $3,000 brand-new price, I am quite satisfied, and don't see myself selling my unit anytime soon.

    Great write up, Jody. Thanks so much for taking the time to share your listening impressions. I'll link to my original review thread here just in the unlikely chance someone hasn't seen it yet: https://forum.polkaudio.com/discussion/189753/benchmark-la4-preamp-and-ahb2-power-amplifier-review/p1

    I bolded some of your text above that I resonated with. Your assessments are spot-on and mirror what I heard when I initially listened to the AHB2. It simply reproduces the signal exactly as it receives it, with no modifications/adjustments. If you've ever had the un-mistakble desire that you want to "hear more", you can do it with this amp!

    Anyway congrats on your new amplifier and I'm not at all surprised that you love it! Happy listening.
  • VR3
    VR3 Posts: 27,965
    Very nice! I like the compact nature of the build as well!
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • SIHAB
    SIHAB Posts: 4,491
    Nice pickup @jdjohn. This could be my two channel set up except:
    They are building the PS Audio power plant for me as I type.
    I have the DAC2 HGC
    and
    I haven't moved on the pre yet but the Rogue is on the short list.
    Speakers: Polk Lsim, ATC SCM19 v2, NHT SuperzeroSpeaker Cables: DH Labs, Transparent, Wireworld, Canare, Monster: Beer budget, Bose ears
  • jdjohn
    jdjohn Posts: 2,987
    Thanks guys! One design aspect I'm not crazy about is on the rear panel, where they have the inputs placed below the speaker output binding posts.
    e9q33x2yh311.jpg
    With that configuration, and the preamp placed above the power amp (as is typical), the input cables and speaker cables have to cross. Of course if the preamp and power amp are side-by-side, it's not as big of an issue.

    One interesting thing that happened after swapping power amps actually had to do with my sub-woofer - an SVS SB-2000. The sub is driven (or fed a signal) by the DAC3/HGC preamp, so this is really about the preamp, not the power amp. The DAC3/HGC has two pair of RCA single-ended outputs, and one pair of balanced XLR outputs.
    puicez7arelb.jpg
    With my existing power amp, I was using one pair of the RCA outputs to feed the power amp, and the other pair to feed the sub. Once I had everything hooked-up with the AHB2 (via XLR) and the sub (via RCA), the output from the sub was suddenly MUCH louder. I thought I had accidentally turned up the volume knob on the back of the sub while switching it off or on, but nope. As I mentioned in my review comments, on my initial listening with the AHB2 in place, the volume output to my loudspeakers was very low. And again, the sub was suddenly very loud. But once I moved the internal jumper in the DAC3/HGC from the -20db setting to the -0- (disabled) setting, everything balanced out - both the loudspeakers and the sub.

    I'm not smart enough to understand it, but apparently moving that jumper from -20db to -0- (disabled) had the effect of increasing the output from the XLRs, and lowering the output from the single RCA. But again, with the setting at -20db, it drove both pair of RCA outputs sufficiently. In the DAC3/HGC user's manual, it refers to the jumpers as 'XLR Output Pads', and additionally as 'low-impedance passive pads'. Apparently, using the -10db or -20db settings increases the output impedance slightly. And even though the manual focuses on how these change the XLR outputs, it must also be affecting the RCA outputs as well.
    "This may not matter to you, but it does to me for various reasons, many of them illogical or irrational, but the vinyl hobby is not really logical or rational..." - member on Vinyl Engine
    "Sometimes I do what I want to do. The rest of the time, I do what I have to." - Cicero, in Gladiator
    Regarding collectibles: "It's not who gets it. It's who gets stuck with it." - Jimmy Fallon
  • verb
    verb Posts: 10,176
    Nice review Jody!
    Basement: Polk SDA SRS 1.2tl's, Cary SLP-05 Pre with ultimate upgrade,McIntosh MCD301 CD/SACD player, Northstar Designs Excelsio DAC, Cambridge 851N streamer, McIntosh MC300 Amp, Silnote Morpheus Ref2, Series2 Digital Cables, Silnote Morpheus Ref2 Series2 XLR's, Furman 15PFi Power Conditioner, Pangea Power Cables, MIT Shotgun S3 IC's, MIT Shotgun S1 Bi-Wire speaker cables
    Office: PC, EAR Acute CD Player, EAR 834L Pre, Northstar Designs Intenso DAC, Antique Sound Labs AV8 Monoblocks, Denon UDR-F10 Cassette, Acoustic Technologies Classic FR Speakers, SVS SB12 Plus sub, MIT AVt2 speaker cables, IFI Purifier2, AQ Cinnamon USB cable, Groneberg Quatro Reference IC's
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