Benchmark AHB2 Impressions (vs. Vidar)

Discussion in 'Power Amps' started by purr1n, Sep 24, 2017.

  1. rlow

    rlow A happy woofer

    Pyrate Contributor
    Joined:
    Jul 18, 2017
    Likes Received:
    7,738
    Trophy Points:
    113
    Location:
    Canada
    Ok if you feel "a bit of a bullet" is an attack against those that like this amp, I retract it. I was referring to @Marvey and others characterization of this amp vs. Vidar - it does not sound like I would have personally preferred it at all, and potentially been pretty dissapointed considering this would be the single biggest purchase I've made in my 2-channel system so far - yes it would have been a fairly sigificant financial outlay for me, although hopefully temporary if i flipped it, as you've said. Those amps on CAM did have some damage as well which made me nervous about resale (likely unjustified, who knows)
     
  2. strangecargo

    strangecargo Acquaintance

    Joined:
    Apr 9, 2017
    Likes Received:
    48
    Trophy Points:
    18
    Location:
    San Francisco
    I've had an AHB2 for about 6 months, driving a pair of Dynaudio Contour 30s. I think it's an excellent combination, with great soundstage, tonality, timbre, and macro/micro dynamics. It also sounded similarly great driving a pair of these DIY speakers that I recently built for a friend. However, I've also heard the AHB2 sound pretty lackluster, driving my other speakers (Sonus Faber Amati Futuras), as well as @Jozurr 's HE-6s. In those cases, my criticisms would line up pretty well with how @Marvey describes his experience. I don't think there are any bullets to be dodged here. Just a matter of determining whether or not it works well driving your gear.

    I think it helps to have a good preamp; I wasn't aware of just what the Esotar2 tweeters in the C30s or the AHB2 were capable of in terms of high-frequency harmonics, reverb, or portrayal of room acoustics until I swapped out the preamp in the DAC3 with my build of @tomchr 's differential preamp design.
     
    Last edited: Sep 28, 2017
  3. rlow

    rlow A happy woofer

    Pyrate Contributor
    Joined:
    Jul 18, 2017
    Likes Received:
    7,738
    Trophy Points:
    113
    Location:
    Canada
    Seems to be a common thread with regards to reviews of this amp, that it may be a bit more sensitive to partnering equipment than some others.
     
  4. strangecargo

    strangecargo Acquaintance

    Joined:
    Apr 9, 2017
    Likes Received:
    48
    Trophy Points:
    18
    Location:
    San Francisco
    My educated guess would be that you'll get great results with 8Ω speakers or 4Ω speakers with fairly benign phase/impedance curves. I don't have any experience driving the AHB2 with SE inputs or anything but the lowest gain setting, so I can't say if either makes much of a difference.
     
  5. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    My view is the opposite. Probably get best results with 83db inefficient speakers with complex 76 piece crossovers and uneven impedance and phase response. AHB2 seems like the kind of amp that's good at powering through all this crap to get a grip on the drivers. Folks who prefer warmer presentation or like the edge taken off should stay away. Source is going to be paramount, the kinds that are good at reproducing depth, layering, and ambient cues that give us a sense of the venue (and assuming capable speakers that can translate this) will suffer more.*

    Again, superb with not committing sins of commission. Not quite so with sins of omission. My priorities tend to be opposite this.

    * For example, I'm finding that the active filter RSA phonostage which has a more upfront stage to be less affected. However, this phonostage's transient snap and more neutral presentation compared to the one I am running might require me to push the speakers back a bit.

    I guess my deal is that I was left to believe the AHB2 was "true high end", or that it was close to it, along the lines of the low power vintage Pioneer M22 or high power Hegel H2. It's not. I can imagine this as very solid under the right synergies, but that magic, that engagement factor, just isn't there. (Trying out B&W speakers right now.)
     
    Last edited: Sep 28, 2017
  6. Daveheart

    Daveheart Friend

    Pyrate
    Joined:
    Jan 10, 2017
    Likes Received:
    566
    Trophy Points:
    93
    Location:
    Dallas, TX
    Which model?
     
  7. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
  8. Serious

    Serious Inquisitive Frequency Response Plot

    Pyrate BWC MZR
    Joined:
    Sep 28, 2015
    Likes Received:
    2,594
    Trophy Points:
    113
    Location:
    near Munich, Germany
    You mean there's a way to make them not sound like ass?
     
  9. ultrabike

    ultrabike Measurbator - Admin

    Staff Member Pyrate MZR
    Joined:
    Sep 25, 2015
    Likes Received:
    8,960
    Trophy Points:
    113
    Location:
    Irvine CA
    I might have heard those B&W (or similar) at Best Buy a few times. To me they are too warm and screwing in general. I think they look really nice. To bad they don't sound nice.

    Based on what I've heard I believe they are beyond redemption, and likely will sound like ass no mater what is driving them.
     
  10. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    They just need a ton of good quality power. (Have tried these with a variety of amps in the past). Otherwise warm, mushy, and sleepy. I doubt anything at Best Buy would be up to the task. Either way, I do have two other SS amps to compare against.
     
  11. Negura

    Negura Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    180
    Trophy Points:
    43
    Location:
    London, UK
    The AHB2 is also superb with high efficiency speakers. It's extremely quiet, even with two of them bridged. I usually run it (or better said them since I have a pair) with a pair of 96dB, 5-8ohms actual impedance range, Tannoy speakers. It drove even the relatively efficient Focal Utopia exceptionally, with no hint of background whatsoever. In fact I preferred the Utopia off the Benchmark compared to the EC Studio. But that's no surprise, since it was the same story with efficient speakers.

    The least efficient speakers I used were 89dB, 4ohms (3 way PMC speakers) and it was driving them very well. Watch for the impedance though. From memory I remember Benchmark recommends staying away from anything 3ohms or less.

    In my experience the Studio had a bit more stage depth, but at the detriment of the midrange, which was pushed back too far to my full liking. From this pov I also prefer the 2A3MK4 vs the Studio, tubes being the same (Kron 2a3, Ericsson drivers). The AHB2 staging I found on par with the EC 2A3MK4, which in my book is awesome for any solid state amplifier. The 3d, imaging and edge precision of the AHB2 are top level, with the last 2 better than on tube amps. Driver control is beyond any tube amp I heard. Resolution I'd split as so:
    - bass, AHB2 outresolves the Studio and 2A3MK4
    - midrange: Studio = AHB2 >= 2A3MK4
    - treble: Studio > AHB2 >= 2A3MK4

    I can't comment on Vidar, but I've been dissapointed by any Schiit amplifiers in the past, so I don't have a lot of urge to get out of my way to loan one these. Perhaps one day when I get bored. A pair could be more interesting, since they can be bridged and that should take care of that low channel cross.

    I think I mentioned this in another thread, but the results out of the AHB2 are going to be dependant on upstream. Watch out for source chain, preamps, connectivity ... all that good stuff. I suspect for many people the source and preamp chain will limit the AHB2. Which is a good problem to have in the long term, since most amps become a bottleneck before sources do. If I was mainly using a TT, I am not sure the AHB2 would be my first point of call. I don't think it is needed and the upstream might become too complex. The chain I use the AHB2s in is very simple: MSB DAC with balanced preamp modules option > XLR > 2x AHB2 on low gain.
     
    Last edited: Sep 29, 2017
  12. sfoclt

    sfoclt Friend

    Pyrate
    Joined:
    Nov 24, 2015
    Likes Received:
    317
    Trophy Points:
    93
    Location:
    Online
    I have the AS-2100 on hand and a McIntosh MC2505. The McIntosh is pretty good, but the Yamaha is better in every area, particularly soundstaging/imaging and bass. The McIntosh is bit soft in the bass, while the AS-2100 is tight, precise and powerful.

    [​IMG]
     
    Last edited: Sep 29, 2017
  13. Grahad2

    Grahad2 Red eyes from too much anime

    Pyrate
    Joined:
    Jan 26, 2017
    Likes Received:
    1,162
    Trophy Points:
    113
    Location:
    Singapore
    They (AS2100) even have a built in upgraded Loki (with individual band bypass)!
     
  14. sfoclt

    sfoclt Friend

    Pyrate
    Joined:
    Nov 24, 2015
    Likes Received:
    317
    Trophy Points:
    93
    Location:
    Online
    I use the tone controls all the time. They have a good implementation. The balance is what I use the most though. Crazy how off many records are. I can balance the McIntosh as well though with the L/R gain controls.
     
  15. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    I seem to be having the opposite experience with my 92-93db Fostex BLHs (just a parallel RLC network to tone down shoutiness) and I am too scared to put the AHB2 on the 108db+ efficient Oris / Lowther horns (just a paper-oil C for lowpass on the horns - bass is active) for fear of being even more disappointed. As it stands right now, the AHB2 is so far away from my custom parallel 45 amp (and Vidar) with the Fostex that I didn't even bother. (To be honest, I'm more inclined to compare downward to the Crest CA2). Yes, the SS amps (Vidar and AHB2) have more precision in the bass, but everything else is so far behind - especially microdynamics and plankton. In my case, the AHB2 seems to be the limiting factor, even running the purest chain of just a stepper for volume (I have a bunch of 4db steppers around). And as far as the other preamps, the Freya gets in the way a bit, making the results closer, but the Saga doesn't.

    I mean, I'll give it a shot. Right now, the horns are being powered by the $200 10W Class A JLH69 amp (very lightly modded) I got from AliExpress. I'll swap that with the AHB2 and see what happens.

    I don't really understand why a TT would not be ideal. Do cartridges or phonostages make the circuitry inside the AHB2 to go beserk or something? I can try my tweaked Gungnir Multibit or Yggdrasil. Maybe AHB2 will sound better with the lesser digital sources.
     
    Last edited: Sep 29, 2017
  16. sfoclt

    sfoclt Friend

    Pyrate
    Joined:
    Nov 24, 2015
    Likes Received:
    317
    Trophy Points:
    93
    Location:
    Online
    [​IMG]
     
  17. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    I'm shipping this out to @atomicbob on Monday. Anyone is free to drop by this weekend at my place to listen and try out and directly compare another six to seventeen permutations.
     
  18. Negura

    Negura Friend

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    180
    Trophy Points:
    43
    Location:
    London, UK
    - A low noise, high DR (digital) source (ideally that also sounds good ha ha) would be a great example. Ideally I'd go a level or two higher than Yggdrasil and even more so Gungnir Multibit. Yggdrasil might just be enough though. Although I had the Yggdrasil around a while ago, since I don't have a stand-alone preamp closing in on the performance of either Yggdrasil or AHB2 I didn't try it. Some others did use this combo so could comment better than me.
    - Finding a high performance preamp is very difficult in its own right. I don't trust the Schiit ones, but that's me based on the Ragnarok and another amp or two that I found awful as preamps.

    If you don't hear the AHB2, preferences aside, at least on the level of the 2A3 amps, I think something is amiss. My money are in the upstream to it, as I don't think the speakers mentioned at least based on what I know about them should be a challenge.
     
  19. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    I actually never owned or listened much to the 2A3mk4 amps (with the Hammond transformers I assume).

    The reason I strongly doubt upstream / preamp / source are playing a factor is because in my comparisons, the only that I have changed is the amp. For instance, when I swap out the H2 with the Vidar, I lose some stuff. And when I swap out the Vidar with the AHB2, I lose some stuff.

    Also, when I use less transparent more colored preamps like Freya active, and do the same swap, I lose less, but I still lose. It stands that if preamps are the factor (removing musical information), then this effect would also apply to the other amps such as the Hegel H2 or Schiit Vidar. But it does not.

    In terms of my use of passive attentuators, that's pretty much what MSB is doing with their built-in preamp module. I doubt the passive is a roadblock. In cases of impedance mismatch*, a passive will sound soft and mushy. In addition to the steppers I have, the Schiit preamps also do have passive mode. Very easy to check how the active circuit might color the sound. I mean, I could drive over to @brencho's and borrow his $5000 EAR preamp.

    Maybe with more expensive gear, we could put these doubts to rest?
    Maybe I have a broken unit?
    Maybe the price differentials are causing some incredulity?

    *Extremely unlikely in the case of the AHB2 with its input impedance of 50k ohms. The Vidar at 22k ohms and H2 at 10k ohms (balanced) are going to be tougher for passives, depending upon output impedance of the source.
     
    Last edited: Sep 29, 2017
  20. itsikhefez

    itsikhefez Acquaintance

    Joined:
    Oct 17, 2018
    Likes Received:
    87
    Trophy Points:
    18
    Location:
    Seattle
    Apologies for the resurrect here (putting the info here in case it could help someone thinking about the AHB2).

    I didn't read everything thoroughly but it seems like the AHB2 was auditioned with a Saga ? That would be one of the worst preamps to use with the AHB2 which requires a high-gain signal (9.8Vrms) to drive it properly. The Saga has 0 gain...The Freya would not be a great choice either.

    From Benchmark website:
    LOW GAIN FOR LOW SYSTEM NOISE
    The AHB2 is a low-gain design. Maximum output is not reached until the balanced inputs reach +22 dBu. This is a much higher signal level than is used at the input of most power amplifiers. High interface signal levels are required to achieve the best possible system signal to noise ratio (SNR). Most power amplifiers have far too much gain and consequently they suffer from poor noise performance. The AHB2 is 10 dB to 30 dB quieter than some of the very best power amplifiers on the market. A rear-panel gain switch can be used to set the AHB2 at higher gain settings if necessary. The low-gain setting is designed to interface directly with Benchmark DAC3 converters and other professional audio products.
     

Share This Page