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Benchmark Audio DAC3 DX and AHB2 amplifiers Review

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Aesthetics and build

There is not much to say for the aesthetics of Benchmark products except that they are tidy, studio worthy in appearance and diminutive. They also, mercifully, are lightweight. One can carry the stack of all three together and not suffer a hernia, which is worth considering in a community of aging audiophiles. Benchmark offers silver and black facades on the DAC and amp.

The build of the DAC3 DX and AHB2 Amps is sufficient but not ultimate. The casework on the DAC3 DX is not robust enough to confidently lean a hand on while placing cables, but the amps are tougher. The DAC3 DX is so light that when I connected the Clarity Cable Organic XLR Interconnects their tension from their stiffness lifted the unit off the equipment stand! I guess you could call that air isolation; I called it a lightweight, and put a beanbag weight on it to keep it down. If the Benchmark components were judged by the old “weight principle”, the heavier the better performing, they would be deemed poor. That was a rule meant to be broken; don’t judge this component by its weight, or you miss a heavy hitter. The DAC3 DX does get warm to the touch when left on for long periods of time. In fact, when left running it was warmer than the AHB2 amps! I had no concern about excessive heat, however, as the unit was on a hard surface and not enclosed in a cabinet. I would not place the DAC3 DX into a cabinet and leave it running.

If you think that the mass of the chassis dramatically impacts the sound, then you will also be disappointed in the DAC3 DX. I don’t think high mass products would necessarily pass my law of efficacy. Typically, whatever is in the signal path directly is far more important to me, including cabling, than the chassis. The one exception I have encountered seems to be the TEO Audio Liquid Pre, which uses runs of its proprietary liquid conductor inside, reasonably argued to need extreme isolation from an overbuilt chassis.

A few comments on operations relates to the aesthetics and appearance of the DAC3 DX. It is helpful to the inquisitive audiophile to have both the word length (in bits) and sample rate (frequency in kHz) of a digital input signal indicated by the blue LEDs on the face of the unit. With use, only a glance at the indicators is necessary to ascertain their meaning. Similarly, the Power, DIM (reduces output by 20 dB) and Mute buttons reside next to each other, but on a horizontal plane to distinguish them from the digital information indicators. Perhaps a future version of the Benchmark DAC can incorporate a randomly generated pink LED which would appear anywhere on the indicators to keep things exciting, especially if it were not mentioned in the Owner’s Manual. I jest. Just checking to see if you, dear reader, are still awake.

The AHB2 Amplifier in appearance is rather like a prototypical Class A/B design shrunken to half-size. The faceplate exudes confidence and is relatively uncluttered for the amount of configurability the amp possesses. Rounded heat sink fins protect against snagging clothes or pricking fingers. Only from the back does the amp look busy. Manufacturers will never condone stacking amps, but the AHB2 runs cool enough that it would be tempting. It hardly feels warm to the touch, even after hours of use. I leave the DAC on because it is synced to the source, but the amps I turn off when not in use because I do not detect change in performance from warm up. Do not expect a solid-state amp with 0.0001% distortion to wander in terms of sonic character.

As to the remote control volume knob, it is not illuminated, I presume because one does not need an LED on a volume control at a studio console. Sitting 14 feet from the equipment rack I could just barely make out the red dot on the control when wearing my glasses. Perhaps Benchmark might consider a pinpoint light in future models. The volume control’s movement is smooth and graduated smartly, ramping up sensibly that regardless of the amplifier used I did not encounter “level explosions” from grossly, inappropriately set volume. However, less nimble-fingered users may find the speed of the control too quick for their comfort. An internal adjustment on the output might be in order (see below).

While I am discussing the volume control, “Hybrid Gain Control” is the name given to Benchmark’s combination of active analogue/passive low-impedance attenuation/32-bit digital gain structure with final servo-driven volume control. The clearly laid out, non-illuminated Remote features the controls found on the unit’s front panel. The Manual clarifies, “… digital inputs never pass through an analogue potentiometer. Digital inputs are precisely controlled in the 32 bit DSP system.” In this respect, the DAC3 DX rises to the level of an actively crossed speaker system, bridging the gap between a noisier preamp and a full-blown active speaker setup. In terms of listening, the preamp function of the DAC3 DX was exquisite, as commendable as the finest big buck preamps I have used. I concur with Benchmark’s assertion that the hybrid gain control preserves dynamic range.

Massive configurability is the name of the game 

The DAC3 DX and AHB2 Amps, in terms of their features, are inversely proportional to their scale. Again, I do not recall that I have seen more connections and switches jammed into such economical real estate. That does not account for the internal switches offering further adjustments! I’m not joking; as studio-worthy components these products are widely configurable.

As an example, the DAC3 DX offers internal gain jumpers to adjust the output of the headphone jacks, as well as Low Impedance Output Pads which (settings 0, 10 and 20) allow reducing the XLR output level to amplifiers and other downstream devices to maximize system signal to noise ratio. Without going into the unit one can also bypass the volume control, select USB 1.1 or 2.0, choose between system muting or non-system muting headphone jacks. Note: on the HGC and L versions, the D5 (digital coax) can be set for a digital output, allowing for digital pass through of the signal.

As regards the AHB2, it also has high configurability for an amp. It can be run in either Stereo or Mono mode (requiring 2 units), has three Sensitivity settings with the highest output in the uppermost position of the switch and the lowest output in the lowest position of the switch, and a choice between traditional output posts accepting speaker cables or NL4 SpeakON connectors (for both Stereo and Mono modes). The amp does not have RCA (single ended) inputs, and for that sin Benchmark has likely cut its sales of this amp. However, as someone who can shape shift systems between RCA and XLR interconnects, I much prefer the combination of options offered by Benchmark.

Regarding nomenclature on the AHB2, perhaps Benchmark would like to provide owners with a magnifying glass to read the labeling on the back of the amp. What do these people think, that everyone sits in a brightly lit studio that allows a walk behind connection of leads? Evidently so! I advise domestic users of a certain age, oh, say 50, to have both the Manual’s illustrations and a flashlight at hand when making connections. This is a product that justifies my overprotective protocol of triple checking connections.

Some of that little print on the back is very special, such as the phrase, “380W – 8 Ohm MONO.” That’s like finding an X on a treasure map! These little puppies pump out 380 Wpc into Mono! Recently I had a pair of $20K AVM Ovation SA 6.2 Monos in my room with three gain settings and they mustered only 335 Wpc into 4 Ohms. With favorable comparisons of features such as that, if you don’t have money to burn the AHB2 is an obvious choice.


Stringent words about cabling

Some audiophile companies promote the idea that their products are so well engineered that they are insensitive to audio cabling changes. Though Benchmark may not have stated it that clearly, it is certainly taken as such a company. Another one that comes to mind is Pass Laboratories. In reviewing three amplifiers associated with Nelson Pass, one of which being the First Watt J2 Amplifier, which by the way is my favorite of the three, I found all to be highly sensitive to power cable changes, despite each unit’s Owner’s Manual downplaying it. I shared this information with Nelson. However, an experience I had in ABX testing with amps shed lights on how Nelson and other designers might’ve arrived at their conclusion.

One of my more daring acts as a reviewer, and one which was truly fascinating to explore, was my review of the Audio by Van Alstine ABX Comparator, a device designed to allow the home audiophile to conduct randomly generated blind trials for level matched tests between components and cables. Whereas I was able to pass double blind trials in regards to comparisons of components and even cables, the only compared devices that I could not pass in double blind testing were amplifiers. In fact, I was not even able to surpass 50% accuracy in level matched blind trials between solid state and tubed amps! I hasten to add that was the case only under test conditions; apart from test conditions, in real world usage differences between amps are quite obvious. Later I discovered that my findings while using the ABX Comparator paralleled that of Frank Van Alstine. We had not discussed the results of my trials prior to the publication of the review.

Benchmark appeals to the characteristics of cabling used in studios, including the use of SpeakON connectors and Canare Star-Quad construction of the cables. This gives the impression that any cabling which meets specifications will be fine, and that the performance of the components will not be significantly enhanced by pursuing higher end aftermarket cables. I disagree and assert that the more finely tuned an audiophile component, the more it will benefit from aftermarket cabling. I have said in the past that if a component truly was insensitive to cabling changes it would be so compromised in terms of performance that it would not be worth owning. The best components are very sensitive to cable changes and influence systems dramatically when cables are swapped. We have here a slight difference of opinion between Benchmark and myself!

Complications made extensive testing more difficult than with products not designed with the studio in mind. The AHB2 amp accepts only XLR interconnects, and professional type connections are used on the Benchmark cables, versus the standard terminations employed in most domestic audio systems in North America. Thus, I was not able to compare “apples to apples” with perfect consistency. In this instance, I determined the best route to comparison was to assess the Benchmark loom in comparison to an aftermarket loom, a set of similar cables from Clarity Cable. The wires used from Clarity were the Vortex Power Cord, Organic XLR Interconnect, and Organic Speaker Cables. Clarity now has an upgraded line called the Supernatural and offers a USB and Speaker cable. I opted for the older Organic speaker cable in comparison because, like the Benchmark cables at the speaker end, it has banana terminations.

It got ugly before it got beautiful

The DAC3 DX proved to be powerfully influenced by the power cord used on it. I was not happy to discover that the USB input is tucked so close to the 15A IEC that none of the aftermarket power cords with round plugs would fit. Either the power cord would fit, or the USB, but not both. To my thinking, this is an egregious error in component design that moves the DAC3 into the category of components with idiosyncrasies to be considered prior to ownership. This is the assessment of someone who uses cables to adjust audio systems on a nearly weekly basis. Most studio techs would slap on the stock power cord and get to work. As a builder of fine systems for the home I work in a very different environment, and I’m not going to make such a mistake, yet Benchmark gave me few options.

Thankfully, I still had in my possession some older power cords, among them a Harmonic Technology Pro-AC 10, and it has a square plug on the IEC connector. That square housing eliminated just enough bulbous intrusion encroaching on the USB port that the USB cable could be slipped in alongside it. My displeasure subsided, and copious blessings were offered for Harmonic Technology. The improvement to the performance of the DAC3 DX was anything but subtle. If Benchmark would obtain such an improvement on performance by juggling the innards they could issue a new model designated the “DXL”. If you wish to hear this Benchmark DAC3 “D-excel” version at this time you must conduct due diligence with power cords.

This was not the only issue involving power cords, as I ran into a power cord problem with the diminutive design of the AHB2. The Benchmark Speaker Cable – NL2 to Banana – 2 Pole cables are designed to be the optimum tributary for the AHB2 amp. Remember the special SpeakON connectors and Canare wire? The AHB2 is designed so that the best performance is said to happen when the SpeakON connectors and Benchmark cables are used. However, when I attempted to use Clarity Cable Vortex Power Cords with the amps in Mono mode (the SpeakOn connector is tucked right underneath the power cord receptacle), the SpeakOn connector inhibited the insertion of the larger (fairly standard sized for an aftermarket PC) 15A IEC plug! I was beside myself with disgust! Not only were most aftermarket power cords prohibited for the DAC3 DX, but also for the AHB2!

The prohibitive layout of the back of these products when it comes to connections reduces their appeal for home high-end systems. Benchmark needs a “rethink” on this issue. It’s a good thing I’m actually testing, reviewing these products as opposed to “window shopping”, because I likely would cross them off my list for being so inhospitable to specialty cables. I would be very upset as a customer had I purchased these components, only to discover they are incompatible with aftermarket cabling. You will need to assess how important cabling is to you, and whether you can find workarounds for these limitations.

The same is true about theUSB cable; its input is scrunched next to the power cord on the DAC3 DX. I keep four or five USB cables on hand at all times, as it is among the easiest ways to tune a DAC, including the DAC3 DX. In moments I can address a shortcoming in sound quality by swapping a USB cable on the fly (Disclaimer: Do so at your own risk). The change in sound quality is comparable to that of changing a set of tubes in a tube amplifier. Do not fall victim to the misnomer that simply because Benchmark products measure superbly well there is no need to pursue extreme cabling. Benchmark products operate no differently than any other components from competing brands in that regard.

So, what about that comparison of cables between the Benchmark and Clarity sets? I set up the following components and rotated sets of cables between them: Salk Audio StreamPlayer III, DAC3 DX, AHB2 Amp (two in Mono mode), and PureAudioProject Trio15 PAP Horn 1 Speaker. I began with the Benchmark cables and played three selections, as it doesn’t take more than a few songs to determine whether there exists a difference in sets of cables. It does sometimes take much longer to determine whether those differences are significant enough to merit purchase, or are holistically more pleasurable with a wide variety of music.

Here are my notes with the associated pieces of music:

Candice Springs “Novacaine Heart” – Lots of warmth; piano strikes not sharp; treble fairly subdued; sounds “tubey”; nothing as sharply defined as I recall from mixed cable sets.

Lindsey Stirling “Electric Daisy Violin”: Violin does not “pop” out in performance; good bass presence and tautness.

The Piano Guys “Batman Evolution”: Good linearity, background clean; backing vocals cleanly heard; seems to be lacking some dynamic impact.


Here are my notes when I switched to the Clarity Cables set:

Candice Springs “Novacaine Heart”: Comparison over in 1 second, from first note; Candice’s voice more resonant; bass more expressive; can hear the venue; micro dynamics and definition superior.

Lindsey Stirling “Electric Daisy Violin”: Violin has necessary bite, especially with this music; bass/LF has more punch, weight; nuances in background clearer, more delineated.

The Piano Guys “Batman Evolution”: Orchestra more convincing; piano more palpable; less midrange emphasis.


The purpose of this comparison was not to render a final verdict of the Benchmark and SpeakON technology. That would take far more cable adjustments and listening sessions than I conducted. I suspect that a group of listeners who heard the comparison between the Benchmark and Clarity cables may have been split in terms of appreciation of the cabling sets. However, clearly the Benchmark cables did not sweep the results. It is not necessary to use the SpeakOn connectors or Canaire-based wiring for superb results. In fact, I believe one reason the Clarity Cables loom was more appealing overall was because elimination of the prohibited SpeakON connector under the power cord, allowing use of the Clarity Vortex Power Cords versus the stock power cord. It’s not so hard to get an excellent performance from a component, amp or otherwise, when good aftermarket power cords are employed. This is so, even though I didn’t season the sound to preference with mixing in, say, an alternate brand’s power cord, XLR interconnect, or speaker cables. Slight derivations from entire looms of one make can provide even more appealing sound.

I suspect Benchmark is less than gleeful about this assessment of the cables, as I write to inform the audiophile of the expected performance of the manufacturer’s products. Reasonably, the DAC3 DX and AHB2 are designed to have superb measurements, and the cables are designed to work well enough. I concur; you can get very good sound with them. While the Benchmark cabling is inexpensive enough to start your audio system, do not feel constrained as though better sound through alternative cabling is unattainable. It took only one set of alternative, and yes, much more costly, power cords and speaker cables used in conjunction with the AHB2’s more traditional output posts to revise the performance. You may be content with the synergy of the all Benchmark system, but stay open to the thought that the components can perform beyond your expectations with upgrades in cabling.

I hope that it does not seem as though this review is turning into a flame of the Benchmark components. It isn’t, as I am now finished with fault-finding. My objections are confined largely to the foibles of the ergonomics, and the limitations of the cables and connections, not the performance holistically. As with other components I can more easily accept such things if the performance overall is noteworthy. Thankfully, with the DAC3 DX and AHB2, that is the case. That’s enough of the “ugly truth” according to Doug Schroeder. Let’s move on to the beautiful truth.

10 Responses to Benchmark Audio DAC3 DX and AHB2 amplifiers Review

  1. Shahed says:

    Thanks for your detailed and informative review Doug! I’m currently driving my PAP Horn1 with First Watt J2 amplifier. This pairing was inspired by your review 🙂 I’m using Allnic L3000 mk2 with great success with J2 amp. Allnic has very low output impedance and hence suitable for any SS amp.

    If you are forced to pick a favorite between Benchmark AHB2 and First Watt J2 driving the PAP Horn1, which one would you pick? This is assuming Benchmark DAC is not in the chain and some tube preamp is present before the amp.


  2. Douglas Schroeder says:

    God’s Peace,
    Thanks for the comment; it’s good to know that I inspire at least one audiophile globally. 😉

    Honestly, I like both amps quite a bit. It’s tough to not like an amp driving the Horn 1! The J2 has less dynamic power, less forward and “punch” to the sound, while the AHB2 is very, very tight, clean, and more forward and more “punch” dynamically. The tonality is pretty close between the two of them.

    The most significant difference would be the sense of space and air in the venue; the J2 would seem typically like a larger space, and the AHB2 would seem more studio-like, not in an absolute, but relative sense. The speaker would sound more laid back with the J2 and more aggressive with AHB2.

    Take your pick!


  3. Doug,
    In your opinion, how would the Mono or stereo ABH2 get on with the Sound Labs U-545s (nee’ U4iAs) that you reviewed?

  4. Dan Piekarski says:

    Hello Doug,
    Thank you for the very thorough and detailed review of the Benchmark AHB2 components!

    I have read your reviews that go into a high level of detail on both the Benchmark and Legacy Audio products and therefore am asking for your opinion on a somewhat unique audio situation.

    In re-configuring a Home Theater configuration I am considering in using a pair of Vandersteen 2CE speakers for the rear surrounds in a 7:1:4 Atmos set up.

    The Front end has 2 Legacy Focus SE mains, 1-Legacy Marquis XD center, supplied by a Legacy Power Bloc4 amplifier. Upstream from that is an OPPO player and Integra DRX-R1 receiver…
    We split 50/50 time on 2 channel music and Home Theather.

    My question regards the Amplification for the Vandersteen 2CE rear speakers, as they efficiency is rather low at 88 db, and impedance ranges from 7 ohms nominal to 4 ohms minimum..

    Doug, based on your knowledge of both product lines which amp would you choose between the Benchmark AHB2 and the Legacy Power Bloc to drive the Vandersteen 2 CE speakers? The Legacy delivers 325 Watts into 8 Ohms, 650 Watts into 4 Ohms. But the Benchmark performance reviews have been exceptional.

    Any feedback/direction that you can provide would be much appreciated!
    Thank you !

  5. Dan,
    God’s Joy to you,

    Thank you for the complement; it is gratifying when people find value in my reviews.

    You ask a question that does not have a direct answer. Either of the amplifiers would do a commendable job in driving the Vandersteens. I have done as you, in that my surround speakers are different than the mains. In my audio world HT is not THAT important (That is heresy to some who consider HT their primary source of entertainment). I suspect that value and flexibility are large considerations as you are willing to mix gear for HT.

    As such, the answer is not a simple this or that amp. The cleanness, tonality, dynamers, etc will all vary between the two amps with the Vandersteens. I could happily recommend either amp as I think they are more similar than different. They both have excellent detail retrieval and plenty of dynamic power. The PowerBloc is one class D I would recommend.

    I think you potentially have your answer in hand. Why not try the PowerBloc amp you have with the Vandersteens and see if it is suitable to you. Unless you are trying to wake the dead with levels, you won’t have any issue with that amp in driving the Vandy’s. If something is niggling, bothering about the sound, then do a trial of the Benchmark.

    One off topic recommendation; if the Oppo is your primary source, I strongly suggest you look into a music server and streamer like the Small Green Computer sonicTransporter and SONORE Signature Rendu SE with systemOPtique that I reviewed. The sound quality is sensational and convenience off the charts. I think you may find yourself listening to music much more with such a source. Personally, I do not feel that extreme expenditures are necessary in HT, as the visual stimulation seems much more important, i.e. video quality. Again, others may disagree.

    My advice is based on the perspective that functional, good enough performance for HT is a legitimate goal, as more than 90% of my investment and effort goes to 2 channel. You may feel that this is not good guidance, so I encourage you to discuss with others, too.

    Douglas Schroeder

  6. Dan Piekarski says:

    Hello Doug,

    And thank you for your pleasant reply.

    I will reconfigure the system and give that a try as you recommended. That should help rule in or out the Legacy amp. Was also able to make the trip to the Legacy plant in Springfield and they are great people to deal with.

    Read your review of the Legacy Focus SE speakers with the wavelet processor, and that may be an addition someday, but for now the Focus SE’s are very enjoyable to listen to. Currently listening to Acoustic Alchemy in 2 channel and the instrumental sound through the Focus SE’s is a real treat for me.

    I agree that the HT world is not that critical as the sound does vary quite a bit with the various video /audio sources. We enjoy family movies and having a good front end speaker system helps even more. Two very good sounding Atmos movies were the J K Rowling based Fantastic Beasts movies, and the Iron Man movies had some good sound for a Blue Ray only action movie.

    For Home Theater , the Legacy Marquis XD center channel speaker is best center channel that I have heard/owned, and the SVS Ultra 13 Subwoofer helps fill in the bottom end.

    My theory is to have a very good 2 channel system and using it for Home Theater is an extra bonus.
    Some folks do have heartburn with HT but it works very well for our family.

    Also Doug, your recommendation for the music streamer and server is very timely. I have printed your reviews and will reread them and highlight the key points. I also printed the info for the 2 components that you recommended. Having the equipment and setup to listen to high quality sound with almost unlimited titles is very appealing to someone who remembers 8 tracks and cassettes! (Haha, what on earth are those!)

    Honestly I am pretty uneducated in the world of digital, PC audio, servers and streamers. I was fortunate enough to attend Axpona the past 2 years and met Dr Aix, Mark Waldrep and bought his book and also got the book from Jim Smith called Get Better Sound.

    There are many components in that area and I have much to learn in that area. Part of the fun of Audio is the research into the various options and listening to equipment choices.

    With the weather changing and golf season winding down, audio research and education is a perfect fall/ winter hobby for me.

    If you have any other entry level advice or recommendations for the music PC/ Streaming / Servers/ DACs, etc it would be greatly appreciated!

    Thank you Doug for all of the hard work that you do!

    Dan Piekarski

  7. Dan,
    God’s Joy,

    Thank you for the encouragement and compliments; I appreciate it!
    Glad that my comments were helpful. I’m still stunned at how good the systemOptique converter from SONORE is at eliminating digital noise and allowing minutia in the music to shine through.

    Feel free to stay in touch in regards to the build out of the system.

    Douglas Schroeder

  8. Hello Doug,

    Hope that you are well.

    Just to follow up , I did take your suggestion, and wanted to provide some feedback!

    I positioned the Vandersteen speakers directly next to the Legacy Focus SE speakers and listened to some very familiar tracks on the Legacys. Next I switched the Legacy Amp source to the Vandersteen speakers and played the identical tracks several times.

    I was totally amazed at the sound coming pout of the Vandersteen speakers! Obviously I had to very slightly adjust the volume for the less efficient speakers but once tweaked in, I have to admit that those speakers have never sounded so good!
    Thank you for your suggestion!

    I did order the Legacy Power block amp and just got it in the mail this week, and am looking forward to hooking it all up!

    I appreciate your thoughts on the Sonore system and am still looking in that direction next.

    An area of interest recently in music streaming is in the one box solutions and a couple of good quality brands I have been studying are the Lumin T2, and D2 and also the Bryston BDA 3.14 , and the Mytek Brooklyn streamer is also highly regarded.
    Do you have any opinion or strong thoughts on these components?

    I have a simple recommendation for you also, as my wife listens to some music on her desktop and I Pad device in the kitchen. One speaker model that I recently purchased for her was the Vanatoo Transparent Zero. I heard those at the Axpona show and they are awesome little speakers for a desk top..

    Doug, Tank you again for your recommendation and feedback!

    Take Care!


  9. Dan,
    God’s Peace,

    I’m elated that the suggestions are working out for you. A bit of curiosity and experimentation can lead to a holistic improvement and much more enjoyment.

    I cannot comment on the sources you mention, as I have not used them. I have heard the Booklyn at a friend’s house and it performed well.

    It has been a long time since I did any desktop sound. I normally do not listen to music while on computer. I appreciate the lead, however.

    Douglas Schroeder

  10. James Romeyn says:

    I too thoroughly enjoy Doug’s reviews and find much value in them. Doug seems like someone who is eminently capable in writing user manuals for the most complex machines.

    Upon request I’ll add a detailed room/system description. Suffice to say I’m in my late 60s, a lifetime music/high-end audio business professional, the room and system are refined and revealing of changes in any cable, program or component. The room is well treated, moderately lively and NOT overdamped. The system employs at least 2 professionally designed proprietary pieces: one is a huge server/streamer with ca. 4x the power of Chord’s powerful M-Scaler, the other being a discrete passive (or active) accessory speaker solely for reverberant field energy. One of Doug’s favorites, Clarity Cable is used throughout but not quite exclusively. The system employs a state-of-the art distributed subwoofer array, an improved version of the system that TAS awarded 3 Golden Ear Awards. HP cutoff is ca. 55 Hz.

    Main speaker voltage and current requirements in this room: The main speaker is a 2-way satellite with natural rear-ported roll off ca. 55 Hz, true 90.5 dB, 9/6-ohm nominal/minimum, benign phase angle, IOW well above average on the easy to drive scale. Maximum power w/20 Hz input (below the port tuning F where the proprietary pro-sound mid-bass is unloaded) is ca. 100Wrms. Ca. 110 dB maximum clean output w/only 1 dB of dynamic compression (a constant directivity system w/proprietary wood waveguide and 1″ beryllium compression driver.)

    Coincidentally both tested amps rated 100W @ 8-ohm. (I have a 3rd amp rated 140W @ 8-ohm which did have more punch and dynamic prowess; that advantage was most audible in the mid-bass range.)

    3 persons participated in a level-matched AB test between Benchmark’s AHB2 and Atma-Sphere’s Class D mono blocks. (One amp, cannot recall which one, required .5 dB input level change which netted ca. a negligible .1 dB output difference. To eliminate sub level differences, we simply turned off the sub array.) Note the main speaker cutoff is ca. 50 Hz.

    Both amps sounded tonally neutral.

    All agreed AHB2 sounded more “accurate” and revealed a little more musical detail that the Class D could not dig out of the mix.

    But overall, all 3 preferred the Class D, with increased density of images, a larger stage in all 3 dimensions and significantly more musical flow and emotional involvement. I would say the above advantages were in equal proportion, but if I had to pick one, the density advantage might have been the biggest. Think of the best qualities of the best OTL tube amps but without the heat and maintenance.

    The Class-D provided a performance upgrade at least equal to its 80% higher SRP. Both amps are US made and would likely reflect similar price discrepancy wherever they are both sold.

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