Audio Research Reference 6SE line preamplifier John Atkinson August 2021

John Atkinson wrote about the Audio Research Reference 6SE in August 2021 (Vol.44 No.8):

Jason Victor Serinus's first impressions of this $17,000 tubed preamplifier (footnote 1) in Stereophile's November 2020 issue were very positive: "Am I really getting paid to do this?," he wrote, calling it "some of the most polished, transparent, and arresting sound I'd heard from my system." But as his auditioning resumed after a break of a few days, he discovered that the REF 6SE sounded very different than it had a few days earlier. "Much of the tonal beauty that had momentarily caused me to hold my breath remained," he wrote, "but the shiny polish and transparency that had knocked me over was gone."

After some investigation, JVS found that the REF 6SE was very sensitive to system tuning. "The essential building blocks—the components—remain unchanged, but the context in which they are presented brings out their magic," he wrote, adding "What was formerly 'really good hi-fi' blossoms into an audiophile bouquet." Once his system had been optimized, JVS was able to conclude that the Audio Research REF 6SE "is a bouquet with a fragrance all its own, one that you may well find irresistibly seductive. If you want to hear all it has to offer, pay particular attention to context, and give it all the attention it deserves."

Given the unevenness of Jason's reviewing experience, Editor Jim Austin felt that a second opinion was called for. Accordingly, Audio Research shipped the review sample, serial number 52307, back to Stereophile so I could take a listen.

Other than my Roon Nucleus+ server, with its HDPlex 200W linear power supply, and an AudioQuest Niagara 5000, with which I condition the AC for the power amplifiers, the system I used to audition the REF 6SE had nothing in common with Jason's. Digital bits were converted to analog with a network-connected MBL N31 processor, which was connected to the Audio Research with 2m lengths of AudioQuest Wild Blue balanced cable. The preamplifier's balanced output was connected to the two Parasound Halo JC 1+ monoblock amplifiers with 3m lengths of Wild Blue interconnect. Loudspeakers were either my long-term reference KEF LS50s or new samples of the GoldenEar BRX I reviewed in September 2020, both pairs sitting on 29" Sanus stands.

The REF 6SE's balanced output impedance was 669 ohms at 1kHz and 20kHz, rising to 1394 ohms at 20Hz. There were thus no compatibility issues with the Parasound amplifiers, which have a balanced input impedance of 92k ohms at low and middle frequencies, and 89k ohms at the top of the audioband.

Speaker cables were AudioQuest K2—while I am by no means a tweak fanatic, these cables were raised above the carpet with AudioQuest Fog Lifters, and both the MBL and the Audio Research components were supported on Ayre Myrtle Blocks. The server's power supply, the DAC, and the preamplifier were plugged into an AudioQuest Niagara 1000 conditioner. Although the preamplifier's display indicated that its tubes had been used for 372 hours, I waited for another 36 hours with the REF 6SE being powered up before starting my critical listening.

Before I installed the Audio Research preamplifier in my system, I had been using the MBL N31 to feed the Halo JC 1+ monoblocks directly, using its volume control in Roon set to a maximum of –17dB for most recordings. The MBL's volume control was set to the maximum for use with the REF 6SE. With its volume control set to the maximum, "103" on the display, the REF 6SE's voltage gain from its balanced inputs to balanced output is 12dB. The control steps are around 0.3dB, meaning that the unity-gain setting is "62." However, the system had too much gain, so I set the Parasounds to Low gain, equivalent to 23dB. I listened with the Audio Research's control mainly set to "31," ie, attenuating the MBL's analog output by close to 10dB.

The reason I have examined my system's gain architecture in detail is that the measurements that accompanied Jason's review indicated that at this volume setting, the REF 6SE offers vanishingly low levels of noise and distortion. The latter is predominantly second harmonic, which is subjectively innocuous even at a level 100× greater than that in the REF 6SE's output.

It might reasonably be expected, therefore, that the Audio Research preamplifier will be transparent to the source.

In this respect, the REF 6SE ($17,000) was no different from the last three high-performance preamplifiers that had passed through my system: the MBL N11 ($14,600), the Pass Labs XP-32 ($17,500), and the Benchmark LA4 ($2599). The measured performance of all four preamplifiers implies that audible defects are unlikely. Yet the three other preamps did sound different from one another, something that continues to disturb this measurer's sleep. The MBL N11's tonal balance was slightly warmer than that of the Pass Labs XP-32, the Benchmark LA4's presentation a little more forward. All three were champs at retrieving recorded detail, though the soundstage reproduced by the LA4 had a little less depth than with the other two. And the aspect that most puzzled me was that the MBL's presentation of acoustic objects within the soundstage was a little more palpable than that of the Pass Labs and Benchmark.

So how did the Audio Research REF 6SE sound? As Jason described in his review, its presentation of recorded detail was superb. I hadn't played Kavi Alexander's recording of Gary Woodward performing Prokofiev's Flute Sonata (16/44.1 ALAC file from Poem, Stereophile STPH001-2) for too long a time. However, triggered by writing As We See It for this, the magazine's 500th issue, I cued up this first recording on the Stereophile label in Roon. Speakers were the KEF LS50s.

Thanks to the accurate amplitude-stereo imaging captured by Alexander's Blumlein miking, I was transported back 32 years to USC's Allan Hancock Foundation Auditorium. The heroic arpeggios on the centrally placed flute in the final movement could be heard lighting up the hall's acoustic, and the realistically sized, harmonically rich New York Steinway piano, with Brooks Smith's empathetic accompaniment, was set halfway across the stage behind the flute, this clearly revealed by the Audio Research's transparency.

Turning to a classic recording, "Three to Get Ready" from Time Out (DSD64 file, Columbia/Analogue Productions), Dave Brubeck's piano is panned hard left and Joe Morello's drums hard right. But with the Audio Research preamp in the system, I could unambiguously perceive the reverb excited by both instruments and placed in the center of the soundstage. I had intended to listen to just this track from Time Out but ended up playing the album all the way through, always a sign that something good was happening.

Changing from the KEF speakers to the GoldenEars, I followed the Brubeck album with another modern jazz favorite, Charlie Haden and Jim Hall from Live from Montreal International Jazz Festival (24/48k MQA FLAC, unfolded to 24/96k Impulse/Tidal). Thelonious Monk's "Bemsha Swing" opens with Haden soloing. His double bass hung in space between the speakers, its sound superbly well-resolved, with excellent pace. (Haden always had a great sense of time.) Curious about the effect of the MQA encoding, I switched to the 16/44.1 version in my Roon library: Ah, not the same mix. The double bass was louder and richer but with less of a sense of flow. The REF 6SE was clearly stepping out of the way of the differences in recordings, and it preferred the lighter tone of the MQA file.

The MBL and Benchmark preamplifiers have long since been returned, but I still had the Pass Labs XP-32 on hand. With levels matched to within 0.1dB using the 1kHz, –20dBFS warble tone on my Editor's Choice CD (Stereophile STPH016-2), the Audio Research's presentation was more upfront than that of the Pass Labs. A favorite Bruce Hornsby live album, Noisemakers Summer 2007, was only available as a 256kbps MP3 download, but even with the lossy compression, the band rocks the music mightily, especially the medley of "Fortunate Son" and "Comfortably Numb." Even though it was actually 0.07dB louder at 1kHz, the XP-32 sounded a little quieter than the REF 6SE on this track. Repeated listening indicated that the Pass Labs preamplifier wasn't actually quieter but that everything was laid a little farther back in the soundstage. Paradoxically, the rear of that soundstage—the occasional audience noise—wasn't as distant as it had been with the REF 6SE.

The Audio Research preamplifier's presentation was more robust-sounding, especially in the midrange. With the REF 6SE, Paul Desmond's alto saxophone on "Take Five" from Time Out and Arturo Delmoni's violin on his lyrical if leisurely performance of Brahms's Violin Sonata No.1 (16/44.1 ALAC file, ripped from John Marks Records JMR2) were both pushed a little forward in the soundstage compared with the XP-32.

And while the Pass Labs' lows were better defined—the kickdrum on the Brubeck and Hornsby tracks had more attack—Charlie Haden's double bass had less body than it had with the Audio Research, this evident with both the MQA and the plain 16/44.1 playback.

Which preamplifier I preferred depended on the loudspeakers I used. The lighter-balanced treble of the Pass Labs worked well with the KEFs, which tend to be a touch mellow-sounding. By contrast, the Audio Research's somewhat softened highs—Michael Fremer had written about the original REF 6 that "shimmering cymbals sounded somewhat muted"—proved to be a better match with the GoldenEars.

So, did the Audio Research Reference 6SE's sound change during the five days I had it in my system, as it had chez Jason? No. Its presentation was consistent from the beginning of Day One to the end of Day Five. However, I believe its sonic signature will work best with systems that are a little laid-back in the upper midrange and that don't have underdamped or poorly defined low frequencies.

But, as to why the REF 6SE sounded the way it did in Jason's system, I don't have a measured clue.—John Atkinson

Footnote 1: Audio Research Corp., 6655 Wedgwood Rd. N, Suite 115, Maple Grove, MN 55311. Tel: (763) 577-9700. Web:
Audio Research Corp
6655 Wedgwood Rd. N, Suite 115
Maple Grove, MN 55311
(763) 577-9700

CG's picture

This beggars the obvious question - Which provides the magic? The setup or the gear?

Certainly it's a combination, but is setup undervalued? It reads to me like the system setup for Jason was roughly as significant in defining the sound quality and appeal as the new preamp. Perhaps I'm reading a lot into this, but what's going on? Is this like cooking, where the preparation and the seasoning often matters as much or more than the raw foodstuffs?

I've often marveled at how enthusiasts are willing to buy preamp after preamp, as one example, but will not even consider adding modest acoustic treatment of their listening quarters. Is that really sensible?

One famous owner of an equally famous cable company spoke many years ago in Stereophile how the selling prices of his products were based on the magnitude of sound improvement brought by using those cables over others. The actual cost of the product for him and the rest in the supply chain was irrelevant. If a certain cable made as much improvement as jumping to a three times as expensive amplifier, shouldn't the pricing for that cable be the same as for the amplifier? Whether you agree with that pricing philosophy or not, and it certainly has fanned some of the flames associated with the cable argument, there must be some basis in the results since people continue to buy more expensive cables. Herd mentality?

I'm not offering an opinion here. Merely asking.

Allen Fant's picture

Bravo! JVS
I really enjoyed the introduction leading into this gear review.
A Reference System + Equally Good Music = Happiness! Simple.

latinaudio's picture

... your article dismantles all comments directed to overvalue the relative low cost and high quality of the Benchmark LA4. It's a good device, but it's "light years" behind the best despite its flawless specs.
I'm tired of reading from objectivists that Benchmark products are "supreme" just because JA achieves excellent results when measuring them.
Audio Research, Dagostino, Ayre, DCS, etc. are out of my reach, but from what you and other reviewers have expressed they undoubtedly sound "in another league". So no: the Benchmark products are not what its fans say they are: cheaper yes, but better never...

Kursun's picture

Yes, the more money you pay sweeter it gets, for some!
As a matter of fact, overpricing is a well known marketing strategy as a bait for those people.

latinaudio's picture

If it sounds better it's simply better, what else is it about when we evaluate equipment? If it´s more expensive isn´t necessarily better (PMC fact.8 signature comes to mind).
Until the day you know what to measure exactly (and how to do it!)you will have to trust your ears absolutely. Like the ones from the stereophile reviewers, which is why I assume everyone reads this magazine, or not?

Glotz's picture

... Does not dismantle the other reviews that this and other magazines provided.

You rush to negative conclusion in the same way others rush to praise it.

What about the amp's input and output impedance mismatches with the LA4? JA specifically addresses the good match for the ARC Ref 6SE with the D'agostino, but does that imply it's also a good match for the LA4. Dubious.

While I do agree the objectivists are largely full of it, and on this site they have too overhyped various components in the line, but does it mean that JVS was 'correct' in his dismissal of the preamp to the others?

What about the additive nature of the Ref 6SE? The treble and bass in particular have been addressed over time and tailored. Is that less accurate as a result? Yeah, probably. Does it matter to great sound? No. It sure don't!

I have heard this preamp for about an hour with 160M's with equal gear in a well-set up dealer's system, with great a great LP playback in tow.
I love it!

But that doesn't necessarily mean that the LA4 is worse or less accurate, just different, and different in JVS' system. He, rather, decided to make over-arching claims that the king has no clothes and referencing JGH and others.

I prefer if on the other more 'subjectivist' end of the spectrum we would ease up on the pronouncements that so well polarize audiophiles, or at least refrain from pure 'finality', when the job is to report on what one hears...

tonykaz's picture

It's a nonsense question, isn't it?

A person must discover the totally unique creature that they are.

It can take decades to purge cultural norm guidance.

Once someone stops being the person someone else demanded, life begins it's wonderful and exciting journey.

No-one is a Black Sheep, the people saying Black Sheep are the problem.

Be the unique person you are and celebrate life, everyone will stand with you. ( even if you're a trouble-maker like me )

I've always been pulling for you.

Two thumbs up

Tony in Venice

doug beechwood's picture

So the unexplored question here is... why is there a 20A IEC power connector on a preamp that draws 130 watts? And what connector is on the other end of the supplied power cord; a 15A or a 20A?

The specs shows the unit suitable for operation at 240VAC. Does this mean it has a switching power supply?

I'm awaiting delivery on 290 lbs. of an air conditioner & furnace. Installed by others, with a city building permit, and a 3rd party HERS test. Painfully expensive, but still $7000 cheaper than this item.

stereosnarf's picture

I've owned several pieces of ARC gear and they are great, but...

It really is all about the sum total of all the components and it's tough to know in advance what plays nicely with what. A mismatch of just one component can leave you feeling cheated.

An example; I own a Parasound JC5. I also auditioned the A21+. They are great amps... until you hook them up to a Magnapan speaker. That pairing is awful. The bass shrinks dramatically and the highs bloom a bit too much. Switch over to some cone-driver speakers (Ryans) and suddenly all is well. The difference is stunning. I can drive the Maggies with ARC or Manley gear and the Maggies and Ryans sound much more similar.(and great)

In that light, it's even easier to understand why manufacturers want you to use their components throughout your system. Theoretically, all mismatch has been eliminated.

tonykaz's picture

ARC was the most desirable Audiophile Brand.

I owned a few pieces and thought it was over rated but it had a nice industrial feel for owners.

Conrad Johnson, that I represented, was also over rated ( in my opinion ).

Today I wouldn't own either brand at eBay prices, much less new prices. ( I will buy at Yard Sale prices for resale ).

A person gets Bragging rights with ARC and pricy replacement tubes.

Still, ARC stands by all their stuff, no matter how old. Gotta love 'em for that.


I miss my local ARC Dealer, Harry Francis of Audio Dimensions in Birmingham, Mi. Hello Harry if you are reading this, I wish you were here in Venice-- I'll buy you a nice Sea Food Dinner at Sharky's when you're in town !

Tony in Venice

JHL's picture

...tinged toward negative personal anecdote from the past that dings the integrity of manufacturers or the choices of listeners isn't as pertinent as commentary on the real sound and owner feel of contemporary equipment.

It's free press. Commenters should remember the topic and show some appreciation for the effort to produce it.

tonykaz's picture

Accurate phrasing for sure.

I buy and sell this type of gear on the regular. ( eBay and elsewhere ).

My opinions are based on personal experience ( decades of personal experience ).

My 'Value for Money' equation is the main ingredient colouring my opinions that I'm able to share, they are just as valid as your opinion of my writings.

I share my Price Tranche philosophy with Steve Gutenburg's comfort level in pricing.

Super pricy gear deserves plenty of extra scrutiny and disapproval when justified.

ARC's integrity is outstanding, their dealers are typically outstanding.

Owner Feel is real for ARC, I agree.

ARC's Value for Money is supported by the outfits continuing Service ( for a hefty price ).

ARC has a kind of Aston Martin luxury positioning in the Marketplace.

I'm always happy to buy another ARC piece, I've just never had one that stood out as a keeper and I'm a little suspicious of reviews touting an ARC piece in the Concluding comments. ( which I suspect the reviewer MUST write )

Tony in Venice

ps. if you own an ARC piece, share your performance evaluation experience.

ps 2). the high MSRP Retail Price of this piece is what drives support for the higher used prices of ARC gear.

JHL's picture to string that all together to reflect or expand on the article but you're right that opinions happen. Some hew closer to pertinent reality than others too, which if we're on about sound and hardware, helps.

tonykaz's picture

I've never owned any piece of Audio Gear that performed as well as a Magazine Reviewer reported. I attribute it to Manufacturers carefully selecting pieces to send to magazines. Typically, any two ARC SP 6b's will sound different. Certainly, the Conrad-Johnson Premere 1 Amps, I sold, did not sound like the reporting that Tony Cordisman did on the original review sample ( a rave review ), the new ones I sold ( as a full line dealer ) were not wonderful in any way. ( the MV-45a was the Pavaratti of the Conrad-Johnson range ).

Tony in Venice

JHL's picture

...that about the only way I can, which is as an opinionated negative anecdote from the past with a side of projected manufacturer incompetence.

How it reflects on JVS and the 6SE is unknown.

tonykaz's picture

Jason just wrote his best piece yet, he's a unique person with something to say.

ARC is ( as far as I can tell ) a wheezing Dinosaur, attempting to recapture the illusive Bill Z's tremendous success.

Magnapan, on the other hand, remains the Outstanding Audiophile Contributor from the frozen north of Minnesota.

My opinions, only!

Tony in Venice

JHL's picture

...are a lot of great engineers and a lot of entirely competent manufacturers.

Given that neither original company or chief engineer remain, and given that you're projecting intent against type, how does criticism follow?

tonykaz's picture

Audio Gear priced at Automobile price levels leaves the gate wide open for generous criticism.

The gear should sound outstanding but it typically doesn't ( my experience ).

You can critique me for being critical, if you like.

Being an Audiophile is all about discrimination and critical evaluations.

Plus, there is plenty of room for differences of opinion.

I like ARC for it's ability to attract buyers not for it's sonic performance.

so, I buy ARC at the right price and sell.

Tony in Venice

JHL's picture

...more followup about ARC or its engineers or purported values then. An improvement over imagining them.

I imagine a world in which comments threads trailing free editorial content apply to better sound and camaraderie, not asserting a corporate ethic or quizzing the guy taking the gear home or the socio-economic failings of whomever. John Lennonists will appreciate that stereophile's utopia.

tonykaz's picture

I imagine a world of wonderful music not based on pricy.

All of us are peaceable comrades with unique and valid opinions.

We have a passion for our little niche hobby, mine has been lifelong.

I also have a certain love for Stereophile and JA1 since his HFN&RR days, I don't subscribe or read the other Audiophile Glossys. Stereophile's Editorial Content Percentage is the largest of any Journal I'm aware of. ( I do follow the Audiophiliac on YouTube, of course, and miss Mr.Dudley & Tyll )

Stereophile attracts the intellectual vein of Readership and commenters with it's outstanding Editorial Guidance and mostly verbose & poetic reviewers.

Stereophile is "Home Sweet Home" for Audiophiles Globally.

Tony in Venice

MatthewT's picture

Ever get boring and repetative to write? It does reading it.

"I'm always happy to buy another ARC piece, I've just never had one that stood out as a keeper and I'm a little suspicious of reviews touting an ARC piece in the Concluding comments. ( which I suspect the reviewer MUST write )"

gtaphile's picture

I own ARC 6Se and Phono 3Se currently. Had 5SE and Phono 2 prior.

Before deciding on 6 series and Phono 3Se I tried other brands of higher cost. CH Precison and Luxman for example and they did not integrate as well and although performance was better in some areas and about equal or slightly less in others overall the imaging was vastly inferior and the top to bottom tonality was MIA. So my take away - it's very difficult to improve upon an ARC front end synergy by inserting another brand. Are they worth the money? They are to me.
Gary from Venice Florida!

teched58's picture

Seeing your (tonykaz) sig, all this time I thought you were in Venice Venice (i.e., Italy). Who'd have thunk it's actually Florida!

tonykaz's picture

Florida is Quality of Life!

Venice Italy is history !

Venice Florida is an incubator for old people, swimming in the pool, year round sun shine, rainbows weaving thru shades of gray rain clouds, fresh seafood at the Amish Market and very little culture.

Italy is thick with the Cultural Civilization of my ancestors.

I have a Colnago Master lite steel bicycle hanging in my office, it's as close as I'll probably get to living in Italy. ( from the Eddy Merckx era )

Tony in Venice

FredisDead's picture

JVS is no doubt a very nice guy. But IMHO his talents lie in show coverage. His reviews are often too much a personal pursuit and a reflection of himself rather than the subject of his review. It as though where you, me, and all of us would look at the subject of this review and see an ARC Ref 6SE, he is looking at a mirror. The new editor made a mistake. This review should have been assigned to Mike so that the rest of us could read something meaningful, particularly if we want to know the qualitative difference between the Ref 6 and Ref 6SE.
This review is absolutely worthless. In fact, it is outright painful to read.

tonykaz's picture

I've been overly harsh too.

I need to soften up.

I'm blaming my anger on what the donkeys did to my Bernie.

Oh well, moving on.

Sorry isn't strong enough.

Tony in Venice

gtaphile's picture

I wish the review samples of these hybrids would include NOS replacement tubes as part of the kit. In my opinion having played with all aspects that one should play with (power conditioning, PC's, IC', equipment stand, footers, room treatments etc.) to optimize the preamp, the NOS changeover is the largest improvement. Clearly the opaqueness is lessoned as well image focus is improved.

ejlif's picture

I don't see the point of reviewing a preamp when you are digital only and running a DCS system known to be just as good if not better than running through any preamp at any price. If you have multiple sources and need switching then you are stuck with having to use a preamp but digital only, no preamp is a no brainer unless you just want to spend more money. The cables alone used are more than the cost of the preamp. 30K + for a marginal improvement and possibly worse sound is not much of a sales pitch.

Jason Victor Serinus's picture

that your statement is not true. dCS never claims its volume control is the end-all, be-all. If it did, it would not display with preamps from other companies at shows. Regardless, even if the dCS volume control were superior to every possible preamp design, it would still make a useful base point for comparison.

ejlif's picture

it is made clear by your review that a spending an additional 30K may get you nothing and if not worse sound maybe. It seems that most reviewers of DCS say ditch the preamp. I have a Rossini and clock but never had preamp with it. I'd like to add vinyl but just to much to try and find a preamp that will not actually degrade the sound of the Rossini. I think I'd go for an AD converter and phono pre before going to a regular analog preamp.

Jason Victor Serinus's picture

Glad to learn that you're asking based on personal experience. While the AR preamp definitely costs less than $30,00 - it's under $20,000 - the preamp I now use with my Rossini DAC/Clock combo is the D'Agostino Momentum HD preamp. It's more than $30,000 - $40,000 to be exact. Please see my review. I never cease to be amazed by this baby. It heightens color contrasts, but not in an exaggerated way; enlarges images in natural proportion; and is a monster when it comes to bass. It's also as smooth as can be. I had heard it with the Vivaldi stack at at least one store demo and perhaps a show before it came to me for review.

Ortofan's picture

... "heightens color contrasts", "enlarges images in natural proportion" and "is a monster when it comes to bass", is this device somehow extracting additional information from the input signal or is it creating these artifacts?

Is it simply a preamp - as in providing gain, volume adjustment and input switching functions - or is it additionally performing some sort of processing function to subjectively enhance the audio signals passing through it?

Jason Victor Serinus's picture

Your comment presupposes that there are absolute colors and image sizes on a recording, and that any preamp that, in contrast to other preamps, enlarges images, heightens contrasting colors, and transmits more bass information creates artifacts that are the results of "processing" and "enhancement." I would argue instead, based on what I hear, that the D'Agostino Momentum HD preamplifier moves reproduction one step closer to the real thing.

Take, for example, Seattle Symphony's recording of Richard Strauss' Also Sprach Zarathustra. I attended one of the two performances from which the live recording was assembled, and sat 8-10 rows back. There is no way that my Alexia 2s and the rest of my components, in my 16 x 20 x 9 room, can reproduce the sheer volume of the instruments that created the huge, glorious sounds I heard. My system can't move as much air, and if I turn the volume higher in an attempt to do so, I overload the room and potentially damage my hearing. The D'Agostino Momentum HD preamp moves me one step closer to what I heard compared to any other preamp I've ever used in my system, or what I hear when I rely on the dCS Rossini DAC's volume control. It takes me one step closer to the truth of my actual experience.

Having used the now departed from Serinusland dCS Vivaldi DAC in my system, I know that if I had it in my system instead of the Rossini, images and bass would be larger and weightier, colors would be even more saturated, and instrumental textures and the contrasts between them would be more palpable. Is the Vivaldi, in turn, adding information, bits, artifacts, or whatever you might wish to call them? Is it enhancing the signal? I would suggest instead that it enables me to hear more of what's on the recording. To my ears, the D'Agostino Momentum HD preamp does the same thing.

Ortofan's picture

... wasn't the Audio Research Reference 6SE the subject of the discussion?

Nevertheless, the question remains as to what aspects of the transfer function of a preamp (D'Agostino Momentum HD, or otherwise) might possibly account for its purported ability to allow a listener to subjectively "hear more of what's on the recording" than when it is not in the system?