Rogers High Fidelity 65V-1 integrated amplifier

"Okay, all you high-rolling audiophile know-it-alls—what is the argument against amplifiers that operate in high-bias, class-A, single-ended mode, with the lowest possible parts count? Is there a better strategy for beauty, rhythm, color, texture, and easy-flowing musical verity? I think not. And please explain: Why has mainstream audio gone to such ridiculous and expensive lengths to avoid building and selling precisely these sorts of amps?"

It was I, your humble prattler, who in October 2016 posed that rhetorical question, in my review of the First Watt J2, a 25Wpc power amplifier designed by Nelson Pass.

Now I'm reporting on another class-A, single-ended amplifier, this one really low-powered. The 65V-1 integrated amplifier ($4000) uses EL34 or KT88 pentode tubes—at the time of purchase, the user specifies his or her preference—and is made by mainstream manufacturer Rogers High Fidelity, in Warwick, New York. Rogers's president and chief designer, Roger Gibboni, has obviously gone to extreme lengths to create a unique-looking integrated amplifier with an old-school finish of black crinkle paint, a tiny purple display, and an entirely new-school iOS control app for iPads that, among other things, uses Bluetooth connectivity to display the 65V-1's power output on a virtual VU meter on the iPad's screen.

That VU meter is an interesting feature. Rogers forgoes conventional power specifications (eg, by watts into 8 ohms) to specify the 65V-1's power output in an unusual way "THD less than 0.5% at 1 Watt, less than 3% at 10 Watt output, 25 Watts peak."

618rog.app.jpg

In the 65V-1's manual, Rogers emphasizes the importance of this iPad VU meter, which samples the power output of both channels, then displays the continuous average power. (It is calibrated in watts, from 0 to 25.) They advise the user to study its readings and learn to recognize the sound of amplifier clipping, beginning by "increasing the gain control until saturation is heard in the speakers. The first indication of this distortion is powerful low frequencies overpowering higher frequencies. Note the relative indication of this point on the meter and operate the amplifier approximately 20% below this level." I no longer own an iPad, but I easily accomplished this task without the meter: I turned down the volume whenever I heard smearing, hardening, squeezing, or congestion.

Stereophile defines clipping as the power in watts at 1% THD+noise. By that measure, and judging by the 26 pages of Audio Precision test results included with every 65V-1, my review sample clipped at 3W. But speaking anecdotally, I'd call it a 10Wpc Ultralinear amp and a 3Wpc triode amp—the user selects between these two modes of operation—that handles loud transients pretty well. In Ultralinear mode, the screen grid of a tetrode or pentode power tube is connected to a tap on the primary windings of the amp's output transformer—and so a portion of the signal that appears on the tube's plate also appears on that screen grid, providing a type of negative feedback. (In pure pentode operation, which the Rogers amp does not offer, there is DC voltage on the screen grid but no signal.) In the triode mode offered by the 65V-1 and some other contemporary amps that use pentode tubes, the screen grid is connected directly to the plate, so there is no feedback effect.

Description
The 65V-1 measures 17" wide by 7.5" high by 12" deep and weighs 24 lbs. It's available with a choice of Mullard EL34 or Gold Lion KT88 tubes. Rogers included sets of both tube types with the review sample, and I tried both. Each unit is burned in for 100 hours before shipping, and comes with a transferable lifetime warranty.

To the right of the front panel is a ¼" headphone jack. Roger Gibboni told me via e-mail that the 65V-1's headphone gain is identical to the speaker gain: 26dB. The 65V-1's input impedance is 100k ohms. According to Gibboni, "Because the 65V-1 is single-ended, it has a slightly higher output impedance: 9 ohms at 2kHz and 8.5 ohms at 10kHz, which yields a damping factor of approximately 1."

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After attaching the Bluetooth antenna, power cord, speaker cables, and the interconnects from line-level sources to their respective connectors, flip up the Power toggle at far left on the front panel. Observe the red light at the toggle's tip. Wait 30 seconds, then flip up the Standby toggle to its immediate right. The 65V-1's front-panel controls are a snap to use. Spring-loaded toggles allow the amplifier to be switched between Standby and Operate, between triode and Ultralinear modes, between headphone and speaker outputs, and to select one of the four line-level inputs—three on the rear panel and one on the front panel. Both these switches and the amplifier's front-panel display are duplicated on the iPad app, which is the 65V-1's only form of remote control, and will be found essential by the visually impaired. In my bunker listening room, the amplifier's tiny (2.75" by 1.625"), violet-and-yellow display functioned mainly as a nightlight—it's almost impossible to read, even close up.

But that was okay.

Listening with Falcon Acoustics LS3/5as
I asked my Facebook friends: "What are the virtues and liabilities of single-ended tube amps?" Their Timeline replies rang true to my own experience: wholeness and continuity; a lit-from-within quality; they "breathe" naturally; hyper-three-dimensional; fully developed harmonics; organic, ear-friendly, coherent, stimulating, musically involving; they produce the finest nuances, incomparable midrange texture, amazing microdynamics, and eerie, preternatural tonality; an intimacy with music like no other; the intentions in the music are more discernible.

One friend wrote, "Virtues: inconvenient, antisocial, unconventional. Liabilities: inconvenient, antisocial, unconventional."

Along with weak bass, the most universally cited liability of single-ended amps was the difficulty of finding loudspeakers sensitive enough to match their low power outputs. Therefore, I thought I'd begin my study of the Rogers 65V-1 by connecting it to a revealing but low-sensitivity (83dB/2.83V/m), two-way, acoustic-suspension loudspeaker, albeit one with a tube-friendly high impedance (15 ohms).

A lifetime of owning Dynaco Stereo 70 amplifiers has created a storehouse of good feelings about EL34 tubes connected in Ultralinear driving various versions of the BBC's classic minimonitor design, the LS3/5a. So I had no choice but to connect the EL34-equipped 65V-1 to Falcon Acoustics' LS3/5a variant, which I reviewed in the August 2015 issue. I played a variety of roots, reggae, and British ska, and right away remembered: I've never experienced an EL34 amp I didn't like.

In my small room, the insensitive Falcons made some big, enjoyable sounds—but only at low volumes. With "Carbine," the final track of Black Uhuru's Red (LP, Mango MLPS 9625A), obvious dynamic compression set in at distinctly un-reggae-like levels (82dB/2m average). Triode mode was too low-powered to be usable.

All was not lost. At lower average volumes of around 76dB/2m, Cheng Gong-liang's Guqin (CD, Wind Music TCD 1027), "A UNESCO Masterpiece of the Oral and Intangible Heritage of Humanity" engineered by Kavichandran Alexander, of Water Lily Acoustics, was a sublime experience. The guqin, a 3000-year-old Chinese instrument similar to a zither, generates a complex palette of saturated tones that permit a range of expression that may exceed that of the Western violin. Long known as the "ancient qin," the guqin was the instrument of choice for Chinese poet-scholars. Through the Rogers-Falcon duo, this spectacularly beautiful recording showcased guqin master Cheng Gong-liang's Taoist spirit and creative fingerings. The sounds entering my chamber were exceedingly rich and exceptionally tactile. They reminded me for a moment of Jet Li's martial-arts sword fight in the Chess Courtyard, in the film Hero: Cheng Gong-liang's notes felt like the quintessence of pure, pulsing, fluxing energy. The Falcon-Rogers pairing's reproductions of this music were small and precise—it couldn't deliver realistic sound-pressure levels—but the transients of the guqin's plucked strings and the supersaturated colors of its harmonics were mesmerizing pleasures.

Listening with DeVore Fidelity Orangutan O/93s
With triode-connected EL34s, the Rogers 65V-1 played the DeVore Fidelity Orangutan O/93s (10 ohms, 93dB/W/m) loudly and dynamically enough to provide genuinely satisfying sound.

COMPANY INFO
Rogers High Fidelity
28 Church Street
Warwick, NY 10990
(845) 987-7744
ARTICLE CONTENTS

COMMENTS
tonykaz's picture

... for a Story!

HR does the bestist "Click-Bait" in the Audiophile Business.

I'll tell ya who that might be: Steve G visiting the Bunker delivering an On-Site Vlog Report. That geeky guy with all those Pass Apleflyers stacked up on his Altar to Gear Collecting. The very same guy that pointed me to Shit Asgard Amplification ( back in 2011, along with his side-man Tyll ) , this Guy has more Integrity than nearly anyone in NY,NY for gods sake. On top of it all he's got a way-cool shirt collection. Hmm.

This tiny Amp Review is one of the best Reads of the Year, so far.

Steve G & HR seemed to have survived the big Buy-out, phew, I was getting worried.

I'm still keeping my fingers crossed.

Please suggest that Steve spend some of his Mountainous Patereon Money on a Canon 6D & Vlog Lense system. The lads at B&H are waiting for him to walk thru their doors. Steve G can become the Casey Neistat of the Audio World!

Tony in Michigan

ps. I once owned a Nisson Pulsar 5 door Hatchback with 60 horsepower. It was that fastest little get around car I ever owned, it had to be driven intelligently but it delivered exceptional performance. QRP is a thinking man's effective tool.

ps. My Vote for Quote of the Year: "never heard an EL84 amp I didn't like"

ps. Mr. JohnnyThunder corrected me and my quoting of the quote. it's EL34 not EL84! Thanks Mr.Thunder

johnnythunder's picture

which is fab especially as I agree. It's the EL 34 tube that he is talking about the EL 84. EL 84s are good but EL 34s are magical.

tonykaz's picture

Right you are !!

I was in too much of a rush, trying to push out that Comment in between two scheduled things.

Plus, I wanted to be the FIRST one to respond, resulting in another proof for the Life Rule : "More haste, less speed" .

Thanks for writing and making the correction,

You da Man!!

Tony in Michigan

ps. EL34s even have a nicer smell. ( if anyone's in to that sort of thing, like I am )

Jason P Jackson's picture

I agree. It was this review that convinced me enough to get a yearly subs'. Mags like this one have their fair share of waffle. Nevertheless, good with the bad. And I've been known for my own occasional waffle.

mrkaic's picture

"Now I'm reporting on another class-A, single-ended amplifier, this one really low-powered. The 65V-1 integrated amplifier ($4000) uses EL34 or KT88 pentode tubes—at the time of purchase, the user specifies his or her preference—and is made by mainstream manufacturer Rogers High Fidelity, in Warwick, New York."

KT88 are TETRODES. KT stands for "kinkless tetrode". What an elementary mistake!!

Herb Reichert's picture

are Genalex and manufactured by New Sensor:

https://www.newsensor.com/pdf/genalex/kt88-genalex.pdf

they have five elements

mrkaic's picture

...the Genalex KT88 is just like any other KT88. It has the plate, the control grid, the screen grid, the cathode, and a pair of beam forming plates that are both connected to the cathode. That seems like five elements (counting the beam plate pair as one element) but only four different active electrodes exist in this type of tube, because the beam forming plates are connected to the cathode inside the tube. You can see that in the link you provided.

Now, a pentode has the plate and the cathode. It also has three grids: control, screen and suppression. Each of these elements has an active electrode, hence pentode — five active electrodes.

See this, for example https://drtube.com/datasheets/el34-sed2002.pdf

So, Genalex can call their KT88 whatever they want, but according to their own scheme, their KT88 has four active electrodes. The nomenclature depends on the number of active electrodes— Hence KT88 is a tetrode.

jmsent's picture

the original MO Valve Genalex datasheet calls the KT88 a beam tetrode. The New Sensor Genalex datasheet calls the same tube a beam pentode. The RCA datasheet calls it a "beam power tube". Seems like a grey area.

Herb Reichert's picture

If memory serves me, MO Valve invented the KT88 and it is as they say: a beam tetrode. But at that time, Phillips owned the patent for the power pentode and therefore all companies not associated with Phillips or unwilling to pay the license fee were forced to make “beam tetrodes” wherein instead of grid 3, the suppressor grid, a beam tetrode uses the concentration of the ion stream to do the same job. I call them all “beam tubes” as that is their common distinction.

I did however, as a proper fact-checking journalist, have to call the Rogers’ KT88s what their manufacturer calls them – pentodes. (Why does New Sensor call them beam pentodes? Don’t know. Maybe the Phillips patent is still in effect?)

But these are just words. To me, beam tubes have a unique sound character of their own, which, depending on the materials used in their construction, can range from turbocharged noisy harsh to beautifully lucid and hyper-detailed – like the original MO Valve KT88 beam tetrode.

Sorry for the confusion

herb

mrkaic's picture

You put a lot of effort into fact checking, that is quite amazing. Many thanks.

hifiluver's picture

Regarding Fig 2. Does this mean this amp will sound like it has a dip around the human voice with a shrill sound as the frequency goes up? My 15 year old Yamaha surround amp is a Ferrari compared to this Ford Model T.

johnnythunder's picture

would be able to discern the difference in sound quality between the Rogers amp and your "15 year old Yamaha surround amp." Obviously, I wouldn't use the Rogers amp for a home theatre system playing a Michael Bay film but that's another story entirely.

dce22's picture

It's 4000 bucks garbage for that kind of money you can buy one of the best if not the best tube amp in the world

Music Reference RM-200

https://www.stereophile.com/content/music-reference-rm-200-mkii-power-am...

ironically designed by the other Roger, Rogers needs to step up it's game if it wants to compete with Music Reference.

mrkaic's picture

Or one could buy a Quad VA One, also a superb amplifier.

ok's picture

..a tube guy after all.

mrkaic's picture

I enjoy my little VA One tremendously.

ok's picture

..as I always suspected!

johnnythunder's picture

for a $4k expenditure. Or that it even looks good (it doesn't in my opinion.) I have no doubt that the Music Reference is a fine sounding amp (it looks great too.) My comment was for the equally glib comparison of the Rogers vs. a 15 yr. old Yamaha surround sound amp.

mrkaic's picture

...probably look better than anything out there. If you can't measure gear, you might be very happy with them -- as was I, for a time. My LM-216 sounded good and looked marvelous. But after I had measured it, I had to return it. I suspect that the thing must have had bad output transformers, since the response to square wave input showed intolerable ringing. So, there you go. Still miss the looks of that amp, but one has to be ruthless with gear that measures poorly. Looks are not everything, ears can be deceived easily, but oscilloscopes don't lie (if you know what you are doing). Incidentally, Quad VA One has great looks and measures well.

johnnythunder's picture

by a group that has obviously done their vintage audio equipment homework. I actually am not looking for a new amp. I have a Lector ZXT-60 hybrid integrated. The design is simple and elegant and has a high wife acceptance factor. She did not want exposed valves. An upgrade for me would probably be for something in the French Audiomat line. Class A. EL 34s. Synergistic match with my French JMR speakers.

woodford's picture

thanks for the great review- it's wonderful reading.

i wonder how the amp might sound w/ KT77s? in my, admittedly limited, experience KT77s provide the saturation of EL34s you speak of, with the punch and dynamics of KT88s. i use them in my Icon Audio ST40 in Triode mode, and they sound fabulous.

btw, the Icon is an amp stereophile should review.

John Atkinson's picture
woodford wrote:
i wonder how the amp might sound w/ KT77s? in my, admittedly limited, experience KT77s provide the saturation of EL34s you speak of, with the punch and dynamics of KT88s.

Years ago I replaced the EL34S in my Michaelson & Austin TVA-10 with KT77s that I had purchased from the M-O Valve Company. My experience was similar to yours.

woodford wrote:
i use them in my Icon Audio ST40 in Triode mode, and they sound fabulous. btw, the Icon is an amp stereophile should review.

As Icon currently has just 2 retailers in the US, the brand doesn't qualify for a full review. (We require a brand be available from 5 or more US dealers.)

John Atkinson
Editor, Stereophile

woodford's picture

I wonder whether the 5 dealer policy should be revisited for an age in which many consumers do their shopping online. assuming of course the online dealer (in this case, Music Direct) is reputable, and services all or most of the country.

in any event, it's a great amp in my opinion, easily competitive with similar amps from Line Magnetic, Prima Luna, et al.

dalethorn's picture

To me, online buying raises the issue of returned merchandise. I wouldn't expect most returned items to be repackaged and sold as new, but premium amps aren't like clothing and other easily exchanged or refunded goods sold online, and I wouldn't expect such dealers to take a beating having to sell the returned items as used.

Anton's picture

Seems like an online product, to me, as well.

Good return policy, factory warranted online dealer...I'd give it thumbs up!

woodford's picture

John- i wonder whether there's really a material difference between domestic manufacturers like Zu and Schiit that sell direct, and imports like Icon which sell primarily through a single online outlet. Stereophile has reviewed products from both of the former.

tonykaz's picture

I'd have no trouble accepting any of their stuff which sells used on Ebay for around 80% + for a "Previously Owned" current Model.

Besides...

... used eBay prices are a dam good way to evaluate Gear's ability to please "Real" owners.

Tony in Michigan

ps. most Loudspeakers don't do well in the Used Market but those cute little LS3/5s still get mucho dinero ( x5 original Retail Prices )

rt66indierock's picture

I read your Rogers view just before I left for T.H.E. Show. When I walked into Room 312 and saw the AGD Vivance Monoblock I thought of your first paragraph. Give them Class D in a Vacuum tube and audiophiles will lap it up.

johnnythunder's picture

I'd prefer Rogers hold down the Class A tube fort the good of all audiophiles (that like low power and the inherent restrictions/sonic benefits of Class A amp that is.) If I could own one Rogers product and had the space for a larger tube phono stage it would be the Rogers PA-1A.

rt66indierock's picture

This is class D in the tube. Looks like a tube mono amp. Rogue is a hybrid. This isn't.

I listened for a long time to the amp at T.H.E. Show because of the Allen Sides speakers. Because who am I kidding there are things I like and his Eureka speakers have them. Very surprising for a speaker with a port. The Monterey's in a bad room sounded pretty good.

hifiluver's picture

i have a looping video of an open fire place on my flat panel display but it doesn’t keep me warm in winter.

Tubes are funny honeys. They have a freq. response which can be replicated on a solid state amp coupled to a $50 dollar second hand graphic equaliser. The harmonic distortion can be introduced with shareware software. Pity I can’t replicate the lack of clean transparent power with little control over those big woofers.

13DoW's picture

There is very little say that is positive about the measured performance "But props to Roger Gibboni for the useful iPad app" :)

billyb's picture

Mr. Atkinson,
Would it be fair to say this review includes one of the worst test bench results for an amplifier in Stereophile history?
Obviously, with a square wave and distortion like that, there is much to criticize.

We all know test results only tell part of the story from a subjective listening perspective, but when you receive such an outlier on the bench wouldn’t you be doing a service to the readers to expound in a leeetle more detail than the mic drop above implies?

lousyreeds1's picture

Herb, I would love to know how Decware's low-watt and VERY affordable SET amps perform in your system up against the likes of Pass, Line Magnetic, Rogers, etc. Seems like with your small space and high-sensitivity speaker collection, Decware could be a good fit.

Thanks for the great review.

dalethorn's picture

I'd add a vote for Decware as well. They put a lot of emphasis on keeping the signal path as clean and uncluttered as possible, even if there's a risk of blowing a component because they don't include as much protection as their competitors.

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