It’s easy to build a tube amplifier, relatively speaking.  I did it in high school electronics class.  It played music and buzzed like hell, but it sounded fairly good compared to the JVC receiver my parents owned.  There was just something unmistakably yummy about the way acoustic instruments and vocals sounded through my old-school AR speakers that hooked me on tubes forever.

It’s not so easy to build a great tube amplifier, though.  I’ve got no skills in that arena.  Many of today’s tube-amplifier manufacturers follow one of two paths: rebuild a classic from the vintage era (1940s and 1950s) with good success, or embrace more modern technology and tubes to produce an amplifier with the best characteristics of legacy and current thinking.  Put the EHF-200 MK2 from Rogers High Fidelity squarely in the latter camp.

This amplifier takes full advantage of company principle Roger Gibboni’s years of engineering expertise in the world of communications and radar technologies.  The amp combines solid circuit design and meticulous point-to-point wiring with high-quality current parts, like a massive 1100VA toroidal power transformer and beefy output transformers, to create an instant classic.  Gibboni says on the Rogers website that one of the company’s goals was “to create an amplifier that your kids will fight over when you’re gone.”  And with a lifetime warranty, the EHF 200 MK2 should outlive you.

He has succeeded brilliantly, and if the beautiful casework doesn’t convince you, then remove the bottom cover and gaze at the workmanship.  It’s instantly obvious that this amplifier is built with a lot of TLC—and built to last more than one lifetime.  Only the highest-quality, tightest-tolerance parts lurk under the hood.  MSRP for the MK2 model, which includes preamplifier inputs and a variable-level output, is $14,000 even.  (The standard EHF-200 model does not have this flexibility and so it is priced slightly less at $11,500.)  The MK2 features three single-ended RCA inputs on the rear panel, along with another set on the front panel.

Spacey Indeed

The Radiohead classic “High and Dry” instantly reveals the spatial abilities of this amplifier.  Lead singer Thom Yorke is firmly anchored in the mix, with some strong guitar bits and a few layers of synthesizers perforating the mix in a highly obtuse but effective and three-dimensional way.

Springsteen’s “4th of July, Asbury Park (Sandy)” comes through my vintage Acoustat 2+2s with a fervor that I’ve never experienced since having the speakers expertly rebuilt.  There’s an unmistakable magic that has always existed between tubes and electrostatic panels that always seems to make the world stop for a while as you drink it in.  Thanks to the drive this amplifier possesses, triode mode rules the day, and so young Springsteen’s voice is buoyant between the 8-foot-tall panels.  And thanks to the subwoofer outputs, driving a pair of powered subs is a cakewalk—a valuable feature often overlooked on many integrated amps.

Major Style Points

The EHF-200 oozes style, from the deep red color of the chassis to the cool blue power meter on the front panel.  And, of course, glowing vacuum tubes are always a hit with music lovers and audiophiles alike.  The amp comes with a billet remote that is a piece of sculpture, and Rogers also includes a microfiber towel with the company on it logo to keep your amplifier free of fingerprints and scratches.

From the amp’s carbon fiber and rhodium speaker binding posts to the finely machined controls, it’s clear that the amount of thought that went into this product is indeed high.  Its built-in headphone amplifier works symbiotically with the usual suspects in my headphone arsenal, which includes Grado, Sennheiser and Audeze phones.  Each Rogers amplifier even comes with a handwritten note from the person who assembled it, telling you to enjoy your purchase—a nice personal touch.

It’s worth noting that there is a pair of RCA input jacks on the front panel, a reviewer’s dream if there ever was one!  No more fishing behind the equipment rack to find the remaining input.  Active audio hobbyists who switch and compare gear on a regular basis will really appreciate this feature.

Every aspect of the EHF-200 operates with extreme silence, from the subtle clicking of the volume attenuator to the switching back and forth between triode and ultralinear modes.  Some amplifiers we’ve auditioned clunk fairly dramatically when changing modes, requiring the amplifier to be turned off every time, but the EHF has no such problem.  You will immediately notice more gain in ultralinear mode, but this reviewer finds the extra sweetness of triode operation to be worth the small increase in gain required for full output.  My reference dCS Vivaldi has 6 volts of output, so this was no problem at all.

Major Performance, Too

Style without substance is meaningless—and when the pedal goes down, the EHF-200 MK2 fires up.  With a quartet of KT120 tubes, (two per channel), the EHF produces 117 watts per channel into 4 ohms in ultralinear mode and 80 per channel in triode mode; just flip a switch on the top panel to change modes.  The power tubes are all biased automatically, so there is no need to worry about adjustments or scouring the earth for matched quartets.  This should make the EHF as trouble free as a tube amplifier can get.

The applause in Cheap Trick’s “Day Tripper” hints at the EHF’s ability to reproduce a large soundstage.  This amplifier paints a musically accurate picture that still renders a hint of tubeyness.  The EHF’s overall tonality reminds me of the much more expensive Octave Jubilee monoblocks that we recently reviewed.  The EHF is not as warm as a Conrad-Johnson amplifier, but it’s not quite as reserved as my Audio Research REF 150.  And though the REF 150 has a bit more power (150 wpc versus 117 wpc), the EHF is a thousand bucks less for a full integrated.

Though the Acoustats have a sensitivity rating of only 82 dB per watt, the EHF has no trouble driving them to more than adequate levels, even in triode mode, which again is absolutely dreamy.  The rest of the speakers at my disposal are all considerably more efficient, so the EHF never runs out of steam, unless I play music so much louder than is reasonable and prudent.  And even then, it clips so gently that there is only a slight compression of the soundstage to warn you that you’ve gone too far—that is, if you aren’t paying attention to the little blue meter on the front panel.

Wendy Lewis’ lead vocal on the Bad Plus’ For All I Care is positively goose-bump inducing, especially her detached rendition of the Bee Gees classic “How Deep is Your Love.”  The EHF is a tonemeister, always straddling the line of perfection, never embellishing too much, yet it is always musical and engaging.  The subtle harmonics on both ends of the frequency spectrum from Charlie Hunter’s eight-string guitar on his Bing, Bing, Bing! album bounce around the room in a spectacular manner, with decay that seems to go on forever—another hallmark of a great tube amplifier.

I move the EHF to room one and pair it with the 90-dB-per-watt KEF Blades, and it continues to dazzle with it’s ability to generate serious low-end grunt.  Cranking the latest effort from Kanye West illustrates how well this amplifier not only generates serious LF information, but how much control it also exhibits.  Keeping the party rolling with Genghis Tron’s Board Up the House disc adds layer after layer of highly distorted guitars to the driving beats, neither of which cause any difficulty for the EHF.

Tonality is beyond reproach, as hours of listening to audiophile classics will verify.  Those living on a steady diet of female vocalists and plucky acoustic guitar records will surely wet themselves over the EHF’s presentation.  And those who like to rock (I salute you) will dig the dynamics that the EHF brings to the table.  Its robust power supply allows it to play louder than its size and specs would suggest.  Cranking up the live version of the Tubes’ “I Was a Punk Before You” is exhilarating, as is Jeff Beck’s album, Live at Ronnie Scott’s.  There’s just something about tube amplification that lends itself to raucous rock—and the EHF delivers in spades.

Tube Choices

Some will argue about the sonics of the KT120; yet, after living with this tube in a number of other amplifiers, I am in the love it camp.  The EHF works well with the KT120, offering more than enough delicacy to make the most devout tubeophile happy.  It offers better dynamic contrast and impact than the KT88/6550 is able to muster.  And we’re only talking four power tubes here, so when it is time to re-tube, it won’t cost a fortune.

With the 12AX7 in good supply, the sky is the limit for those feeling the need to tube roll.  The EF86 tube is NOS with no major substitutions, so if your taste doesn’t go to the exotic, re-tubing the EHF will be painless.  After trying a handful of different 12AX7s at my disposal, sticking with the stock JJs proved a great place to hang my hat.  Stick with the stock tubes and enjoy, I say.  And stick with the packaged Quiet Cable power cord too – this would easily set you back a thousand bucks, for something equivalent from one of the majors.  I tried my favorites from Shunyata, Cardas and Audience with no improvement whatsoever, so use the one in the box with confidence.

An Elegant Solution

With so many people trying to simplify their lives, the Rogers EHF-200 MK2 is a refreshing solution.  Of course, $14K isn’t exactly play money, but the sound quality delivered by this amp easily equals or betters most amp/preamp combinations that are similarly priced.  And remember, going with a combo solution will require at least one premium interconnect and a pair of power cords, so if you’re playing at this level, plan on dropping at least a few extra thousand on wire just to be on par.

With the EHF-200 MK2, Rogers offers a world-class solution in one box.  Add your favorite digital and analog sources (should you be so inclined) and you’ve got a super system that fits on a single rack.

This is an amplifier we thoroughly enjoy.  If you’ve been looking for something a bit out of the ordinary and a bit more bespoke that offers the full-on tube experience, look no further.   The EHF-200 MK2 is fantastic.

Rogers EHF-200 MK2 Integrated Amplifier

MSRP:  $14,000

rogershighfidelity.com

Peripherals

Analog Source	SME 10 turntable    Sumiko Palo Santos cartridge    Aesthetix Rhea phonostage
Digital Source	dCS Vivaldi stack    Sooloos Control 15
Speakers	Acoustat 2+2    KEF Blades    Dynaudio Confidence C1 II
Cable	Cardas Clear Light
Power	Running Springs Dmitri

Early class D amplifiers resemble the first efforts at CD players; a great idea that wasn’t fully realized on the first iteration or two. If you’ve been around long enough to remember just how bad those first CD players sounded, you’ll probably agree that the first class D amplifiers offered up the same aural aesthetic, sounding two dimensional, somewhat shrill on the top end and fatiguing after a short period of time.

In the last year or so, class D has improved dramatically and recent efforts by Devialet (a variation on the class D concept), Audio Research and Bel Canto reveal that these amplifiers can hold their own with their more current hungry brothers.

Add Channel Islands to that list, matter of fact, put them right at the top. The latest D-500 MKII monoblocks you see here are incredibly capable. Unlike other designs the CI amplifiers utilize a custom, full-bridge module that is not available to the DIY community along with some of their own circuitry. CI owner Dusty Vawter told me that they only use the UcD modulator and Class D output section of the module. The rest is customized in house. “You need to do some serious R&D to get great sound, you can’t just stick an ICE module in a box.”

Channel Islands has built some massive power supplies to go along with these amplifiers. While small on the outside, they weigh almost 30 pounds each. Popping the top reveals large capacitor banks and heavy wiring – these amps are built to rock. However a little bit of patience is required; the D500 MKIIs sound pretty stiff out of the box, but once powered up and played for about 2-3 days, the congestion clears to a bold, dynamic sound. Vawter mentioned that the modules have some power constantly applied when in standby mode, so they only take about 10 minutes to sound their best once the initial run in has been completed. Considering that these amplifiers only draw about 13 watts of power each, I suggest leaving them on all the time.

Speaker Compatibility

Past experience with Class D amplifiers reveals they are often sensitive to speaker matching, just like a vacuum tube amplifier- some combinations can be fantastic, while others can be awful, so an audition is definitely required. We made it a point to audition the D-500 MKIIs with a wide range of speakers: The Verity Rienzis, MartinLogan Aerius and ElectroMotion, the Magnepan 1.6, 1.7 and 3.7s the new Dali P5, Harbeth P3ESRs, B&Ws 805 and 802 Diamond and of course, my reference GamuT S9s.

This comprises a fairly wide range of loads, some easy to drive, others not as much. The D-500 MKIIs turned in an excellent performance in with everything on the list except for the B&W Diamonds. Wanting to verify whether this was anomalous behavior with my speakers or something else in my reference system, installing the D500 MKIIs in another system featuring 800 Diamonds exhibited the same rolloff in the HF region, compared to all the other amplifiers at my disposal. I would suggest the owners of B&W’s Diamond series to get a thorough demo first and CI agrees – they offer a 30 day money back guarantee – less a 10% restock fee and return shipping. A small price to pay to assure system synergy.

It’s also worth mentioning that the D-500 MKIIs worked well with a wider range of speakers than any other Class D amplifier I’ve yet sampled. And they are an exceptional match with the Magnepans, which are typically power hungry. If you are considering a pair of Maggies, the CI monoblocks would be at the top of my list.

Preamplifier Compatibility

The D500 MKIIs are neutral tonally, neither adding warmth to the sound, nor forward sounding in a way that could be construed as a thin presentation. However, system synergy and compatibility is always an issue – in the view of this writer perhaps one of the most important, yet most often disregarded elements of system setup.

Marvelous results were achieved with all four of the preamplifiers on hand. (Croft 25, McIntosh C500, Burmester 011 and the Audio Research REF 5) All but the Croft were balanced preamplifiers and connected thusly. While the arguments continue to go back and forth about the value of balanced versus single ended design, I preferred the D500 MKII’s in balanced mode more – the presentation appeared a bit quieter overall. However, if you have a single ended (RCA) preamplifier, don’t shy away from these amps, you will not be disappointed.

Preferring the combination of a tube preamplifier with a solid state power amplifier to cheat the equation, if you will – getting the grip and slam of solid state with the added warmth of tubes thrown in for good measure worked well here. Neutrality is a two edged sword; some want to hear everything on a record “warts and all,” while others want hyper detail, with yet others liking a certain amount of tonal richness to the sound (that can either be described as warm, romantic or even distorted).

Biases exposed, a little bit of tonal warmth still gets my vote, as long as it doesn’t affect the pace of the music – a tough order, but it can be done. The perfect combination ended up being with the McIntosh C500 control center, a two box preamplifier that incorporates an excellent MM and MC phono stage built in, with enough inputs for everything you can imagine. Vawter encouraged me to take this direction, “We have a lot of customers that really enjoy our amps with a tube preamp.” The C500 used as a reference component at TONEAudio is hot rodded ever so slightly with a full compliment of EAT 12AX7 tubes that retains the tonal balance of this preamplifier while offering more dynamic range and a lower noise floor.

Because the D500 MK IIs possess very high gain, (32db or they can be supplied as a higher gain model featuring 38db of gain), most preamplifiers should present no problem and these amplifiers should lend themselves well to a passive preamplifier as well. When using the CI amplifiers with the ARC REF 5, the level never went past 15 on the fluorescent display to achieve maximum volume, which is very low. Even vintage preamplifiers with minimal output will have no problem driving the D500 MKIIs to maximum output.

Further Listening

The neutrality that these amplifiers exhibit makes them a great building block because they will not add to the character of other components in your system, making it easier to lock in speakers (undoubtedly the toughest component to interface with your room) and amplifier while tuning to taste, if necessary, elsewhere. Think of your amplifier and speakers as the rhythm section in a band – that essential foundation, that everything else builds upon.

Trixie Whitley’s lead vocal just leapt out of the GamuT’s on the first track, “Love Lives” from Black Dub’s self titled album, with Daniel Lanois’ backing vocals floating from left to right across the soundstage, somewhat diminished in the distance. An abrupt switch to a few trippier selections from Jean-Michel Jarre further confirmed the three-dimensionality delivered by the D500 MKIIs. Equinoxe never sounded better, and Zoolook offered up stirring bass lines.

Following this quest for bass a little further, Ursula 1000s disc, Mystics proved that the D500 MKIIs could not only deliver a large soundfield, but they could deliver deep bass with power and control. Pushing the G9’s to rave music was effortless and even at deafening volume (It felt like being back at the MICS festival in Monaco, minus the dancing girls) these amplifiers kept a lock on the pace, offering up wall shaking beats with no shrinkage of soundstage in either dimension. And of course, all the Yello tracks rattled the room.

This grand soundfield increased as I switched to vinyl – after a few of my favorite LP’s I forgot that I was listening to the tiny boxes on top of the $60,000 pair of Bumester 911 power amplifiers. Again, Vawter encouraged me to compare the D500 MKIIs to the best amplifiers I could get my hands on and they proved formidable. When listening through the GamuT S9s there was still one hurdle between the Burmester, ARC and Pass Labs amplifiers at my disposal in terms of removing the last bit of grain, or palpability, but I can’t remember ever hearing a pair of $5,000 amplifiers sounding anywhere near this good. It was only when I returned to the big bucks amps that I noticed a difference.

Making the power hungry Magnepan 1.7’s part of the equation was equally splendid. One of the biggest dilemmas with the Magnepan speakers is that while they are highly revealing for an inexpensive speaker, they require a lot of power to really light up the listening room. The D500 MKIIs took control of the Magnepans as well as some of the world’s best amplifiers have- I can’t think of an amplifier I would suggest more highly for someone looking to build a high performance system around the 1.7’s (or the 3.7’s for that matter) at a reasonable cost.

The absence of a sound

The Channel Islands D500 MKII amplifiers sounded great and made no missteps while in our care. We will be adding them to our reference fleet of amplifiers, so you will be hearing more about them in the months to come. I feel compelled to give these amplifiers one of our Exceptional Value Awards for 2011 as well – they represent tremendous performance and build quality. A well thought out product in every way.

The Channel Islands D500 MKII monoblocks
$5,000/pair

www.ciaudio.com

Peripherals

Preamplifier McIntosh C500

Analog Source AVID Acutus Reference SP w/SME V and Koetsu Usushi Blue

Phono Stage ARC REF Phono 2

Speakers Gamut S9

Power Running Springs Maxim and Dmitri power line conditioners