Conrad-Johnson ART 150 Power Amplifier

For their 40th anniversary, Conrad-Johnson started shipping their new limited-edition, tube-based flagships, the ART150 stereo amp and ART300 monoblocks.

Over time we have had the opportunity to review C-J’s current lineup of amplifiers including MF2550 and MS2275 solid-state designs, and the Classic 62 tube amp. Each one has its strengths, but there is not a slacker among the bunch. The ART150, however, takes things to another level of detail and soundstaging with a very natural, and organic sound. It indeed won our team over, earning the TONEAudio 2017 Product of the Year in the amplifier category.

Using a tube compliment of four new-production Tung-Sol KT150 tubes and three 6922s, the ART150 produces 150 watts per channel, plenty of power to let most speakers sing. The ART150 shares a visual lineage with C-J designs past, what’s under the hood is all new. Every detail in this design was scrutinized by the C-J team, including proprietary transformers and CJD Teflon capacitors alongside carefully-chosen foil resistors and wire for the delicate signal path.

With such attention to detail and a legacy of stellar products, Conrad-Johnson has another big winner with the latest ART amplifiers. Our full review is coming soon, so you will be able to get all the details.

McIntosh Announces MA252 Integrated…

Today McIntosh announced the release of their new MC252 integrated amplifier, to a wide range of polarizing comments around the world.

With an MSRP of $3,500, this is a pretty kick ass little package. The approximately 12 x 18 inch footprint makes it about the size of a PrimaLuna amplifier, so it’s not going to take up a ton of space wherever you end up placing it, and at only 28 pounds, nearly anyone can lift it into place – pretty cool for McIntosh.

A hybrid design, the MA252 uses four tubes in the input/driver segments and a solid state output stage, delivering 100 watts per channel into 8 ohms and 160 per channel into 4 ohms, so you’ll have enough juice to drive most any speakers. A headphone amplifier is included and an MM phono section as well.

You can see by the rear view, that there is one balanced XLR input, two unbalanced RCA inputs and the phono, along with a single, mono output for a powered subwoofer. This should make it easy to make the MA252 the anchor for a great compact system.

Visually, the 252 pays homage to past classic McIntosh tube amplifiers, adding the current aesthetic of LED’s underneath the tubes and a digital display to indicate function and volume level. You’ll love it or hate it, but it’s pure Mac, and built on the same assembly line in Binghamton, New York with all current day McIntosh components.

We look forward to a full review as soon as samples start shipping!

Please click here for more tech bits!

The Coincident Dynamo SE 34Mk. II

There is a coherence to the single ended triode design that is tough to ignore. Passing the signal through a single triode in the output stage has a grain free purity that will have you converted in no time at all.

Critics around the world raved about the original version of this amplifier (Priced at $1,295) and though I haven’t had any personal time with the original, every other Coincident product I’ve auditioned or owned has been a top of class product. The current Mk. II version is now $1,495, and has had nearly every component beefed up. Bigger transformers, bigger capacitors, more power supply capacity, etc., etc.

And the chassis is beautiful. As Coincident’s owner Israel Blume comments, “While far more costly than chromed steel, stainless steel is non-magnetic, eliminating hysteresis distortion and the mirror finish is permanent – unlike chrome, which is prone to pitting and eventual peeling.” This is not only a component you want to put front and center – proudly, it’s a component you will probably hand down to a family member.

Heading straight for the female vocal tracks, Anja Garbarek’s Smiling and Waving proves a revelation, with Ms. Garbarek’s voice materializing between the two Coincident Dynamite speakers that have been sent along to review. My other favorites, Ella Fitzgerald, Shelby Lynne and Anne Bisson all seem to just walk out from inside the speakers in such an effortless, grain free, natural way. Even though they have a sensitivity rating of 90db/1-watt, the Mk. II drives them with authority.

It feels more like a 20 or 30 wpc amplifier, and my old Dynaco Stereo 70 (30wpc on a good day) runs out of steam quicker than this 8-watt per channel wonder. It’s amazing what solid vacuum designs coupled with modern manufacturing can produce.

Why the EL-34?

The Dynamo SE34 Mk. II takes a slightly different approach to the SET thing, using a single EL34 pentode, configured as a triode, with a single EL34 per channel in the output stage, driven by a 6SL7 tube. These days, a good supply of EL34s are available as new stock tubes and the Mk. 3 sounds great as it is right out of the box.

When asked about this seemingly off the beaten path choice, when so many SET amplifiers are built around a 300B or 2A3, he replies, “the EL-34 is widely available, inexpensive, and has exceptionally low distortion when used in single-ended triode mode. Most importantly, this tube has wide frequency response, offering a highly transparent and neutral tonality.”

The proof is in the listening. Removing my $20,000 Nagra 300B amplifier from the system and replacing it with the Mk.II doesn’t reveal a delta of $19,000. Much as I love the Swiss brand, the truth is in the listening. And with a couple of super high efficiency speakers in the system, I prefer the Coincident amplifier.

Extra credit

While this is essentially a budget amplifier from a price standpoint (though not in performance) it may not make sense to someone to invest in another $500 or more in NOS tubes. The Mk. 3s small tube compliment (2 – EL34s, 2-6SN7s and a 5AR4) makes this amplifier a tube rollers delight. Seeing I just happened to have some great Siemens NOS EL34s hanging around, as well as the other two, it was worth investigating. To make this clear, the Mk.II sounds fantastic out of the box and like some tube gear I’ve heard, it does not need a set of vintage tubes to make it sing. However, thanks to the Mk. II being gentle on tubes to begin with, investing in a few NOS tubes can be fun and rewarding. Think of it as replacing the Pilot Super Sports on your car with Cup 2s, or for those of you that aren’t auto enthusiasts, the icing on the cake.

Ultimate simplicity

Music lovers just playing vinyl or digital exclusively, can use the Mk.II as your sole component, as it has a single pair of RCA, line level inputs – no preamplifier is required. Most of the listening tests conducted running the dCS Rossini DAC/Clock straight into the Mk. IIs line level input went great connected directly. When switching between multiple source components, the Pass XS Pre was used. That these are 40 and 65 thousand dollar components speaks volumes as to how much music this diminutive box reveals.

Thanks to auto bias, the output tubes won’t need much attention. Combining this with the soft start function of the tube rectifier, tube life should be excellent, as it is with the rest of the Coincident product line. All wiring is point to point, so even if something should ever fail, repairs will be easy to troubleshoot and easy to diagnose, just as the best vintage components from Marantz and McIntosh are.

Better than the numbers

Have you ever met one of those scrappy little dogs that thinks he’s a big dog? That’s the Dynamo; this amplifier has a huge heart. Though a single ended design, this amplifier is affected far less by speaker and crossover loading than any other SET I’ve lived with. Your listening habits will dictate speaker choice, but I suggest keeping to 90db/1 watt speakers or better. Coincident’s own Dynamite speakers proves tons of fun, as do the equally efficient Vandersteen 1s. Thanks to that beefy power supply and the headroom it affords, Blume tells me that he has owners with 86db/1 watt speakers report they are more than satisfied with the Mk. II’s output.

As mentioned earlier, this amplifier has a more robust power supply than its predecessor and offers amazing grip in the bass region, something small SETs usually lack. Even when listening to heavy rock or EDM tracks, this amplifier offers up a solid musical foundation. Where some SET designs are notorious for loose, floppy, one-note bass, the Mk. II keeps a lock on things. I was pleasantly surprised at how loud I could play Led Zeppelin and Tool before the soundstage flattened out from being overdriven.

The magic is in the midrange and upper registers, and this amplifiers ability to reveal layer upon layer of musical texture is indeed sublime. Listening to the current remix of the Beatles’ Sargent Pepper, which for those not familiar is a more dynamic, forward mix than even the remastered discs from about six years ago is sheer joy. With so much more information at your disposal, it’s not only easier to hear all the individual instrument lines, the harmonies of the group are now more accessible as well. An equally pleasant rendition of the audiophile warhorse from The Fairfield Four, Standing in the Safety Zone is achieved with the Mk. II. Those four guys just seem to inhabit the listening space. If there was ever an excuse for the “less is more” attitude towards design, the Mk. II nails it.

Vintage fun

Making it a point to get a pair of Zu Druids in to experience what super-efficient speakers can do with 8 watts per channel, going back in time proves even more enjoyable. A recently acquired pair of mint, mid 70s Klipsch LaScalas mated to the Mk.II is some of the most fun I’ve ever had listening to music. Combined with the Simaudio NEO 260 CD player/DAC (purchased used in excellent shape from our pals at Echo Audio in Portland, Oregon) the entire system is about $3k.

Dynamics are definitely the fourth dimension in music, and listening to some of my favorite classic rock records with this kind of pure sock, is immersive to say the least. Whether jamming out to the alarm clocks on Dark Side of the Moon, or some Jimi Hendrix, the Mk. II paints a vivid, three-dimensional soundstage that is easy to swim around in. Hifi doesn’t get any more fun than this. Should you be a Klipsch lover looking for the perfect amplifier, this is an amazing choice and my personal favorite. I’ve never heard a pair of LaScalas sound better. I suspect the Mk. II would be equally great with Altec Voice of the Theater speakers as well. The only thing I didn’t get to try was a pair of single driver speakers. Maybe next time.


If you’ve got speakers that can live with 8 watts per channel, I can’t suggest a more enjoyable amplifier than the Coincident Dynamo Mk. II. It offers a degree of refinement that you’d expect from a tube amplifier with another zero on the end of the price tag. Along with being robustly built, the Mk. II is aesthetically pleasing to boot. Those with a huge room and average sensitivity speakers might consider a larger amplifier from Coincident, but if you can work within what the little Dynamo can deliver, it’s very impressive.

Considering that a decent, stand-alone headphone amplifier alone will set you back $1,500 these days, getting a power amplifier too makes the Mk. II a stone-cold bargain. Running through the gamut of headphones at our disposal, (Audeze, Grado, Koss, Pryma and OPPO) reveals the Mk. II has no difficulty driving any of them. Blume reveals that instead of an inexpensive op amp, the output of the amplifier drives the headphones directly, so that the output available is huge. This also gives the benefit of your favorite phones having the same sonic signature delivered to your speakers.

So, if this sounds like your idea of the perfect audio joy ride, give Mr. Blume a call and tell him we sent you. The Dynamo Mk. II is highly deserving of one of our Exceptional Value Awards for 2017, and if we gave out an “Extra Effort” award, it would win that too.

The Coincident Dynamo SE34 Mk.II amplifier



Analog Source            Grand Prix Audio Monaco 2.0 turntable/Tri-Planar/Lyra Etna

Phonostage                  Pass Labs XS Phono

Digital Source             dCS Rossini DAC and Clock

Speakers                      Coincident Dynamite, Vandersteen 1Ce, Zu Druid, Klipsch LaScala

Cable                           Cardas Iridium

Power                          Equi=Core 1800

The Audio Research GS 150 Power Amplifier

I probably should listen to more classical music at comfortable volume levels.

Back in 1990, when I finally got my hands on an Audio Research D-79 after wearing down a good friend to part with it, he called to inform me that I should “let it warm up slowly with some nice string quartet music.” No way. The first track played was Alice Cooper’s “Hey Stoopid,” and after a few minutes to warm up, I pushed those big meters all the way into the caution zone. Having grown up with polite little EL-34 tube amplifiers, this was a revelation. I had never heard a tube amplifier that had the drive of a big solid-state amplifier before. It was equally revelatory to my next door neighbor, who was pounding on my front door before the first chorus.

I have not grown up one bit 25 years later. At first listen, it seems like the Audio Research GS 150 that has just arrived for review has defective power output level meters.  UFO’s “Lights Out” is playing at much higher than normal conversation levels, but the needles aren’t budging. Volume indicator on the GSPre is set to 42 and we’re all thinking that at least a few watts per channel are being delivered to the Dynaudio Evidence Platinum speakers we use as a reference, but to no avail – still no movement. Raising the level to 60 finally makes for some meter movement, and the sound level is indeed rambunctious! Yet the GS150 can play much, much louder.

Going for broke, pushing the meters to swing past the 150-watt mark towards the caution level during Michael Schenker’s blistering solo, with no trace of distortion, convinces me this is indeed a very special amplifier. Call me nostalgic, but I haven’t had this much fun with an Audio Research power amplifier since the days of my D79. Whether you listen to chamber music or metal, the level of involvement that the GS150 brings to the table is precious.

ARC’s REF amplifiers are wonderful, and I’ve even owned a few of them over the years, but this new GS series of Audio Research components is unique in the sense that it blends a tiny bit of the vintage ARC sound with everything they’ve learned in 40 plus years of amplifier design. Add the super stylish Italian casework and this is the amplifier that’s going in my coffin.

Last year we bestowed an extremely complimentary review on the Audio Research GSPre, enjoying its combination of Italian style with a return to the glorious all-in-one preamplifiers of the past, featuring a full-function phono stage (and a headphone amplifier) all on one chassis. The matching GS 150 power amplifier is equally beautiful and equally capable. Perhaps even more.

A special sound, indeed

When it comes to splitting hairs, the GSPre renders music with slightly more body and slightly less resolution than the REF 5SE and REF Phono 2SE combination, albeit at a much lower price. (The REF 5SE/Phono 2SE pair will set you back close to $30k, the GSPre has a $15k price tag) The delta between the two isn’t so much less than different. Even though a BMW M4 will get you around the racetrack a little faster than a fully equipped 435i with sport suspension, the latter is a more reasonably priced car to live with every day if you can’t take advantage of its maximum performance on a regular basis. The same holds true for the GSPre.

However, the GS150 is a different animal indeed. Possessing a similar sonic signature to the GSPre, it offers all the detail and resolution that the REF power amplifiers are known for, yet that pinch of tubeyness is there and not in an overwhelming way to ever sound slow, rounded off or overly euphonic.

At $20k the GS150 is a step above the REF 150 in ARC’s product lineup and in a side-by-side comparison provides a different sound. Though the spec sheets look almost identical, these two amplifiers are different beasts indeed. They do share a fully balanced configuration, and like the REF amplifiers, the GS150 must be used with a balanced preamplifier; it will not work with a single-ended preamplifier and balanced adaptors, so take this into account before purchase.

Vivacious violins, piano perfection

The blistering, bluesy guitar of Gary Clark Jr. on his latest album Sonny Boy Slim is sublime. The texture revealed on Clark’s guitar is staggering, awash in reverb, decay and distortion along with a true sense of scale, giving the impression of a live performance. This additional dimensionality not provided by lesser amplifiers doesn’t take the illusion as far.

Listening to a wide range of music for months now reveals no limitation to the GS150’s ability, whether driving Magnepans, the new Quad 2218 ESLs or major floorstanders from ProAc, Dali, GamuT, Dynaudio and Focal. Even the diminutive ProAc Tablette Signatures deliver an otherworldly performance driven by the GS150. Regardless of speaker or cable choices, the GS150 remains perfectly stable, unaffected less than many of the other tube amplifiers we’ve used – some highly particular by the cables used.

Good as this amplifier is, you may notice its capability even more when listening to solo vocals or acoustic instruments. The tonal richness that the GS150 reveals will keep you riveted to your chair for hours on end — always the mark of a great component. Pay particular attention to the way this amplifier accelerates and stops cleanly on a piano key strike or a guitar pluck without overhang or smear, yet retaining a high amount of saturation.

Where some components, especially those with vacuum tubes under the hood, can paint a sonic picture that is a lot larger than life in all three dimensions (And lets face it, that’s why we love tubes in the first place) the GS150 always expands and contracts with the music and the production, never just giving an overblown rendition of everything. Cool as it might be a piano shouldn’t sound like it is ten feet tall. This is another way that the GS150 conveys a realistic portrayal of music.

Chock full of tubes

Where the D-79 uses between 14 and 18 tubes depending on iteration, (there were three models; A, B, and C) to produce 75 watts per channel, the GS 150 uses 4 6H30 driver tubes and four matched pairs of KT150 output tubes to produce 155 watts per channel. As you can see from our photo shoot, at the 11th hour we have acquired a D-79 for some comparison photos, but alas this warhorse is in desperate need of a power supply refresh, so we can’t give you a side-by-side comparison of the sound.  Once it returns from the shop, we will feature it in the Old School column next year and run the classic and the newest model side by side for your and our enjoyment. For now, it’s a wonderful memory to have these two in the same room together!

Let’s not forget the package

Audio Research has always made great sounding gear, but the wives of most of my friends have always seen those big boxes and said “not in my house.” But now with the Italian influence that Fine Sounds brings to the table, this amplifier is gorgeous, as is the matching preamplifier.

Looking at the chassis closely, you can see how much hand work has gone into every facet of this amplifier, from the finish on the front panel; to the delicately lettered power meters and the hand-welded chassis.

Again in the tradition of the D-79 and D-150, the GS150s front panel features three meters: the right and left meter for power output and tube biasing, with the center meter keeping track of incoming AC power. The bias adjustments are on the right and left hand side of the chassis.

Nice as the casework is on the GS150, the same level of attention has been paid to the package inside the familiar, dual box Audio Research packing that long-term aficionados have come to love. To say the tubes are well-protected is an understatement; now they are presented to the owner as a fine wine or cheese. It’s a nice touch, especially at this price level and it’s worth mentioning that the instruction manual is fantastic too. Straightforward, well illustrated and easy to read.

Product of the year, hell yeah

Is this the best power amplifier Audio Research has ever built? For me it is, but that’s being selfish. Discussing the technical features with ARC’s Dave Gordon, I jokingly said that the GS150 is like they built a bespoke amplifier for me, exactly as I would have it look and sound. In the way that Google always seems to know what you are thinking, maybe Audio Research has been probing my thoughts too. To be fair to everyone else, I can safely that the GS150 is my favorite vacuum tube power amplifier.

Buying a great power amplifier is a highly subjective undertaking, especially when a five-figure price tag is attached. If the GS150 weren’t our Product of the Year, it would certainly garner an Exceptional Value Award. If you don’t need 300 plus watts per channel and you enjoy the sheer sound that ARC’s engineers have achieved with the GS150, you’ll never need more amplifier than this. Just like fine cameras, watches or sports cars, there are a number of great vacuum tube power amplifiers available today, yet they all have somewhat different sonic personalities.

If you are an obsessed music lover, I’m guessing you have been on a quest for that “I’ll know it when I hear it” sound, perhaps for a long time. Perhaps longer than I have. If the GS150 touches the nerve that excites that center in your brain, this is an amplifier that you can enjoy for the rest of your life. It is meticulously built — inside and out — by a company with 40-plus years’ experience, execution and support behind them. Should your obsession take you elsewhere at some point, ARC products enjoy high resale prices on the secondary market, and that’s another big part of what makes this amplifier worth the price.  I am thrilled to award the GS150 power amplifier and the companion GSPre our Product of the Year award for 2015. I’m sure 30 years from now it will be held in as high esteem as it is today.

The Audio Research GS150 Amplifier

MSRP: $20,000


Analog Source            AVID Acutus Reference SP/SME V/Lyra Atlas

Digital Source             dCS Rossini DAC, Roon player

Phonostage                  ARC REF Phono 2SE, Simaudio LP810, Pass XP-25

Preamplifier                 ARC GSPre

Speakers                      GamuT RS5, Quad 2218

Power                          IsoTek Super Titan

Cable                           Cardas Clear