The List: Five of the Best Power Amps in The World

Welcome to something new we’re going to try here on PTA thanks to our friend Wynn Wong of Wynn Audio in Richmond Hill, Ontario. I’m going to be curating a new list every month featuring different categories of gear that I think you – our readers – have to hear under any circumstances you can arrange: beg, borrow, steal, drive for hours, hop a train, take a plane… you get what I’m saying. Price will not be a factor, with individual pieces on each list reflecting a spectrum of what I feel is the best. This new feature will be called… The List, and it will be my attempt to share some of the gear opinions I’ve managed to accrue spending as much time as I do (apologies to my family, and friends) with high fidelity equipment. Items featured will include at least one piece of gear that I’ve personally spent time with, so it’s not some random list put together without context. I hope you enjoy reading them as much as I enjoy putting them together.

–Rafe Arnott, Instagram: @audiophile.gentleman

Karan Acoustics 400 KA S power amplifier.

If you’ve been following the course of this series then you’re familiar with the disappointment the Internet displayed with my list of CD players, the scorn which was heaped on my list of turntables, and the revulsion my list of pickup cartridges engendered. This month I’m focusing on power amplifiers, and I expect the comments, and private responses to my choices to continue in the vein of disbelief of what I’ve chosen as Five of The Best power amplifiers in the world. Again, I repeat that this is not a definitive list of The Best power amplifiers on the planet, but merely those I feel are among the best. Again, as I wrote previously, there will be many of you who question my choices, and wonder aloud at what I didn’t choose, but please bear in mind this is a list with room for five choices, so it’s inherently designed to thrill some, and disappoint many.

CH Precision M1 power amplifier I had for review.

So, what exactly are we talking about here? The power amplifier has been around for quite some time, with pervading lore suggesting Lee De Forest brought it kicking, and screaming into this world about 1912 following his invention of the triode vacuum tube – valves for you classy UK folks – in 1907. It’s got one thing to do: Amplify the delicate, low-level electronic audio signal from a pre-amplifier, and source reproducing the original, recorded event, and send it on to a transducer where a crossover network will divvy-up that signal into highs, mids, and lows. It does this in a variety of ways, ranging from – as I mentioned earlier – vacuum tube-based amplification of the signal (think 300B, EL34, 6L6GB, F2A, etc.), to solid-state technology employing transistors like MOSFETS (metal-oxide semiconductor field-effect transistors), JFETs (junction gate field-effect transistors), FETS, or BJTs (bipolar junction transistors).

The List is brought to you by Wynn Audio.

Early days saw tube power amps as ubiquitous, but with new technology solid state became de facto for many hifi enthusiasts because it ran cooler than valves, was deemed more reliable (a point a would beleaguer another time), was cheaper to manufacture, and produced far greater output in watts than tube-based amplification designs. Now, in part, the race for ever more watts from an amplifier came about as more, and more loudspeaker manufactures turned away from traditional high-efficiency large-baffle, single driver, or two-driver speaker designs that needed only a handful of watts to drive them in an effort to make transducer cabinets narrower, and more presentable to a changing home decor aesthetic in the ’70s. Big, boxy speakers were out, tall, thin ones were in, so as speaker efficiency went out the door to compensate for smaller enclosures, and ever more complex crossovers, the need for more power from an amplifier grew exponentially: Hence the solid-state proliferation that started in the late ’60s, and continued for the ’70s, ’80s, ’90s, through today albeit for a still strong, but smaller market for those audiophiles who prefer valves.

400 KA S in situ at my place.

The power amplifier – be it designed to work in two-channel, or stereo mode, or single channel, or mono mode (requiring two amplifiers, one for each stereo channel) – could be considered a somewhat unique beast in the high fidelity world in that it is usually reserved these days for those souls who prefer separate power, and pre-amplifiers in their signal chain. It can also be prodigiously large, bulky, and of back-breaking weight, with many tipping the scales at more than 100 lbs. It’s sole purpose by design is to deliver power. Many audiophile enthusiasts covet fewer boxes in their component count, and thus rely on the integrated amplifier which houses both a pre-amplifier, and power amplifier in a single chassis. While this arrangement can make just as dynamic, nuanced, powerful, and musical a presentation of the recorded event as separates in many configurations, as I said earlier, it usually falls to the separate power amplifier, and pre-amplifier to put forth their combined efforts for the most discerning, or purist audiophiles.

The Focal Sopra No.2 I paired with the 400 KA S.

As both an avid tube, and solid state fan, my personal reference system is now valve-powered – it wasn’t always that way though – but I have had many of my most delicious listening sessions within the context of a system driven by solid-state pre-amplification, and power amplification which is why this list consists of a mix of tubes, and transistors. There are many loudspeakers I love which require the grunt of a power-amplification stage consisting of hundreds of watts, just as there are those transducers which fare best with the more modest output of a valve output stage, so without further ado, please consider these personal power amplifier choices as Five of The Best in The World… according to me.

McIntosh MC601 mono block amplifier

McIntosh MC601 mono block power amplifier.

The iconic glowing blue VU meters which grace the glass fascias on McIntosh amplifiers are legend not only in the hifi industry, but out in the world at large too. Instantly recognizable as a statement of sonic fidelity, and a commitment to what many concur would signal a serious stereo system. McIntosh has been making some of the highest-quality audiophile components in Binghamton, New York since 1949, so they can safely be considered a luminary in the field of amplification as far as I’m concerned. The McIntosh MC 601 has been around in its current guise for several years now, (It’s being replaced by the new MC611 which boasts numerous updates, including a doubling of filtering capacity, which according to McIntosh has yielded a 55 per cent increase in dynamic headroom) yet shows no signs of aging. It outputs 600 watts into either two, four, or eight ohm loads using McIntosh’s Autoformer™ technology. It’s a Quad-Balanced design for the entire throughput, and can be bi-amped or tri-amped, features 0.005% measured distortion, and weighs in at a svelte 93 pounds (each). I’ve heard MC601s in a number of systems over the years at shows, and regardless of the load required by the loudspeakers they were driving, the 601s always gave a big, ballsy presentation with the ability to handle massive dynamic swings, and deliver on the most subtle acoustic nuances. Whether it was rock, classical, jazz or a lone vocalist playing guitar, the 601s never missed a beat, and always seem at ease, giving the listener an impression of limitless headroom. MSRP: $14,000 USD/$17,900 CAN/pair.

Shindo Cortese F2A stereo power amplifier

Shindo Labs Cortese stereo power amplifier.

Shindo Labs is a name revered in the hifi community for exquisite sonic capabilities. The hand painted, wine-bottle green chassis, rare French wine naming convention, and most importantly, their circuit designs based around rare, vintage tubes set them apart. Often spoken about in hushed tones for the all-too-human playback capabilities their amplifiers are capable of producing, there is surprisingly little information available online regarding circuit specifications. I had been reading about the hand-built, boutique Japanese high-fidelity component company for years, but unfortunately their gear is thin on the ground in my part of the world so I had only heard one of their pre-amplifiers, and stereo power amplifiers up to a few months ago. They had become my personal Elvis-Presley-sighted-at-Walmart meme because I felt like I’d never hear another Shindo pre/power combo again. Then I got the chance to visit with Jonathan Halpern of Tone Imports – who brings Shindo into North America – and Matthew Rotunda of Pitch Perfect Audio in Los Angeles where I spent some time with the Shindo Cortese F2A stereo power amplifier, and the Monbrison pre-amplifier. This system was fronted with the Shindo 301 Vinyl Playing System, and feeding into massive field-coil powered Shindo Latour loudspeakers. As the first notes of a Jimmy Hendrix cut started playing it was like an AC cable had been plugged into my spine. The visceral, palpable, speed of attack on notes was thrilling, ditto for bass, percussion, and vocals – the diminutive 10 watt F2A-powered Cortese was a timbral dream, and fleshed out the bottom end like few other power amps I’ve heard. When combined with the Latour’s massive, short-throw 15-inch field-coil woofer, this was a pairing that caused my arm hair to stand on end. MSRP: $12, 250 USD/$16,400 CAN.

Karan Acoustics 400 KA S stereo power amplifier

Karan- KA-S-400
Karan Acoustics 400 KA S stereo power amplifier.

Not a name known to many, even those in the know look at me sideways when I mention Karan Acoustics, but this Serbian company has been quietly making bespoke integrated amplifiers, pre-amplifiers, and power amplifiers for many years. Lead engineer Milan Karan uses custom-spec’d components in his circuit designs, many of which are built by industry leaders who supply original equipment manufacturers. Utilizing a dual-mono topology, fully-balanced circuit paths, DC-coupling, ultra-low internal impedances, and pure Class A operation, the 420-watt (into eight Ohms) Karan Acoustic 400 KA S stereo power amplifier is one of the most musical solid-state amplifiers I’ve heard. Capable of recreating the most dense passages with ease, the 400 has a delicacy to woodwinds, stringed instruments, and piano notes that is completely effortless, and natural in its presentation. With a total of 16 Sanken RET (ring-emitter transistor) output devices (eight per channel), the 400’s total current capability is 160 Amperes, meaning it can drive pretty much anything without breaking a sweat. Having experienced the 400’s big brother the 600 KA S driving Tidal Audio Sunray loudspeakers, and Penaudio Serenade Signature speakers, I was excited to have the 400 in-house, and chose the Focal Sopra No.2 to pair with it. I wasn’t disappointed, with the 400 providing a level of bass definition, midrange punch, and imaging that I’ve come to expect from power amps at twice the price. MSRP: $18,000 USD/$24,000 CAN.

CH Precision M1 stereo power amplifier

CH Precision M1 stereo power amplifier.

This is a power amplifier I’ve spilled a fair amount of ink over already, so including it in this list was a no-brainer for me. The Swiss-designed, and built CH Precision M1 stereo power amplifier is one of the most flexible power amps on the market today. The M1 can be run in multiple modes: stereo (single chassis, this is what I ran), monaural (two chassis, with one chassis/one channel powering one left/right transducer) bridged (two chassis, with one chassis/two channels  powering one left/right transducer) passive bi-amplification (two chassis, with one chassis/two channels powering one channel per transducer in parallel) active bi-amplification (two chassis, requires two analog input boards to be installed – one per chassis – each chassis channel drives a transducer a given frequency range), and daisy-chain mode (a chassis for every transducer, one chassis/one channel powering one left/right transducer). From my review: The M1 features a patent-pending ExactBias Circuit that monitors internal temperatures of power transistors, and adjusts (in real time) their amplifier’s bias, to the ability to adjust (in 10 per cent increments) local, and global feedback for controlling the amplifier’s damping factor to fine-tune it to any pair of speakers – got transducers with drivers (tweeter/mids/bass) that need to be driven independently? Perfect. The feedback ratio can be adjusted for each driver. Weighing in at 165 lbs, with an absolutely massive 2,200 VA transformer which CH engineers have fully isolated from not only electrostatic, and magnetic interference, the transformer itself is also separately-mounted internally on “Silent Blocks” for full mechanical, and vibration isolation of all the internal circuitry. Discrete components are used throughout the amplifier, with no operational amplification in the analog stage, and no capacitors, or output relays in the signal path. This is an amp for music lovers. Just the way a Rolex Submariner is the destination of a lifetime for some, so too could the M1 be for those inclined to such precise measurement of fidelity to source. MSRP: $51,000 USD/$63,960 CAN.

PS Audio BHK Signature 300 mono block amplifier

The PS Audio BHK Signature 300 mono block amplifiers.

Squat, massive, and incredibly overbuilt, the PS Audio BHK Signature 300 mono block amplifier (namesake of audio engineering legend Bascom H. King) is a take-no-prisoners power amplifier that delivers 300 watts into eight Ohms, 600 watts into four Ohms, and more than 1,000 watts into two Ohms. Featuring a zero-loss parallel vacuum tube-input stage in conjunction with a differentially-coupled, paralleled, balanced-MOSFET output stage, the Signature 300 has the chops to drive immensely difficult loads. I’ve heard this amplifier in several system demoed at various hifi shows over the past couple years, and came away incredibly impressed on every occasion. An effortless presentation to every recording is a hallmark of PS Audio in my experience, with speed, dynamics, and an innately natural, unforced sound to everything from heavy metal, to intimate acoustic guitar solos. King seems to have harnessed the best of both worlds (tubes, and solid state) in this design, and the fact that it’s made in the USA by real people, for living wages is further proof of company founder Paul McGowan’s commitment to delivering high fidelity with integrity. When paired with the company’s pre-amplifiers, and power regenerators one takes the depth of lensing the recorded event ever further into the abyss of musicality. Powerful, authoritative, yet delicate, and organic, the Signature 300 strikes a balance not common in the audiophile world. MSRP: $14,998 USD/$19,220 CAN/pair.