Preview: Woo Audio WA234 Monoblocks

Sixteen very large bills for a pair of very large amplifiers that make up a headphone amplification system.  Don’t think of it as crazy money for a headphone amplifier, because the WA234 can drive a pair of efficient speakers when configured with 300B output tubes.  Think of the WA234 of the way to get an SET amplifier that sounds better than a $125,000 pair of Wavac amps for the price of a slightly used VW Golf.  That’s our rationalization.

-Jeff Dorgay

Woo Audio WA234 Monoblocks


McIntosh C500 Control Center

McIntosh has always built preamplifiers that define the term “input flexibility,” which is why I always refer to them as control centers.  With nine inputs and six variable outputs (two XLR and four RCA) in addition to a processor loop, it’s safe to say this preamplifier should be able to accommodate every source in your system.  It also features a MC and MM phono stage that can be configured from the front panel or your remote control, so no stone is left unturned.  MSRP for the C500 is $12,000 in either the solid-state or tube version.  You can buy all three boxes for $18,000, but the C500 controller can only access one preamplifier at a time.

A two-box design, the C500 has an interesting twist for those having the age-old debate about the validity of solid state versus vacuum tubes; you can configure your C500 either way.  It’s actually two preamplifiers, the C500P (solid state) or C500T (tube).  The flagship C1000 controller offers the same choices and allows you to drive both preamplifier modules simultaneously, but with the C500, you have to draw a line in the sand and pick one.  For those on the fence, your McIntosh dealer should be able to audition both.

While McIntosh does an excellent job at voicing their gear similarly, there is still an elusive magic to the tube sound that is tough to ignore, and while a vacuum-tube preamplifier means that you will have to change tubes from time to time, it’s nice to have the option.  The end user is the winner thanks to this unprecedented ability to fine-tune your system, even to the all-McIntosh customer.  And both two-box designs feature a set of big, blue output-level meters.

A fully balanced design from input to output, the C500 uses eight 12AX7 tubes: four in the high level circuit and four more in the phono preamplifier.  The phono preamplifier circuit is all tube if you are using the moving magnet (MM) stage. If you have a lower-output moving-coil (MC) phono cartridge, the MC stage uses McIntosh’s own solid-state phono step-up modules instead of an input transformer.   Four of the 12AX7’s are visible from the front panel, back lit in green, while the other four are beneath the top cover.


The controller section of the C500 has no tubes inside and generates almost no heat, but the preamplifier section does get a little bit warm with eight tubes inside, so make sure to give it some ventilation room.  Once both boxes are unpacked, you will notice a pair of umbilical cords that look like parallel-interface printer cables from the earlier days of PC-based computing.  According to Ron Cornelius, McIntosh’s Sales Manager, there are only control voltages running through these cables; “There are no audio signals here.”  So for the tweekophiles in the audience, put your fears aside.

The single IEC power socket is located on the controller chassis, which also houses the dual power supplies for each channel, making the C500 a true dual-mono design.  For those new to the McIntosh fold, these power transformers are wound in-house, as they always have been.

Once power is attached, the C500 stays in standby mode and on power up, displays a “tube warmup” message on the LCD front panel, with the outputs muted.  Worth noting is that the C500 does not produce a harsh transient, should you forget and shut the preamplifier off before your power amp.  A nice touch, especially should you be using an amplifier with significant power output.

If you are incorporating the C500 into an all-McIntosh system, there are seven individual data ports so you can link your other components to the C500 and control them all from the one remote – very cool if you have come to the point where you are considering hiring a feng shui consultant to keep your remotes in order!  The C500 also features 12V trigger ports, so you can turn everything on with the single power switch.  A great feature with other amplifiers but very impressive on a large McIntosh system when you see all of those blue and green faceplates light up at once.

Most of my listening for the review period was conducted with the MC275 vacuum-tube power amplifier and the MC1.2 KW solid-state monoblocks, and with a variety of speakers.  The system was cabled entirely with Cardas Clear and utilized the balanced connections on all but one input (The dCS Paganini).  After the initial listening was complete, I swapped the standard-issue power cord for a Python CX from Shunyata, as I use on my reference Burmester preamplifier.

How about that input flexibility?

It doesn’t stop with the number of inputs.  The C500 allows you to trim the outputs of each program source +/- 6db and you can do it from the comfort of your listening chair, making it easy to fine tune the system so there are no surprises when going from CD to tuner, etc.  Seeing that McIntosh has put so much effort into the display programming, it would be nice to see this taken a step further to let the user fully customize the input readout (a-la BAT or Simaudio). It would be great for those with multiple turntables and digital players to be able to have the display say “Rega P9” instead of “Phono MM.”

However, you can rename the inputs to the preset CD 2, Aux 2, etc. and you can shut off the display on the inputs that are not in use. So if you have only three inputs, you will only be switching between the active ones to avoid confusion.  The display has seven steps of brightness from which to choose, and the meters can be switched off for those who like to listen in total darkness. But the question begs to be asked: why would you ever want to switch off the meters on a McIntosh?

The MM phono stage has adjustments for capacitive loading from 50pf to 750pf in 50pf increments.  As there are a number of high-quality MM cartridges on the market, this allows to perfectly optimize your MM cartridge playback.    The MC phono stage allows the input resistive loading to be set at 25, 50, 100, 200, 500 and 1,000 ohms.  This should cover the bulk of MM cartridges that are available, but for the hard-core turntable enthusiast, it would be nice to see a “custom” setting that can be set by a competent technician.

Should you still own a high-performance tape deck or other recording device, the record and listen processor loops will come in handy.  I found this to be indispensable using the Manley Massive Passive studio EQ, when capturing digital files from my favorite LP’s for music-server use.  Thanks to the C500’s playback loop, I could sneak the Manley into the system to use with troublesome CD’s for playback as well.  While this is a feature that few will use, those with multiple sources will appreciate it.

Definitely sounds like a McIntosh

Almost all McIntosh gear has a full-bodied sound that leans slightly to the warm side of neutral, but I can’t ever think of an instance where it isn’t welcome.  I’ve heard other preamplifiers with more resolution, but the C500 offers a great balance between the lush, overly tubey sound of the ’60s and a modern high-resolution sound.  While a few of your most pristine, perfectly recorded discs (analog or digital) may not have the last bit of slam and dynamics as they might on a more resolving preamplifier, I’ll bet that at least half of the records in your record collection will benefit from that extra tonal richness that the C500 offers.  This is one of the main reasons for the fierce loyalty of McIntosh owners.

But don’t think the C500 doesn’t hold its own against the competition.  When listening to the GamuT S9, the YG Acoustics Anat Studio II, the MartinLogan CLX and recently the Estelon XA (all very high-resolution speakers in the $30,000 – $140,000 range), I never felt the preamplifier was holding the system back.

When comparing to my reference Burmester amp and preamp, the tubes had a definite warmth, but it was always inviting.  Male and female vocals came alive in a way that they only seem to do with tubes – there was just more of a third dimension available.  Listening to Neil Young’s voice on the 24/96 version of Harvest was easily discernable from the standard 16/44 copies.

The soundstage of the C500 was always BIG.  This seems to be so much easier to accomplish with vacuum tubes, and if you listen to a lot of rock and contemporary jazz that is created in a studio with a somewhat artificial soundstage to begin with, the C500 will win you over on this aspect alone.  Listening to “Woman in Chains” from the Tears For Fears album, The Seeds of Love, the triangle played during the opening of the song appears to float about 10 feet beyond the speaker boundary.  It’s not real, of course, but it is cool.  If you love classic rock, you will be in heaven with the C500.

Solid-State or Tubes?

By far, the most intriguing feature of the C500 is it’s ability to work with a vacuum-tube output stage or a solid-state one.  As I suspected, the solid-state version had a bit more punch and the tube stage was slightly mellower.  The solid-state preamp section also had slightly more weight in the lower registers.  When listening to some bass-heavy tracks from Tosca, utilizing the JL Audio Gotham subwoofer, the tube section had a slightly looser feel, whereas the solid-state version offered a bass perspective that would more punch you in the chest.  If you have a system capable of going down deep (the Gotham is only down -3db at 16hz) and perhaps listen to a lot of electronica, the solid-state version might be for you.

While I could happily live with either configuration, I did gravitate more towards the all-tube preamplifier with the MC 1.2KW solid-state monoblocks and the Octave MRE tube monoblocks (which are somewhat “un-tubey” sounding), while the solid-state output stage was more to my liking with the MC275 vacuum-tube power amplifier and my Conrad Johnson MV-50C1, which each have a fairly warm overall tonal balance.
Though definitely a great subject for a month-long internet forum argument, deciding which one of these two is right for you is immaterial.  The good news is that you have the option.  Should your needs change, you can go to your McIntosh dealer and purchase the alternative.  Upon reconnecting all of your other components and the umbilical cord, a simple reset on the front panel and the C500 will make the necessary change.

Spinning records

C500 owners who have just one turntable and perhaps don’t swap cartridges often won’t be able to take advantage of one of this preamplifier’s best features: the ability to set loading from your listening position.  Cartridge swaps are a weekly occurrence here, and many audiophiles will have removable headshells or tonearm wands that use a specific cartridge for different purposes or as the mood strikes.  The more-involved vinyl junkie will be right at home with the C500.

I managed to try almost a dozen different phono cartridges from the Shure M97xe all the way to the Clearaudio DaVinci, all with excellent luck.  The only cartridge for which I could not get the perfect match was the SoundSmith Sussaro, which is a moving-iron cartridge that sounds its best at about 2,500 ohms.  There are a few moving-magnet cartridges that also perform a bit better slightly above or below the standard 47k loading, but these are the exception rather than the rule for 99.9 percent of analog users.  Most MC cartridges should easily work between 100 and 1,000 ohms (though the 25 ohm setting is a fantastic match for the Rega Apheta MC).

Thanks to the solid-state modules in the MC section, the C500 is quieter than an all-tube phono stage and has a healthy dose of dynamic punch as well.  A tiny bit of background noise creeps in to the C500’s phono stage, but you have to put your ear right up to the tweeter to hear it.  The solid-state modules in the MC section aren’t just switched into the MM signal path.  According to the engineers at McIntosh, there are two separate phono stages under the hood of the C500.

While listening to Joni Mitchell’s Wild Things Run Fast, (the recent ORG pressing), I found there was a wonderful midrange bloom to the presentation that made Mitchell’s voice take over the soundstage in a very enjoyable manner.  I had similar results with any other strong vocalists in my record collection.  Playing Marquise Knox’ Man Child on LP was a chilling experience, revealing enough of his vocal character that you just might be fooled into thinking that you are back at Chad Kassem’s Crossroads Blues Festival.

Comparing the phono stage in the C500 with some of the outboard phono stages we’ve had the opportunity to live with during the past few years, it offers a level of performance that would cost you $2,000 – $3,000 in an outboard phono stage. A separate MM and MC stage is pretty much non-existent at this price, plus you probably would want to buy an upgraded power cord along with a pair of decent interconnects going from phono stage to linestage.

Don’t forget the phones

McIntosh doesn’t ignore the headphone users on any of their preamplifiers, and the C500 is no exception.  While not the last word in headphone performance, you would have to spend somewhere between $500- $1,000 to get an outboard headphone amp (and remember, more cables….) to put this one in the weeds.  Running the gamut of the AKG 701’s, Grado GS-1’s, Sennheiser 650’s and my new favorites, the Audeze LCD-2’s, I came away impressed with the C500’s performance.

The headphone stage sounded identical on both output sections, leading me to believe that the phono board is identical in each. Though it would only benefit a small number of customers, it would be cool to run the tube output stage direct through the phones.  If you are like me and enjoy headphone use from time to time but don’t feel the need to invest in a multi-thousand-dollar headphone setup, the C500 should serve your needs just fine.

Looks great, sounds great

McIntosh has stayed true to its look and feel, so the big, backlit glass front panel and blue meters will either speak to you or they won’t.  The C500 is rock solid.  It’s been playing here for about the past six months, 12 hours a day without so much as a burp, and I suspect that it will continue to do so just as so many McIntosh preamplifiers do out there in the world.

The best reason for buying this preamplifier is its combination of performance and flexibility. Whether you ultimately make one the cornerstone of your system depends on whether you can make use of what it offers.  There are a few $12,000 linestages out there that will extract more music from your recordings, but none of them have a built-in MM and MC phono stage, or a built-in headphone amp. So the C500 ends up being a little spendy if you don’t need the phono stage and a killer bargain if you do.  It’s also nice to know that should your amplification needs change, you can fine tune the C500 with some tube rolling or even change the output stage to solid state.  -Jeff Dorgay

McIntosh C500 Control Preamplifier

MSRP:  $12,000 – $18,000


Analog Sources Rega P9/RB 1000 and Shelter 501II cartridge    Oracle Delphi V/SME 309    Grado Statement cartridge
Digital Sources dCS Paganini stack    Sooloos Music Server    Naim HDX
Power Amplifiers McIntosh MC275    McIntosh MC1.2kw monoblocks    Octave MRE 130 monoblocks    Burmester 911 mk.3    Pass Labs First watt F2    Conrad Johnson MV-50C1
Cable Cardas Clear speaker cable and interconnects
Power Running Springs Dmitri and Maxim power conditioners    RSA and Shuynata power cords
Speakers GamuT S9    MartinLogan CLX    YG Acoustics Anat II Professional   Estelon XA     B&W 805D w/JL Audio Gotham subwoofer

AudioQuest DragonFly

I’ve been having way too much fun with the AudioQuest DragonFly—so much fun that it’s taken me all year to write the damn review.  This nifty little device has quickly become a must-have travel accessory.  And although I’m perhaps not as sexy as George Clooney, I am on an airplane these days almost as much as his character in Up in the Air—but fortunately I never have to fire any of the people I’m visiting.

Here’s how it usually goes:  The minute we hit 10,000 feet and the pilot signals that personal electronics can now be used, I pull out the DragonFly and whatever phones I’ve brought along for the ride.  Before I can even get the cans on my head, the passenger in the seat next to mine asks, “What is that? I’ve never seen one of those. Is it expensive?”  And I’ve had just as many female as male passengers inquire.  On the flight home from the Munich High End show, I just happened to be sitting next to an audio nerd who was terribly impressed.  “How did you get one of those?” he asked.  It turns out that he was a loyal TONEAudio reader, which always makes for great conversation.

After a quick listen, everyone comes away convinced that they need a DragonFly—even Bose noise-cancelling headphones users, and that’s saying a lot.

What Makes It So Awesome?

We could go on and on about all the techie bits that make the DragonFly so special—like its 24-bit/96-kHz Sabre DAC, on-board headphone amplifier and built-in digital volume control—but that would be kind of boring.  (For those wanting such techie bits, read Art Dudley’s excellent review in the October issue of Stereophile.)

Beyond its technical achievements, the DragonFly succeeds on many levels.  It sounds way better than its $249 price tag suggests, but the real triumph of the DragonFly is that it’s accessible.  You don’t have to be a mega-nerdtron to understand it (or use it, for that matter), but if you are a true audio enthusiast, you’ll immediately grasp its gestalt.  Among the 100-plus parts inside this tiny music machine, which is barely bigger than a USB jump drive, are Sabre ESS DAC chips, a pair of clocks and a 60-step digital volume control.  The USB connector even uses the same silver coating as AQ’s premium USB audio cables.

But you’ll forget all of that the minute you plug it in.  I’ve used a couple of excellent portable DAC/headphone amplifiers, but none of them are conducive to traveling light.  The DragonFly requires no power adaptor, cables or accessories; just plug it right into your laptop’s USB port, direct your computer to use it as the sound output and you’re rolling.  It works equally well with Mac or Windows operating systems.

My review of the DragonFly begins with my current traveling companions, the Sennheiser PXC 450 noise-cancelling headphones.  Starting with Bombay Dub Orchestras’ 3 Cities, in straight 16-bit/44.1-kHz mode via iTunes, there is a major jump in sound quality that instantly eliminates some of the fog that always accompanies noise-cancelling phones.  With the already spacey vibe of this album, the presentation is definitely more hallucinogenic via the DragonFly.  Driving guitars, courtesy of Black Sabbath’s Paranoid, quickly nudges me back into audiophile mode, as I listen to the big improvements the DragonFly makes to Apple Lossless files through noise-cancelling headphones.  The cymbals in “Fairies Wear Boots” have a smooth, natural timbre through the DragonFly that make me want to goose the volume up a bit higher than might be prudent—so be careful:  The lack of graininess and distortion catches you off guard at first.

Flying always makes me impatient, so I often bounce back and forth between music, movies and Angry Birds, but thanks to the DragonFly’s virtual elimination of listener fatigue, I’m listening to complete albums—something I rarely do on a plane.  I save the playlist from this trip so I can compare tracks when back in the office with a full compliment of other headphones.

Better Phones, Better Results

With the impressive performance that the PXC 450s turned in, I’m not prepared for what the DragonFly is capable of with my cache of over-ear headphones.  Should I start at the bottom and work up, or the other way around?  Decisions, decisions.  Patience gets the best of me and I jump right in with the Audeze LCD-2 planar phones and upgraded Cardas Clear headphone cable.

Yeow, this is incredible!  Even with 16-bit/44.1-kHz files, it’s like strapping a pair of Magnepan 1.7s onto my head, with a First Watt amplifier on my back—which would not be convenient or fashionable.  School Food Punishment’s Air Feel, Color Swim gives the LCD-2s a great workout, with layer upon layer of well-sorted vocals and synthesizers.  Switching back to the headphone jack on the MacBook Pro is now unacceptable—the additional resolution provided by the bigger phones is too much fun to be without.

There’s more texture and decay everywhere.  The bongos at the beginning of William Shatner’s rendition of “Space Truckin,” from Seeking Major Tom, now feels like it’s being played through a great pair of loudspeakers, and I find myself forgetting that I even have headphones on.

High-Resolution Files: The Final Frontier

Upping the ante to recently downloaded files from HDtracks shows just how much the DragonFly is capable of.  The latest version of Pure Music software is a night-and-day upgrade from the standard CD-quality files I have on hand of Herbie Hancock’s classic album, Head Hunters.  The beginning of “Watermelon Man” now has air on the acoustic instruments that wasn’t there before, and the bass line now has plenty of it’s own space and texture.  Those not convinced of the validity of higher-resolution digital files need not purchase a five-figure digital rig; the DragonFly and a great pair of headphones will make you an instant believer.

As my next-door neighbor, who knows nothing about audio, shouted while listening to the 24-bit/96-kHz version of Fleetwood Mac’s Rumours, “I like this a lot better!” (Funny how people shout when wearing headphones, isn’t it?)

Having auditioned a wide range of great DACs in the $1,000 range, I can tell you that the DragonFly easily competes.  It has a decidedly “un-digital” sound, with an ease that should appeal to even the most hardcore analog lovers.  At the risk of offending the analog loyalists, I will say that if I were putting together a system on a modest budget, I’d much rather listen to even Red Book CD files through the DragonFly than cobble together a $249 analog solution and play gnarly records found in the budget bins.

Eliminating the casework and power supply from the parts count (and no doubt some profit margin) goes a long way at getting the price down.  Bravo to AQ for delivering this product for such a down-to-Earth price.

Anchor Your Audio System

If the DragonFly were only a headphone amp, it would be a major bargain at $249, but it’s equally exciting used just as a DAC.  Mated to the Sansui receiver and JBL speakers (covered on page 77), and an earlier-generation Mac mini purchased on eBay for about $100 bucks, I managed to create an amazingly musical system for just under $1,000 total.  In this case, the fixed analog output of the DragonFly works well, taking the digital volume control out of the equation.

Picking out the ethereal Fairlight sounds on the Tubes’ Completion Backwards Principle is an exercise in trippiness.  Things were floating all around the imaginary soundstage in my head.  Not able to stop there, Eno’s Ambient 4: On Land dragged me further into the world inside my head—one that is typically only provided by listening to headphones.

Moving further upscale, to the system in room two, which is now configured with a Conrad-Johnson PV-12 preamplifier, Krell KSA-50 power amplifier and a pair of Dynaudio Confidence C1 II speakers, the DragonFly still cuts the mustard.  On a recent visit to the KEF factory in the UK, I had the pleasure of experiencing the DragonFly in KEF’s reference system with a pair of its flagship Blade speakers ($30,000/pair). Impressive!

No Longer Outside Looking In

There’s no better gateway drug for the world of high-quality sound reproduction than the AudioQuest DragonFly:  Just add the laptop and the headphones you already own and prepare to be blown away.  Or plug it into your current hi-fi system and use it as a high-resolution DAC—it’s all good.

If you spend as much time on a plane as George Clooney and I do, or if you are just an avid headphone listener, you need a DragonFly.  If you aren’t an avid headphone listener, I’ll bet you quickly become one with the DragonFly on hand.  And playing Angry Birds has never been more fun.  Bahooonga!

I am very happy to announce that the DragonFly is our Product of the Year in the digital category.    -Jeff Dorgay

The AudioQuest DragonFly

MSRP: $249