Wyred4Sound MC4 Power Amplifier review

Wyred 4 Sound MC4 Power Amplifier


  • Powered by ICEpower ASP technologies
  • FULL OUTPUT THD+N < 0.01% Power doubles in 4 ohms
  • 2 ohm stable
  • 83 % total efficiency @ FULL OUTPUT
  • CCIF Intermodulation distortion = 0.002%, 19kHz/20kHz
  • Damping factor = 2000, 100Hz, 8 ohm
  • Factory Selectable mains 115/230VAC
  • Stand-by power consumption 4.1W per channel
  • 12V DC Trigger in and out
  • Gold plated unbalanced (RCA) inputs
  • Neutrik Balanced (XLR) inputs
  • XLR ground lift pushbutton
  • High Pass ON/OFF pushbutton (Front right and left channels) Dimensions: (17.25”W x 8”H x 16”D)
  • Warranty:3 years Made in USA
  • Price: $2795


Wyred 4 Sound (W4S) is a California based company that designs, engineers and manufacturers a range of amplifiers intended to achieve high-end audio quality at less than typical high-end prices. Launched from Cullen Circuits, the design and engineering firm that built and services products for many other companies (including PS Audio, Genesis and others who prefer to remain anonymous), the W4S brand now includes a series of class-D amplifiers, covering monoblock, stereo and multichannel configurations with a variety of added features. The company can tailor the amp to your specific needs and offers combinations of power and features that make W4S line of products very audiophile friendly.

All W4S amps are built around the ICE power module originally designed by B&O, and common to many of the newer switching or Class D amps. W4S claim to have found ways of improving the basic sound though proprietary circuit modifications including dual balanced FET input stages utilizing zero feedback, and power supplies using oversized low equivalent series resistance (ESR) MUSE capacitors. According to information they supplied, all critical signalpath resistors are hand matched Dale Rn55d copper leaded, non-magnetic resistors which W4S claim provide the best sonic performance. Add in RF suppression, high strand copper for short wiring paths and effort put into practical modifiability rather than finished aesthetics, and you begin to get a sense of the niche W4S aims to fill. This is an Affordable$$Audio -kind of company. Early buzz on the various audio forums is positive, and you can purchase direct from W4S or through their one online dealer, Underwood HiFi.

I listen in an 18 x 24 x 8 room with hardwood floors, large rugs, soft furnishings and a wall of LPs, CDs and books on one side, windows on the other, so I discussed the options with the ever-responsive EJ Sarmento, partner in W4S, who upon learning of my desire to try biamping my Von Schweikert VR5s, suggested a four channel configuration in their standard multichannel amp chassis. We settled on 2 channels (labeled ‘rear’) providing 500w for my woofer modules, and 2 other channels (labeled ‘front) providing 125w to the mid/tweeter modules. At a list price of $2795 it is priced at about half what my reference two-channel BAT VK500 retailed for before it was replaced with the newer (and now far more expensive) VK600.

When I say W4S is customer-oriented, I mean it, as this was one convoluted review that required lots of help to make it happen. EJ is a frequent discussant on the AVS forum set up for Wyred products (methinks an Audio Circle would be better but that’s just my view) and he always gives timely, informative and polite answers to the sometimes cranky participants, even agreeing cheerfully after a couple of prods from people to change W4S policy on 30-day home trials, a practice originally seen as cost-prohibitive for a small, low margin, start-up manufacturer. My experience in obtaining the amp is a great example of how this company works. I requested the specific four-channel configuration via email on Sunday night, no less, and received a reply within an hour. The amp was built for me the next day, shipped Tuesday, and arrived in Austin TX on Thursday of the same week. Talk about a quick process! Unpacking was easy, especially if you are used to a monster amp. Double boxed and well cushioned for delivery, I opened the W4S MC4 up and had the amp installed in about 20 minutes, needing only to fuss around the back of my preamp (the PS Audio GCP 200 with external power supply) to make sure I was connecting all four cables correctly. Given the matching (if unusual) layout style of the Wyred and the PS Audio connectors, the mapping was easy enough. I had to use a couple of pairs of old MIT T2 single ended interconnects for this as I had only one pair of my usual PS Audio Resolution balanced cables to hand and it is important to use the same interconnects for all four channels to avoid gain inequities.
So straight away I was probably handicapping the W4S, but I ordered a second pair from PS Audio to have the chance to check this for myself, as I shall mention later.

Wyred 4 Sound MC4 review

Setting up MC4

The multichannel amp is rather utilitarian looking in plain steel grey with black edging overlaying part of the face. It looks somewhat better in real life than in photos, and while it will win no awards for beauty, the blue power light gives the amp a certain understated elegance. Still, you know where your money is going and it’s not on audio jewelry. The MC4 came with 4 pairs of inputs, 2 pairs single ended, two balanced. Push-buttons switch between these inputs and you need to use them to make sure the signal is correct (on one occasion I unintentionally changed a setting of one input when checking my cables and nearly drove myself demented trying to figure out what happened to my soundstage). There is also a high pass filter on the ‘fronts’ (the channels driving my mids/tweeters), which assists biamping by (optionally) eliminating low frequency signals to the ‘front’ channels. The manual and website are a little unclear on exactly how this is achieved (the filter is reportedly set at 80Hz and 12 db per octave but is has a subtle audible effect and I used it).

Wyred4Sound MC4 Power Amplifier back

I had several minor adventures setting it up, from hum, power shorting and even having new modules put in to review a different configuration, all of which, I can attest, had nothing to do with the W4S product or its reliability and everything to do with my fussing about and trying everything. For example, I enjoy a pair of Virtual Dynamics David power cords feeding my dual-IEC BAT, relishing their obvious benefits over the stock cords, even as I curse the weight and inconvenience of these metal snakes. Deciding to remove one of the variables at work in this amp comparison, I tried at first to use a David on the single outlet W4S MC4 (note: the images on the Wyred4Sound site show the MC amps has possessing 2 IEC receptacles, so I was surprised when mine arrived with only one, but EJ assured me this would not be important and that the 2 corded version, available if someone really wanted it for 4 channels, made most sense only for the fully loaded seven channel MC). But as I wrestled the David into the wall, the outlet sparked, triggering a breaker and shutting everything down. Ouch. Cue concerned emails to both VD and Wyred, both of whom responded within minutes, and I mean minutes, guiding me through a couple of checks and to the conclusion that the David’s sheer size and weight had probably strained the outlet out of position, shorting the circuit, resulting in a tripped breaker and possibly a scorched outlet at worst. Now think about this – how many industries do you know where the companies will respond in minutes to a customer who has a problem like this? My query to VD had the owner, Rick even offering me his cell number to call if I needed to be talked through the check of the circuit. Now that’s customer service!

To cut a long story short (and it is a long story), I eventually had everything working and ran the original W4S for at least 150 hours before making any real comparisons but even then, I had been advised the amps ideally required 300 hours of break-in (that’s a lot of time if you are playing music a few hours a day only, so the 30 day trial will really require you to let the amp play when you are not around). The minor hum problem I experienced for the first few days, which EJ worked tirelessly to help me solve, was stopped first by removing the ground pin in a PS Audio cord which I ended up using on the amp, and later by using balanced interconnects between pre and power amp, at which point the ground pin could be returned or even the VD David used on the W4S without a problem. This is likely something in my system or RCA interconnect not the amp but it was ultimately a simple fix and EJ was as passionate about solving the problem as I was.

The Sound of MC4

Enough already, so what did the music sound like now (and I mean the music, not the amp, which now sounded eerily silent and cool, you’d have a hard time knowing it was on without the blue light)? There are a couple of distinguishing elements that remained constants in my time with the Wyred 4 Sound MC4, even with a later re-configuration, which I will describe below. First, and most noticeable, was the clarity of the bass. The W4S seriously tightened and toned the bass, rendering notes quickly and articulately, without decay or overhang. After years with the rich bass reproduction of my BAT I certainly took notice. The good side of this is that bass drum figures in rock music became more distinguishable; as if you could hear four clear beats from a kick drum where before there might have been a blur of percussion. The best way I can describe this is to say that if you consider a bass note to have a duration, the Wyred seems to start and stop these notes faster so that one can easily follow more precisely what the bass player or drummer is doing. In contrast, my reference, which is no slouch in bass, seems slower and perhaps fuller, fleshing out each note to the point that it becomes harder to know which note is which, though you can certainly hear and feel the presence of bass. I came to recognize in the BAT less silence or space between the bass notes, but clean distinctions with the W4S. Over time, this impression was confirmed, but not always favorably, depending on what music was playing. Take the wonderful Metheny/Haden collaboration, Under the Missouri Sky. This is a recording that can sound superb or flat, depending on the quality of your system and I use it routinely to test components, especially speakers. The tone of Haden’s double bass on the Wyred MC seemed at times over-tight, as if the wood body of the instrument was stuffed or deadened, the resulting bass more hard-edged and short-lived. If you play a string instrument you learn quickly the difference plucking a string near the bridge can make to the sound: it becomes shorter, with less tonal depth, less resonance from the instrument’s body. This is what even electric bass played on the Wyred could sound like on many (but not all) recordings, and while it gave the bass notes some precision and clarity (e.g., when listening to Steve Ray Vaughan’s Texas Flood, I was impressed by how easy it was to follow Tommy Shannon note for note, showing how much support his playing provided to the music’s driving rhythm) this stiffer clarity was not always pleasant to my ears, lending the music a sort of sharpened edge. So you gain speed and delineation but at the price of harmonic information in the bass region, the first obvious trade-off in this design.

On the midrange is a similar trade-off. I was worried the W4S would sound sterile, as some critics have suggested must be the case with this technology. I am not so sure. Starker’s cello playing on the SACD of Bach’s Unaccompanied Suites is light, airy and lovely to hear on the Wyred, though not as full bodied as on the BAT. In return, the Wyred provides a clearer window to the musician’s bowing and emphases. A completely different genre such as James McMurtry’s ‘Where’d you hide the body?’ album had the Wyred pulling out other details from the music that I had not previously noticed; and on Holly Cole’s Temptation, her band seemed to be more nimble and quick with the Wyred than with the BAT. The Cole recording is an interesting one – I once had a dealer switch this off when his Wilson Sophia/ tube amp combo boomed the bass on this recording, mumbling that the album was badly recorded. It is not but it does stretch your system so you can learn how well set up everything is in your room. With the W4S in place, there was no boom here, only deep, tight bass, a sheer joy to behold, and a clarity to Cole’s voice that offered a slightly different perspective on the recording than I am used to with the BAT, rendering her lighter, a little more throaty than chesty (if I can say this). Which perspective is correct? I am not sure you can answer this without resorting to the invocation of personal taste, but it’s a choice you have to make if you go this route.

Class D amps have been often negatively reviewed for supposedly curtailing upper information, losing air and space in the important upper regions. And for sure, on some recordings this is true of the Wyred 4 Sound MC4. One is the Tord Gustavsen Trio’s Being There, where the drums play a vital role in punctuating the music with soft airy cymbal touches that give air and life to sparse passages. I am used to hearing these floating above and around the piano and bass in a lush and distinctive manner (especially with the Virtual Dynamics power cords in place). Sadly, on the W4S these sounds lost some of their sparkle, sounding flat in places, not shimmering in the air and decaying at length but sounding more percussive and even stunted in places, as if the cymbal was stopped short. Playing with the rear tweeter settings on the Von Schweikerts (a handy feature) could restore some of the glory but the Wyred never matched the BAT in this regard. Similarly, drums could sound overly thin and hard, without the skin and shell resonating as in life and therefore coming across as flat and hard. With piano, there seemed to be more air around the notes of individual keys with the BAT, the richness of tone seemed to cause the sound to linger in the air, more palpably there. These are small details but they matter in giving timbral accuracy to the music, and once taken away or lessened, I suspect most listeners would miss them.

When I mentioned this perception of upper air flattening to EJ, he told me that I might prefer other modules for the fronts, which W4S had determined offered preferable sound for most people. This involved swapping out the 250ASPs in my set up for a pair of 200ASC modules to drive the uppers, which, EJ described as producing a lusher more tube like sound. Well, what’s a curious reviewer to do? I decided this had to be explored so off to CA went the amp to return in two weeks with a new pair of 200ASC modules. If you order now, this is the configuration you will get as standard.

Of course, new modules require break-in so that’s what I did. I put the amp in place and racked up over 350 hours before I seriously listened again. EJ even suggested my original impressions of the first configuration might shift over much longer break-in than I had given the original modules, so this time I was determined to leave nothing to chance. Over the course of the next few months the amps tacked up over 600 hours of use on them, the bass modules even more. The new modules, frankly, sounded awful when I first put the new W4S to work – cold, hard, and unpleasant for the first couple of hours but miraculously, these started to ease up quickly, and left powered on, the amp started to change before my ears. Be warned. After several hundred hours it was clear, these new modules definitely offer a softer, airier top end than the pair I had originally heard. By 300 hours I recognized this was a far better set up to my ears and tastes, keeping the tight low end I’d experienced already but not foreshortening the top end as before. If you have the originals, you might want to check with W4S about this modification, I cannot imagine most people preferring the ASPs.

You always want component changes to have obvious, dramatic benefits or at least deficits that confirm the choice one way or the other but in my experience, this is not always the case and one has to live with a change for some time, especially with high end, well designed gear, to get a true sense of their contribution. I left this amp in my system undisturbed for weeks before going back to a comparison with the BAT. One very odd impression I noted was that I could tell the difference between these amps easily when I was in an adjacent room. The Bat seemed to fill the spaces of my house more, somehow. It was not a volume issue; it seemed to provide more spreading air that signaled to the next room there was music of a certain kind playing. The Wyred never sounded that good from another room. It faded out without extending far. Physically impossible? I don’t know how else to express it but I continually experienced it.

Certainly the W4S is cleaner and tighter, offering almost laser-like clarity in the bass region. The BAT, however just seemed to give me that pleasant, fuller sound that made relaxing into music easier, particularly in some crucial areas such as cymbal and drum reproduction, the fullness of the piano or the decay of plucked strings. I’d switch back and forth some days between the amps and find details and resolution on recordings with the W4S that I’d not appreciated before, the breathing cycle of a flute player on Davey Spillane’s Pipedreams, the shift of Metheny’s fingers on a guitar neck, all made a little more obvious by the Wyred’s detailed presentation. But the BAT would go back in and I’d find that mellow warmth in the mids and uppers to be just better sounding to my ears. Du Pre’s cello on Elgar’s Concerto in Eminor is the latest case in point. It’s a pleasure to listen to on the W4S but it comes alive in my room through the BAT.

Wyred4Sound MC4 Power Amplifier back review

Since I left the W4S in my system at one point for over seven weeks without using the BAT, I found an intriguing variation on the stock reviewing process that employs favorite recordings. In that window of time I bought new music, which I listened to only on the W4S, such as Pat Metheny’s Day Trip (with Christian McBride on bass and Antonio Sanchez on drums) and John Surman’s The Spaces in Between, and listened a lot to both until I really had the music in my head. When swapping the amps, I would now hear the BAT against the W4S on music I’d only heard on the MC4. It proved an interesting experience. Even with the 200ASC modules, the BAT still gave the music more upper life and as a result, at least on the Metheny album, on certain tracks the band seemed to possess a swing that was not previously evident on the W4S. I know, how can we measure ‘swing’ or even explain it. I can’t except that the music had a collective flow that had not made itself obvious to me before I played it through the BAT. But it’s these small, odd details that separate the two amps, and while I could live with either, pretty happily, I find those little extra aspects of the BAT’s reproduction to matter in my room.

Yet sound staging, where it’s present on the recording, was clearly superior with the W4S. This may be one of the inherent advantages of biamping but with the MC4, once set up correctly, the singer sat in the middle of the space between the speakers and music came from around and behind to give the impression of depth and height that improved on what I was used to hearing from the BAT. This may not matter to you and will surely be dependent on the type of music and quality of recordings you listen to routinely. For me, sound staging is an important part of creating the illusion and enhancing the experience of music in my own home when I sit down to listen. I rarely enjoy systems where the music so obviously comes from one speaker or the other. The W4S gives you such a clear window onto a tangible soundstage that it could make many other amps sound muddy.


The Wyred 4 Sound MC4 is a good amp and an excellent value. Its bass reproduction and control are impressive and the nimble, comparatively lean sounding mids provide oodles of detail on recordings that you might have missed in the past. It is an easy amp to live with, never running warm in the midst of a Texas summer, never giving me a problem through multiple cable and connection changes, and for the power on hand, it is remarkably light and easy to move. It takes a considerable number of hours to reach its best, those 300 hours are not an exaggeration, but at the price, I don’t know where else one looks to find four channels of obviously better amplification.

I have reservations however about timbral accuracy and the reproduction of upper frequencies in comparison to my reference. Acoustic guitar, which I play, is very good on the Wyred though bettered by the BAT, while the mid and upper ends of piano often seem a little stilted on the W4S, the notes not as fleshed out or present as with the BAT. I feel the Wyred offers greater resolution in the lower range, allowing the listener to hear details that might not be so clear on the BAT but the BAT has the edge in terms of relaxing the presentation and not drawing attention to details as much as enveloping you in music played by instruments of more substantial body.

The 200ASC modules narrow the gap between these two amps in most respects but price, but it never gets the W4S MC4 all the way there. This is not to say Class D cannot compete with the best of A/B designs, it’s probably more a case that the BAT is just plain exceptional (as it should be at more than three times the price, let us not forget). That W4S can so obviously tailor the sound across the spectrum suggests this technology is just waiting to be refined further. Certainly the MC4 is cable-sensitive (the XLR connection with PS Audio Resolution and Transcendents balanced interconnects was so much better than the RCA connection with MIT cables that once installed I never went back. However I heard less noticeable change with any power cord I used, from VD David to PS Audio Plus). Since W4S is so responsive to customer wishes and options, I am tempted to ask if upgraded connectors, a dual power-cable design, or separate chasses for the amp modules might push the W4S amp in small increments towards even better sound? Maybe. As it is, the MC4 is obviously a fine amp for many tastes, it offers buckets of clean power, great sound staging, and exceptional resolution at a comparatively affordable price. Having owned a pair of Legacy Sig III’s, I’d bet the W4S would be a fine match for their warmer sound than the resolving VR5s I now own. W4S is definitely onto something with their designs, for many people these will be all they amp they need but given the people behind the company, I suspect we shall see further innovations that push the boundaries on what this technology can provide. You want lots of power, low maintenance, no heat, easy placement and complete configurability in an affordable package? Welcome to the world of W4S.

Associated Gear:

  • Marantz SA11-S1, SACD player VPI Aries, JMW 10, Benz Glider 2, PS Audio GCPH for phono
  • Ps Audio GCP200 pre amp with external power supply
  • PS Audio PPP for line conditioning
  • Virtual Dynamics and PS Audio Plus SC power cords throughout,
  • PS Audio Transcendent XLR and RCA cables, MAC Silver Braids for vinyl. (MIT T2 RCA, Monster RCA)

external link: MC4 @ Wyred 4 Sound website

from affordableaudio, By Patrick Dillon