The Wyred 4 Sound SX-500 Mono Block Amplifiers

by admin on September 18, 2009 · 9 comments

in Amplifiers

by Henry Wilkenson

Over the past few years, there has been a marked increase in the number of class D amplifiers brought to market. While class D amps are not exactly new, there use in high end audio systems relatively is. The biggest advantage that class D amps have over other amplifier classes is efficiency; they are typically upward of 80% efficient or better. As a result, they usually are smaller and lighter in weight. Another advantage is that they will afford audiophiles on a budget the opportunity to take a big bite out of the “High-End Sound” apple, at a much lower price than would otherwise be possible. Now, I’m not going to tell you that you that for 2K, you will be able to obtain the performance equivalent to a pair of Pass Labs class A monoblocks, or anything else in that class. You will, however, be able to achieve a very high sound quality for a fraction of the price you would have had to pay a few years ago.

Wyred 4 Sound is a relatively new company that is operated by Cullen Circuits. Cullen has also been manufacturing products for companies such as PS Audio, BGW and a wide range of other high-end manufactures since 1990. W4S products are designed by EJ Sarmento, and manufactured by Cullen Circuits. Wyred’s SX 500 monoblocks are the subject of this review.

The primary design goal of Wyred 4 Sound is to produce high quality, high performance components at real world (affordable) prices. The current SX series amplifiers are in fact a refinement of their initial offerings. The 14GA chassis and thick aluminum top cover and ½ inch anodized front panel, make it apparent that the build quality of the Wyred 4 Sound products is very high. According to the manufacturer, the case work provides a solid foundation for the very robust internal parts. Some of these parts include, MUSE audio grade capacitors, WBT speaker binding posts, Dale copper leaded resistors. The amps are very well built in a practical sense. That is, sonic performance is the primary objective. They are not unnecessarily over built, which would only result in higher production costs.

The SX-500’s are powered by modified ICE powered engines. The manufacturer goes on to say that this engine accounts for only 80% of the sound quality. The input stage in conjunction with other internal modifications is responsible for the additional 20% of performance. According to Wyred, all of these elements combine to account for the unique sound of the amps.

When powered up, all you will see is a restrained blue lighted strip on the front panel. The light is unobtrusive which is a good thing in my opinion. Along the rear panel from left to right is a circuit breaker, IEC A/C input, power switch, DC trigger, RCA and Balanced inputs and a pair of very high quality five way binding posts. The binding posts are spaced very close together, which might pose a problem for very heavy speaker wires that are terminated with large spade connectors. They are however, perfectly spaced for use with dual banana plugs. Installation and set-up is simple and straight forward. Given their size, they require very little shelf space. Since in my case where space is at a premium, this is a most welcome benefit.

I only listened to the SX-500s casually during the burn in period which I estimated to be around 100 hours. I never expect too much from a component sonically until the burn in has been completed. There have been several instances when I was pleasantly surprised by what I heard from a component right out of the box; this was another of those times.

The first thing I noticed right out of the box was how quiet these amps were.  Perform the ear to the speaker test and, nothing, just silence. This low noise floor is in large part the reason these amps have the extraordinary ability to retrieve low level detail. Many details that were previously buried are easily revealed by the SX 500’s.

With the first CD, the SX-500s floated a very wide and deep sound stage. Images were well defined within the stage and at times extended beyond the speakers. The images were rounded in a way that made the entire sound stage seem more natural.

After the burn in period had passed, just about 100 hours, sonically, things became better. The treble was extended and detailed. Cymbals in particular had good shimmer and decay. I had a clear and solid sense of the stick or brush on metal. Again, the SX-500s excellent presentation of detail is quite evident. Well recorded live recordings such as Keith Jarrett’s “Up For It” [ECM 1860 B0000406-02] or Alex Blake’s “The Alex Blake Quintet, Now is the Time, Live at the Knitting Factory”, [Bubble Core Records, bc-030], you can really hear the ambient room cues of these live recordings. This kind of resolution creates a strong sense of that “you are there” quality that makes these types of recordings so much more enjoyable.

The bass performance of class D amps tends to be their strong suit. These amps are no exception. The bass is tight and deep. As with other areas of the sonic spectrum, it is also very well detailed. is also very good. The rich timbres of upright basses, is particularly notable.

The range from top to bottom is well balanced. No one area jumps forward or is recessed. I can also say that these are among the most transparent amps that I have ever had in my system.

With dynamic recordings, if its dynamics that you are after, you will find it here, nothing in this regard is held back. It’s not surprising with 35 amps of current available. I put a pair of Ear to Ear Music Cable, speaker wire in the system and things only got better. The sound became even more dynamic with greater tumbrel weight and transparency. All of the positive characteristics that I heard were enhanced with these cables. I think that you will be hearing a lot more about Ear to Ear in the future.

Overall, the SX-500’s are very listenable. While I would describe the overall presentation as being on the slightly cool side of neutral, they had me going through my collection listening and re-listening to CD after CD.

I will seldom call any component an audio bargain but, in this case, the description applies. At $1,798 per pair, that’s exactly what they are. These amps can easily compete with gear costing more than twice as much. Wyred has a great deal of confidence in their products since they offer a 30 day trial period. Should you decide to return them, there is a 15% restocking fee. Check out the web site for complete details.

As I said earlier, the competition on the class D front is heating up rapidly. I feel The Wyred 4 Sound SX-500’s can fair very well against the best out there.

Wyred 4 SoundSX-500 Mono Blocks

MSRP $1,798 per pair
3 year warranty
Power- 250 watts into 8ohms
550 watts into 4ohms
Maximum output current 35 Amps

Associated Equipment:

Digital Sources:
Sony 777ES  SACD Player (modified)

VAC LE Pre Amp
NuForce Pre Amp
Gilmore Raptor Power Amps

Dynaudio 3.3


Wasatch Ultama Speaker Cables
Acoustic Zen and Von Gaylord Audio Chinchillia Interconnects and Speaker Wire

P.S. Audio Power Plant Premier

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{ 6 comments… read them below or add one }

paul basinski 07.09.09 at 6:12 pm

Good review.

admin 07.09.09 at 8:28 pm

Thanks, Paul. And welcome.

Please check your email.

Cheers, a

Andy Fawcett 07.10.09 at 8:24 pm

enjoyed the review, thanks, with just one question - when you describe the W4S as sounding “on the slightly cool side of neutral”, do you feel that this is a general trait with Class D amps (or specifically the ICEpower module), or was the W4S notably cooler sounding than others that you’ve heard/owned?
Catch you, Andy

Henry Wilkenson 07.14.09 at 10:30 pm

Hi Andy,

Thanks for the kind words. To answer your question, I found the W4S amps a little dryer when compared to the Gilmores. The Gilmores have more timbral fullness but they are not as transperant. The W4S are more dimensional and go lower in the bass. Overall, it’s an interesting comparison.

Henry Wilkenson 07.14.09 at 10:32 pm

Hi Paul,

Thanks for the comment. I’m glad that you enjoyed the review.

PJL 02.06.11 at 10:41 am

The wyred for sound is very nice for the price but is still somewhat behind the Spectron and in my opinion the Digital Amplifier Company is now the best out there beating all class of amps and sounding tube like somewhat in the mids
Affortable audio did their Cherry Jr at $2k which is their mid priced unit.

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