Associated Equipment:
Digital Front End
AC Conditioners

Wyred 4 Sound STP-SE Preamplifier

The Balls of Purity


 August, 2012


First off, I don’t like passive preamps. I’ve bought many over the years and, like that unemployed model/actress seated there sipping a 2% skim Chai latte in the local bohemian coffee shop window; they always SEEM like a great idea.

As Rick Shulz, storied designer and tweaker of passives and umpteen other audio gizmos ‘n gadgets said to me over the phone years ago, “how can you beat ONE resistor?!” Well, 20 years later, I’ll tell you how Rick: with many resistors, some capacitors, rectifiers, maybe even a tube or two, and a power supply (or two) all comprising a well designed ACTIVE LINE STAGE—that’s how! Also, with a great buffered passive or auto-former based pre and more recently, with a lossless dithered software-based volume control (ala Audirvana Plus or Pure Music)! Your move, Rick.

That’s how you preserve all the detail and subtlety you, any self-respecting audiophile, are entitled to, while simultaneously helping yourself to kick-you-in-the-pants bass, snappy transients, microdynamics, and PRaT. Sure, Rick Schulz’s EVS Ultimate Attenuators were transparent—incredibly so, but no matter the amp, like that window-candy unemployed model/actress, the EVS Ultimate’s were incredibly alluring initially, and later, let down the side.

They couldn’t speak ‘music,’ just sonics. Every time, no matter my amp, wires or what have you, it has been the same—transparency and then… vacancy; you find out the only book they’ve read in the past ten years is Vogue. (N.B.: size and weight notwithstanding, the September issue does not qualify as a book).

Now, strictly speaking, the Wyred 4 Sound STP-SE is not a passive. It’s a passive/active or an active/passive. That is, it runs in passive configuration up until things get hot and heavy on the volume control and then, at some point, gain is added in. Reportedly, most users rarely get to meet the active portion of this hybrid, and they are therefore primarily listening to passive purity most of the time. Ah, but gain-on-demand isn’t the only trick up designer EJ Sarmento’s sleeve here.

The volume control itself is purportedly a tricked out hyper-pure thing the likes of which only someone with either a masters’ in electrical engineering or whom has read the Wyred 4 Sound website several times slowly can comprehend. I, of course, chose the latter.

It reads: “The easy route (practically everyone else takes) consists of putting audio in and out of a volume control chip. While being cost effective and easy to design, the audio is left at the mercy the chip. The best possible electrical connection that can be made and released on command is made by a switch. The best sounding switch is one that has the least resistance and can maintain at all frequencies, for this we chose to use relays. While much more expensive, slower and noisier when switching, they are far more sonically superior to any switcher chip on the market today. The second part of our volume control is the resistors. That’s right, relays and resistors are the only components interacting with the audio signal. Like all our other products, we use Dale rn55d copper leaded precision resistors. Supplying exceedingly accurate channel to channel level matching (+/- 0.05db) and isolation (>106db), our discrete volume control is the most transparent and spaciously sounding attenuator we’ve heard.”

English major summary: (very) high quality switches (and other components).

Most importantly, especially because it may be the reason many passive pres aren’t so dynamic in a stereo system, and because it’s a concept I almost understand, The W4S STP-SE preamp has a buffer circuit, which is a way to optimize as best as possible, the preamp’s input impedance for your source (it wants to see a high one), while simultaneously allowing for a low output impedance so that your source (generally mainly a voltage delivering device without much current) doesn’t have to work too hard at ‘pushing’ signal through the interconnects and on into the amplifier.

Without a buffer, if your passive volume control has the high input impedance your source likes, it will, sadly, have concomitantly high output impedance. Your source frowns upon this because (drill instructor voice); your source is weak (i.e. low current)!!!!

So, adding a buffer circuit (especially a high quality one) to a passive preamp’s volume control essentially gives you a better electrical match for your amplifier, ensuring your dynamics are snappier, your highs un-rolled off, and your system unfazed by lengthy interconnects, should they be called for. Understand superficially? Sort of? That makes two of us.

Bottom line: a high quality buffer circuit is a great thing to add to a passive pre in order to ensure that ‘balls’ go hand in hand with ‘purity.’

Ergonomically, the STP-SE worked like a charm. It’s so refreshing to find that such a ‘tweaked out’ purist product from such a relatively smaller company is built so well and is such a breeze to use. You turn it on at the back, and after being met with a cheerful greeting on the digital display for your efforts, you depress the volume knob to bring the internals and display on-line. Said digital display is dimmable and extinguishable, and also neatly indicates the selected input (there are five total, including two balanced) and volume level. In addition to precision volume control, the little plastic remote allows for phase switching at the touch of a button (nice!), display dimming, muting, fooling with channel balance, toggling inputs, and turning the preamp on from standby mode.

On the face of the pre itself, input switching is swift ‘n sure by a dint of up/down arrow buttons and the volume knob is one of those fun ‘n free ones you can spin round and round. In actual operation however, that particular behavior is not suggested.

At each incremental turn of the knob you can hear a distinct little ‘click’ from those relay switches inside accompanied by what seems like just the right incremental increase or decrease in the volume of whatever music you’re listening to. I loved sitting there on my couch, pointing a remote at something, pressing a button, and… continuing to sit there.

I know you can do that with any cheap receiver or TV, but I tell you—sometimes the hair-shirtedness of this hobby gets to me. Ya really think a remote control degrades the sound that friggin’ considerably? Really? How come some incredible sounding products like high-end Naim gear and Devialet amps seem none too impaired by them?
Look here at this STP-SE; pretty tweaky and overbuilt, but it’s got a remote and it sure didn’t hurt this preamp any; not to mention the enhancement it provided to my ‘user interface’ along the way. Can’t beat that.

A Sense of Normalcy

Admittedly, the notion of reviewing the W4S STP-SE pre was a daunting one. I mean—this thing supposedly didn’t have a ‘sound’—just the proverbial ‘straight wire with (occasional) gain,’ as it were. What’s to write? ‘I heard nothing (and liked it)?’ For once, there’d be no danger of exceeding my allotted word count.

Well I need not have been scared. Thankfully, I came to feel that like most ‘normal’ components, the vaunted W4S STP-SE pre too has a ‘sound’; not so much a sonic signature it writes large across every album it lets through, but more a general bit of character—like a Victoria’s Secret model’s particular walk or the particular way in which Kevin Costner affects a British accent. Nah—just kidding. The W4S STP-SE is much better than Kevin Costner’s accents—and far more consistent.

That sound, were I forced to describe it in a few paragraphs (and of course, I am), is spacious, airy and well, ballsy, with a bit of tube like warmth—though not nearly as much as a tubed pre. As a matter of fact, in some regards it reminded me of my dearly departed Unison Research Unico integrated or my Lavardin IS Reference integrated. The Unico was punchier and had better bass than the Lavardin, but both were airy, spacious, and a touch warm.

Comparatively, my Burson HA-160D headphone amp/DAC, which I also press into service as a preamp when not using my Audirvana Plus software’s MBIT dithered lossless volume control, seems more up front and a touch less refined, albeit a bit pacier and punchier.

Switching over to the W4S from the Burson on something like the “Bear’’ symphony from the Nikolaus Harnoncourt and the Concentus Musicus Wein orchestra’s Haydn: The Paris Symphonies No.s 82-87 [RCA], you can immediately hear more of the venue in which they are recording—echo off the walls. There is more of that “rosiny glow” around all the strings—more air. Bass drums have a bit more depth and weight to them. Bill Evans and his boys on my fave (everyone’s fave?), Sunday at The Village Vanguard [OJC] seemed to be sitting a bit farther apart from one another and Scott LaFaro’s Bass was moving a bit more air and had a bit more Gravitas than per usual.

In general I could describe the venue and the players within it as a bit more expansive. I could list CD after CD, but essentially, the qualities of the Wyred persisted throughout, whether we’re talking Jazz or Janacek.

In the Burson’s favor, if you like this sort of thing (and I’m a big Burson fan of course), it’s a more forward, pacier device with a bit less depth and width and detail in terms of soundstage and by consequence, a bit less air and rosiny glow attached to the vibrating instruments and voices inhabiting that soundstage. There’s also perhaps a bit less refinement.

Doesn’t bother me none—it’s just that you should know, the Burson pre is more raw sounding; very much like older olive Naim gear, and the Wyred is a more elegant animal—kinda like the newer black stuff. Both have their attendant groupies.

In comparison with my Audirvana Plus software used as a preamp (while the Burson’s Volume remains fixed)—in other words, in comparison with a virtual pre, I still clearly heard the character of the Wyred in that it proved a bit more expansive; a bit warmer and airier, and perhaps had more bass depth. The Audirvana Plus volume control is pretty impressive though, and I of course couldn’t say whether the Wyred’s admittedly attractive qualities are of the sort that are additive, or revelatory.

The Wyred did show some cable preference and it seemed sensitive to cables that were a touch warm to begin with, like the JPS labs Superconductor3 IC’s or the older version of the Skywire 2020 IC’s (which were a bit more heavily shielded than the newest versions, and thus a bit more opaque—if also ‘tomb’ silent).

It much preferred in my system, Skywire’s 1400 series IC’s (less shielding) and Audio Art SE IC’s (not quite as good tonally, but sufficiently lit up). These cable preferences confirmed my suspicion that the Wyred STP-SE is a superb modern take on a tube preamp—without either the tubes, or the opaque pipe and slipper-ishness of some of the components employing them. The Wyred pre was also quite detailed and never in an offensive way—just musically so. I will not say ‘I heard things I never heard before,’ but I will say that it’s been easy to listen for those things via the Wyred if you were so inclined.

I suppose what struck me as especially ‘special’ about the STP-SE is that it seemed utterly transparent, while at the same time giving you a spacious, slightly warm and cavernous perspective on the musical proceedings at hand. As a matter of fact, it seemed as though the STP-SE was sort of a hybrid of another sort; kind of like a cross between a great tubed pre and well, a great passive. All the details were there—but there was none of the passive-like passivity; the dynamic lethargy or sterility. There was also that wonderful bass depth and cavernous, airy soundstage with a mid row perspective and a touch o’ warmth—like a great tube pre.

In “Sigma” (that’s math for sum)…
I’d say the Wyred 4 Sound STP-SE pre lives up to it’s stated intentions. The Wyred is then the first device in my experience that that allies the purity of a passive preamp to the balls of a well-designed (and stiffly powered) active pre.

It truly seems to be a clear as day passive with the dynamic punch, bass and convenience of a well-designed active—sorta like Rick Shulz’s ultra-pure EVS Ultimate Attenuators connected to a huge, over-built power supply in a decent box with a remote. The easy functionality and fuss-free user interface (okay—the remote!) is a major plus as well.

The holy grail then? Pack it up and go home? Well, while a superb overall device, I would say that in my system, the Wyred pre is less mechanical sounding and more refined than the Burson pre (or pretty much any other pre I’ve used, really) and even perhaps a touch more spacious, organic and airy than the digital volume control of my software based ‘virtual’ pre, but the Burson (and the ‘virtual’ pre via the Burson) countered with a bit more pace and transient snap, along with a bit more of a ‘front row’ perspective.

So we’re at the level here of “whadya want?” Heineken or Grolsch? Audio Research or Naim? At this level, it simply isn’t about “better”; it’s about better for you. I’d say if you’re looking at high-end solid-state vs. tubed preamps vs. hair-shirt auto-former preamps and are having trouble deciding, you could really expedite things if you just bought this Wyred pre. Plus, because of the remote, you get to sit on the couch and KEEP sitting there.

Personally, I think Wyred 4 Sound designer EJ Sarmento gave this hybrid “minimalist” thing a remote for a reason—he knew when he built it that if a pre were this transparent to source and offered this kind of a wide open window on the musical proceedings, no one would wanna get up.

I bid you peace.

• Typical Distortion
• THD+N (20-20kHz / 2V) <0.003% THD+N
• Noise (A-weighted / VOL ≤ 63) < 6 V
• Noise (A-weighted / VOL ≥ 64) < 18 V
• Noise (20-20kHz / VOL ≤ 63) < 9 V
• Noise (20-20kHz / VOL ≥ 64) < 27 V
• Frequency Response
• (20-20kHz / 2V) +/- 0.02 db
• Channel Tracking (All Steps) < +/- 0.05 db
• IMD < 0.002%
• Crosstalk (20-20kHz / VOL ≤ 63) >106 db
• Crosstalk (20-20kHz / VOL ≥ 64) > 96 db
• Output Impedance (VOL ≤ 63) 113 Ω
• Output Impedance (VOL ≥ 64) 78 Ω
• Input Impedance 60.4kΩ
• Maximum Output Voltage 9V RMS

Unit Features:
• Input / Output wiring upgraded to Kimber Tcss wire
• 2nd stage filtering caps (4-22,000uf caps) are upgraded to the Wyred 4 Sound Low ESR "SUPER CAP" designed for power supplies
• Vacuum Fluorescent Display (VFD)
• Optical rotary encoder (volume knob)
• Fully functional remote control
• 12V DC Trigger input (to automatically activate HT Bypass mode)
• 2- 12V DC Trigger outputs
• Home Theater bypass (customizable for any input, also DC Trigger input selected)
• Balance control
• Absolute phase control (0/180)
• Efficient (no heat)
• Tripple-ripple reduction circuit contains 164,560uF of capacitance
• Extremely low noise floor
• Fully balanced input to output
• Buffered passive/active design
• Automatically switched in Line Stage (when more volume is needed)
• Discrete volume control using dale RN55d resistors
• Unbalanced to Balanced conversion (when RCA input selected and XLR outputs are being used)
• Idle power consumption = 15w
• Rugged construction
• ” Machined and Anodized front panels
• 60kΩ input impedance
• 3 sets of gold plated unbalanced (RCA) inputs
• 2 sets of gold plated unbalanced (RCA) outputs
• 2 sets of Neutrik Balanced (XLR) inputs
• 2 sets of Neutrik Balanced (XLR) outputs
• Factory Selectable mains 115/230VAC
• Compact size (17”W x 4”H x 13”D)
• 22 lbs.
• Covered by a 3 YEAR WARRANTY
Price: $1,999.00

Wyred 4 Sound LLC
4235 Traffic Way
Atascadero, CA 93422
Phone: (805) 466-9973
Fax: (805) 462-8962