Reviewer: Srajan Ebaen
Source: Zanden Audio Model 5000 MkIII DAC; Accustic Arts Drive-1; Audio Aero Prima DAC [on review]
Headphone amp: Emmeline II The Stealth [on review]; SinglePower MPX3 [on review]
Headphones: audio-technica ATH-W1000; Sennheiser HD 650
Cables: Stealth Audio Varidig S/PDIF, Stealth Audio Indra; Crystal Cable Reference speaker cable and power cords; ZCable Hurricane power cords on both conditioners
Stands: Grand Prix Audio Monaco four-tier
Powerline conditioning: BPT BP-3.5 Signature; Walker Audio Velocitor for source components
Sundry accessories: GPA Formula Carbon/Kevlar shelf for transport; GPA Apex footers underneath stand; Walker Audio SST on all connections; Walker Audio Vivid CD cleaner; Furutech RD-2 CD demagnetizer; WorldPower cryo'd Hubbell wall sockets; Mapleshade 4" solid maple platform under BPT conditioner
Review component pricing: $849 base price; $1,118 as configured/delivered

Alert: It has since come to our attention that SinglePower and its proprietor have a poor track record for taking people's money without delivering in a timely manner or at all. This link to HeadFi details some of the evidence.

When the Berlin wall crumbled, a divided Germany reunited in the aftermath. Many of its former Eastern workers had been used to decades worth of lax Communist work ethics without any attractive material rewards. They had a grizzly of a time adjusting to Western-style capitalist heat. Darwinist survival in such a competitive climate equates to "big dog eat little dog unless little dog run faster". But little dog can't simply run to hide underneath mama's petty coat and cry the Blues. He can't grab the Vodka, tread water and wait in a daze for 5:00PM to clock out. He's gotta face his adversaries and do teeth-to-jugular combat to carve out his own turf. Work harder and longer than the guy across the street and perhaps you stand a chance of making it. While consumers revel in the broad choices this enables and flash entitlement like a club membership badge, we in the West often forget how brutally cut-throat our free market economy really is. Today's review component is the direct outcome of competitive spirit and home-based entrepreneurship. Think husband-and-wife team of Russian/German descent. They've nestled into the promises of our US-based specialty audio cottage industry to spend their daytime hours on something they're fiercely passionate about. Survival in these leagues depends on hard work, superior value and strong word-of-mouth until mainstream press coverage steps on the accelerator.
SinglePower's MPX3 from Denver/CO arrived by postal service rather than UPS or FedEx, bolstered by miles of bubble wrap rather than its own molded foam inserts. It was packaged in an over-the-counter mail carton instead of its own dedicated factory box but was securely dispatched and received without so much as a scratch. Speaking with designer Mikhail Rotenberg on the phone, I learned that he used to hang out with radio operator WWII vets as a kid. He secured his FCC amateur radio operator's license at the tender age of 15 to later experiment with broadcast transmitter/receiver modifications before designing phono preamps for friends. He holds degrees in Electrical Engineering and Computer Sciences. About 17 months ago, he formally launched his SinglePower business in earnest while initially supplementing the fledgling outfit as a day-time computer programmer. Unexpectedly strong and rapid word-of-mouth on Head-Fi has since grown the company to four full-time employees, a 2,500sft facility and about 150 chassis on the shelves.
According to Mikhail, the MPX3 is currently his most popular model, in the exact upgrade variant I had received. Over the base unit, it adds Solen fast capacitors ($65), Jensen paper-in-oil coupling caps ($154) and the Neutrik locking 1/4" headphone jack ($50). I first became aware of this amp through a reader who owns it and suggested it might be right up my thermionic headphone alley. The very reflective, high-gloss black, hard powder-coated amp is said to be compatible with phones from 32 to >600 ohms. The output-transformerless MPX3 sports a tight-action continuously adjustable Noble volume pot, a headphone socket and power mains on the front panel and one pair of high-quality RCA inputs and an IEC power inlet on the rear. The top houses a capped 100VA/600V center-tapped EI-laminate power transformer, two 650uf supply capacitors and three 6SN7 triodes in military-spec ceramic sockets with silver contacts. The first valve is the driver, the second and third one left/right channel buffers respectively. Total gain of the Class A, zero NFB, point-to-point wired MPX3 is 21dB depending on which exact 6SN7 tubes you run. Parts & labor warranty extends to 36 months.

The unit includes military-grade RN65 Vishay resistors; multi-stage capacitive filtration with polypropylene film, film & foil and paper-in-oil capacitors; and a "heavily filtered and rectified DC heater supply". Power supply regulation is via a 300-watt, 23-amp hi-current Mosfet with current and short circuit protection. Power supply capacitors include units at 650µF @ 500VDC (x2);15uF @ 450VDC (x5); ,47uF @ 630V (x1); and 4700uF @ 35v (x2). AC power requirements are factory pre-configured but an optional dual-voltage international panel switch is available. The amp is put together of a heavy-gauge bent aluminum U-shape that seamlessly covers the guts front to back and bolts to a 90-degree rotated and lidded bottom U via a total of four small hex screws front and aft. SinglePower sells and recommends the following valves for the MPX3 (pricing per tube): Current-production Electro-Harmonix' at $15; 1943 KenRad VT-231s at $115; 1951 Hytron 6SN7GTs at $105; 1954 Hytron 6SN7GTs at $75; and Sylvania VT-231s at $98. Warm-up time for the amp is 5 minutes (30 minutes optimal) while break-in time is 100-200 hours, with initial conditioning performed at the factory.
Because of pending patents, Mikhail requested that I not publish candid shots of the insides. Asked what he offered beyond the MPX3, I was introduced to the $1,699 Supra -- commonly sold between $2,000 and $2,200 with the most popular upgrade options installed -- followed by the $3,200 Maestro above and lastly a 65lbs $6,500 beast simply dubbed the SDS (is that short hand for surely da shit?) of which only five or six units have sold thus far. Both top models incorporate 99dB-efficient Vanderveen-designed power transformers which SinglePower commissioned directly from transformer specialist Plitron in Canada.

As one climbs up inside the SinglePower model chain, overall gain reduces, resolution increases and power supplies grow more and more extravagant. The Supra already enjoys 250 volts of headroom to increase energy-on-demand times and thus speed and stiffness while its screen voltage actually drops by 50 volts below the 315V of the MPX3. (The tubes in the above image are Mullard CP181s at ca. $200/ea., a higher-emission variant of the 6SN7 that draws roughly 1.5 times its current.) SinglePower recently acquired an established vendor of high-quality audiophile parts for which manufacturing has already shifted in-house. Watch Mikhail's website for pending announcements. He further divulged that he's been in R&D for quite some time now on an OTL tube amplifier that will produce about 65 watts into 8 ohms and is claimed to be unconditionally stable into any loudspeaker load.