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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: Stello CDT 100, Stello DA100 Signature [on loan]
Preamp/Integrated: Glow Audio Amp One 2009, Dayens Ampino
Speakers: Era Design 5, Miu Audio 805, Zu Audio Essence/Druid Credenza, Rethm Saadhana, DeVore Fidelity Nines
Cables: Zu Audio Varial, ASI Liveline speaker cable for the necessary banana connections
Stands: Desk top
Powerline conditioning: Furutech RTP-6
Sundry accessories: Furutech RD-2 CD demagnetizer; Nanotech Nespa Pro; extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: Home office in diagonal table setup inside large open floor plan house.
Review Component Retail: $229 + $40 flat-rate postal shipping charge worldwide
How small is too small? The MiniWatt tube integrated from Hong Kong does beg the question. I can't vouch for its claim of "world's smallest 4-tube amplifier". Greatech's uVac valve unit too is tiny. But clearly, the MiniWatt makes the very short list of contenders. What exactly is appealing about being crowned king of that Lilliputian domain? I'm not sure. I can tell you how such extreme compaction has been accomplished here. It involves an unusual marriage. Think in-house developed switch-mode power supply or SMPS. Then add a transformer-coupled, military-grade Chinese NOS 6J1 (pentode) and 6P1 (triode) single-ended circuit.
From this follow two relevant specs. One, input voltage is flexible. To be exact, it's 85-132VAC or 176-265VAC. That promises greater than usual immunity to under/over voltages. Plus, no power transformer hum. Two yeahs for sure. Two, 8-ohm power output is 2.5 watts. Off the bat, that's not exactly confidence inspiring. It turns the cute footprint of 130 x 100mm and attendant weight of 1.5kg into secondary attention grabbers. Anyone serious about bang for the buck won't obsess about breaking miniaturization records. Who cares about being king of the dwarves? One wants raw performance. 2.5 watts seem more raw deal than muscle. This ain't no portable iPod audio machine even though pricing should appeal to the same core demographic. Alas, what does the average iPod punter know about real rather than bullshit power requirements? Exactly. So the MiniWatt really arrives with a chip on its shoulder. It's got a built-in perception barrier like a big red stop sign. Nay then? Not so fast.
Claimed frequency response is 30Hz to 20kHz within a 1dB window, residual noise is less than 0.8mV. The EI output transformers are Japanese issue. After perhaps a solid "wow, cute" exclamation, the next response any thinking man and woman will level against this proposition has got to be "why bother? What could one possibly do with 2.5 silly tube watts?"
|Derek, director of business development at MiniWatt, is prepared to hit that question on its pin head. His website sports a brief introductory video. In it the MiniWatt drives MBL 116
|speakers with Burmester's 061 CD player as source. While the delivery medium of proof is completely inconclusive (an MP3 audio stream over your PC system, with your own electronics and speakers), the implications are suggestive. The valve complement appears capable of delivering sufficient SPLs in a small HK apartment, over completely unreasonable, big and expensive German speakers. True, 2.5 watts are minuscule no matter the spin. Still, they are considered posh in a direct-heated 45 triode context where one routinely lays out upwards of €3000 for the privilege. Sufficient circuit gain, linear speaker impedance, near-field listening conditions and sane levels all can come together to be perfectly adequate for the job at hand. (High-eff speakers would expand the proposition to big rooms and concert levels but in a normal room, most certainly not for speakers in this price range.) The relevant question remains - will the presumed target audience believe this power rating to be sufficient? What's it really good for?
On job, "...we have an R&D team in mainland China and head offices in Hong Kong. This is our 1st tube amp product." Thus solicited, I opted in. I've got a soft spot for tubes. Ditto for contrarious market positioning. Where a 500-watt solid-state behemoth plays lazily to established preconceptions, a MiniWatt attempts to educate. What's required? What can be done when bling, complexity and excessive power are tempered by conservative reason?
|On infra structure, things began promising enough. Just one day after Friday afternoon dispatch from Hong Kong, the review loaner had already arrived in Switzerland and cleared customs on a Saturday. By Monday the 15th, I had delivery at 8:20 in the morning (without the weekend, I would have had it within one day). If MiniWatt performed as efficiently as the Hongkong Post and its subcontractors, life was good indeed. I did have to pay CHF 50.00 in VAT and import duties so factor in a small customs gratuity when you count your pennies.
On good enough, I instantly leashed up the MiniWatt to my Era Design 5 SAT two-way desk top speakers where the pinkie-size valves stepped in for the 80wpc Peachtree Audio Nova. At 10:30 on the dial, I had equivalent levels. At 2:00, things for the desk top got too loud. The speakers' sensitivity here is probably around 86dB. At 97dB, my Zu Essence had chances of later working like greased lightning in the big rig. The MiniWatt's input sensitivity is 500mV, its gain 18dB, with a 50K input and 8-ohm output impedance. All I had to do here was weigh down the amp and move it off the ledge to not be capsized by the power cord that was lifting it up on its hind legs.
For €229 (albeit with rather higher add-on ship charges from Serbia than MiniWatt's postal flat fee), there's also the 25/50wpc into 8/4-ohm transistorized Ampino. Where most people have been conditioned to want more than just enough, even Ampino's power rating won't blow folks away. But it does seem rather more sufficient. In that very ointment then does struggle our pesky fly called MiniWatt. How to achieve cred with most buyers? I'm not deluded enough to believe that any review will turn around wide-spread preconceptions about factual power draw. Esoteric horn listeners know full well just how far 2.5 watts can go. But shoppers looking to place their best bet with $229? Alas, that's Derek's problem. Mine is sound and comparative context. Will you believe in enoughness? That shall be entirely your burden to carry. Popular opinion certainly speaks against the entire concept hook, line and sinker.
One brief comment on the innards. We always take photos of them. The top plate came off easy enough with the two minuscule output transformers attached. Alas, the flying leads which connect that assembly to the tube circuit board were too short to make for much of a photo op. Suffice to say that the section beneath the transformer cans was fully enclosed in a metal shield to not show anything of significance. The volume control was of the smoothly variable rather than stepped sort, the enclosure got nicely roasty and bananas only may apply on the speaker connections. The included UK-style 3-prong power cord was fitted with a 2-prong Schuko travel adaptor for instant plug 'n' play, the amp itself redundantly protected inside a thick foam clam shell. Receiving the amp from Hongkong and getting it hooked up to play, all potential international issues had been nicely solved in advance. Great start.