August 1, 2003

By Art Thompson

The expression “marvel of miniaturization” rarely applies to modern tube amplifiers, most of which are still as cumbersome as the ’50s and ’60s classics that inspired them. But stompbox maker Zachary Vex has radically changed that reality with the Nano Head ($439 street), a palm-sized tube amp that uses a pair of new-old-stock Phillips 6021W dual-triodes (originally made for use in ballistic missiles) to pump out a half-watt of power. Designed to drive an external speaker cab of your choice (preferably 8 or 16 ohm), the Nano Head is also equipped with a 1" plastic speaker that emits— make that spits—sound out of a trio of holes drilled in the bottom plate of the aluminum enclosure. A 12-volt adapter is included with the Nano Head, and you can also power it with a car or motorcycle battery. To increase headroom and dynamic response, the Nano’s internal voltage is stepped-up to 230 volts via a Vex-designed circuit that generates enough heat to require fan cooling. In the event of thermal overload, an LED lights up to indicate that the self-resetting fuse has tripped.

Nano Construction
The Nano Head’s tubes, transformer, and can-style filter caps are well protected by a quintet of “roll bars”—two of which also keep pressure on a small plastic tube shield (easily removed if you don’t plan on carting the Nano around much). The small bottles, which are about an inch tall and slightly larger than a pencil in diameter, can be replaced by the user on all units with serial numbers of 100 or higher (an optional tube-pin alignment kit is required for this task). Earlier Nanos have soldered-in tubes, which require factory servicing. Tube maintenance shouldn’t be much of an issue with this amp, however, as the 6021s were designed to withstand the severe G-forces imposed by a missile accelerating from zero to 30,000 mph in a few seconds. Doubtful that a stage drop will be able to hurt these tubes!

Viewing the Nano’s internal organs simply requires removing the four screws that secure the bottom plate (an act that technically voids the two-year warranty). Residing in the cramped space is a PC board that grips most of the circuit components, aside from the jacks, volume pot, and output transformer (the same type used in a Fender reverb circuit), which are case-mounted.

Mighty Mite
The Nano Head sounds surprisingly stout for such a pip-squeak. Connected to a Marshall 4x12 and tested with Strats, Teles, a PRS McCarty, and a Schecter PT Custom, the Nano delivered thick, meaty distortion tones with the volume maxed, the 3-position Mellow switch on the “white cloud” setting, and the 3-position Thickness switch set to the human figure with the fat belly. In this full-bore configuration—and driving four 12s—the Nano Head is still very easy on your ears. It’s a little too loud to talk over, but nothing compared to the aural assault of even a similarly configured 5-watt amp. The dynamics are happening, too—back off your guitar volume and the tones clean right up.

Though armed with few controls, the Nano Head is quite flexible. For example, setting the Mellow and Thickness switches to “sunny” and “skinny” yields a crisp, bright tone with ample clean headroom. From there, you can get a jazzier vibe using the “dark cloud” setting (a configuration that also worked well for bass) or, by setting the Thickness switch to “normal,” a grinding blues tone. The bright switch is pretty subtle, however, and it made little difference when using either humbucker or single-coil guitars.

The Nano Head is pretty quiet, though a tiny amount of buzz is noticeable when you put your ear right up to the speaker. If you’re a freak about such things, you can opt for the multi-voltage power supply ($65 street), which nukes the noise and self-adjusts to any wall voltage you encounter when traveling abroad.

Quiet Storm
Though the Nano Head’s ability to deliver a useful range of clean and distorted tones is impressive, the thing that truly stands out about this micro tube amp is its ability to deliver the “beef” at levels that won’t make you the pariah of your apartment complex. Whether you record at home, or simply wish to rock out in your living room with a fat, juicy sound reminiscent of a muzzled Marshall, the Nano Head delivers the low-volume mass you crave. This is good, because unless you plan on running the Nano Head into a speaker emulator or reactive-load box, the only way to capture its tones is via a miked cabinet. Smaller speaker cabinets—such as the Celestion Blue-loaded 1x12 open-back we used—help to further reduce the Nano’s volume impact. And if you really want to get small, there’s always the amp’s miniscule internal speaker, which, with its hilariously crappy sound, is a lo-fi effect unto itself.

The Right Stuff
While some will argue that the Nano Head does nothing that can’t be accomplished with a good distortion pedal and a practice amp, there’s no denying the unmitigated coolness of this midget tube head. Bringing the big-amp experience down to HO scale is no mean feat, and doing it with an honest-to-God tube circuit that delivers the right dynamic goodies gives the Nano Head a leg-up over most pocket-sized, amp-emulation devices.

Then there’s the XY-factor of this little device, which, with its chrome roll-bars and hand-painted graphics is about as cute and cuddly as a piece of gear gets. And, man, when you fire up the Nano Head and watch those dinky tubes start to glow, you can’t help but appreciate the effort it took—roughly three month’s worth by Vex’s account—to make this tiny terror a viable deal. It all adds up to a small step in tube-amp evolution that could have a big impact on your quest to rock the house—quietly.


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