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It became obvious quickly just how capable of a performer the Ai500 was after a brief conditioning period had shed some initial brittleness. Making an appearance in the review of Hegel's H-100 integrated, the Norwegian had competed squarely on concept and price but found itself out-featured by the Stello and arguably outclassed on cosmetics too. The Ai500's bass power—not flab or undue girth but raw power—had pulled decidedly ahead to make for the more grounded and full-bodied performance. In that review's conclusion, I'd referred to April Music's voicing as perhaps more American in spirit whence it distinguished itself from the cooler Nordic vibe of the leaner Hegel.

But first, some housekeeping. Bypass allows you to run a dedicated preamp for hifi or a pre/pro for home cinema or both. Perhaps confounding at first—no, the remote didn't mysteriously get stuck—this also defeats all other input options unless one first clicks 'bypass' again to get out of its mode. Thus there's no accidental loss of sound during black-out video night when someone accidentally presses a button. Very smart.



Because there's only one input for the whole digital group, pressing that button repeatedly—by remote or on the main chassis—shuttles through the options of coax, optical, PC (USB) and iPod. The latter is peculiar since the iPod also has its separate input command. Either way selects the same input which is self-authenticating. Select it with no iPod connected and the display will reprimand you promptly: "No iPod". There's no power mains on the back and the frontal standby switch can be triggered by remote.


Like April Music's own Aura Groove, the Ai500 contains Apple recognition software to transfer file meta data from an iPod to its own display. Then the amp's nine iPod-specific controls on the remote (menu, enter, repeat, random, up/down, left/right and play/pause) also do the finger walking. This simultaneously defeats all the iPod's own controls including volume. The iPod's display simply shows the orange sun with the super-imposed Apple logo for signal lock, below it artist and track name in an endless exchange. The Ai500's display meanwhile turns into a ticker tape which displays the iPod's usual data. All the iPod's functionality is retained from the April Music remote and only scrolling one item at a time—the display is limited to one line—is rather less convenient than the iPod's snazzy scroll wheel through lengthy lists.

Enabling this interface relies on the included 30-pin-to-twin-RCA+USB-charger cable. As I found out the hard way, this does not work with Apple's own iDock. If you want to use that, you will only get iPod sound if the RCA connectors of April's cable tap into a standard line-level input (the USB charger lead of course remains in its socket and charges even when the Ai500 is in standby). For an instant handshake between iPod and the 500's dedicated iPod input plus transfer of all functionality to the April remote, you need to either connect the cable's 30-pin connector directly to the iPod; or use April Music's own iDock if you want the iPod to stand up. The 500's infrared eye now becomes the access point from which you control your iPod. It's a very slick bit of integration.

The amp runs quite warm so give it breathing room to not stress the internal parts. Even the chunky master control warms up and ditto the remote should it be left on the amp. This gorgeously machined wand sports only a round recess with slanted edge for its IR eye. This makes it more directional than my Esoteric remotes which use an ovoid for broader off-axis response. In the photo below, I had to aim the remote down and directly at the narrow display to trigger commands. Firing straight out from the seat went too high and missed. Even at that distance, the display remained very legible. Clearly someone with hands-on consumer experience had sat down with engineering to insure happiness on the interface front. It's a slam dunk for all but headfiers. Those are left out but April Music has them covered with a dedicated 100-Series headphone amp. Extrapolating from where various volume controls tend to sit in my system, the Ai500's taper is nicely shallow. It does not suffer premature gain and comes on nice and slow.
On the PC front, the USB input performance is a stand-in for Kevin Halverson's award-winning Streamer+ under the High Resolution Technologies brand. In that review, the overachieving Streamer had ruled victorious against the USB implementations of April Music's own Aura Note Premier and Stello DA100 Signature yet was matched by (but subtly different from) the 24-bit Sabre DAC in the Peachtree Audio Nova and indistinguishable from the Ai500.



The upshot was that the HRT box—and the Ai500 by implication—produce high image density, superb dynamics and rich tone colors to belong to the organic and grounded school of D/A conversion rather than major on highly airy, flighty, lit-up, 'fast' but also lean. In short, the USB socket on this integrated amplifier isn't after-thought convenience to sell to the MP3 nation. It's a serious hifi item that won't be readily outperformed by affordable external USB converters.
Inserting Bel Canto's PRe3 into the bypass inputs vis-à-vis April Music's own implementation of chip-based volume and active preamplification only spent money. The PRe3 bought no sonic advantages. To better the Ai500's integral line stage in timbre richness and three-dimensional sculpting took ModWright's two-box DM36.5 or Esoteric's C-03 set to 12dB of gain. Those machines are close to or exactly $10,000. While something less ambitious might have sufficed to best the Ai500, the PRe3's $1,695 did not. If basic math applies $299 for the Streamer+ and adds the Bel Canto preamp, we only have $1,500 left to spend on the Ai500's 150/300wpc power amplifier stage before we exceed its total asking price. Even in class D, we'd be hard pressed to scare up equivalents. This machine is packed for high value; with designer looks.
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