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Metallurge: Anyone laying eyes on April Music's value-priced components in the 500 Series can't fail to be impressed by their sleek metal work. Responsibility for the industrial design goes to MSD™ aka Metal Sound Design, an ambitious loudspeaker firm established in 1998 who work exclusively with metallic chassis and who have lent their design expertise to Silvaweld, Posnic and April Music.

April Music's newest, the $9.000 Eximus CD5 with its quartet of BB/TI PCM 1704 K chips in dual-diff class A with AKM4125 upsampler, OPA 627 I/V conversion, discrete FET output buffer and top Philips CD PRO2 sled, again sports signature MSD cues [below].

But so does the $3.000 CDA500. What's more, its comprehensive sockets of digital i/o ports—Toslink, coax and USB in; Toslink and coax out—and RCA/XLR analog outputs nearly duplicate the thrice-priced stable mate (the CD5 adds a second Toslink input and an XLR output).

Unlike the pricier Sino-Canadian Raysonic and French Metronome decks I reviewed recently, this Korean can thus work as stand-alone DAC for both legacy and PC audio sources. It also offers more connectivity options than the new €3.500 AMR CD-777 which carries USB/RCA inputs and one RCA output for digital.

In short, the Stello CDA500 would be called luscious if she were a woman. In hifi, we simply call her full-featured. Equal thoughtfulness extends to the superbly legible big-size red display; 5 display dim modes including off; switchable upsampling (96/192kHz) plus bypass from both remote and front; and repeat one/all by wand and fascia. The all-metal remote meanwhile duplicates the elongated oval profile of the player. Très chic!

Prior to any listening, the CDA500 mimics the Ai500 in 'super' status. Show reports on the CES 2010 noted surprise over how well the Ai500 had handled Magnepan's Model 20.1, a speaker known to be demanding on amplifiers. Might April Music have another heavy hitter with the CD+DAC=CDA deck?

It runs the Burr Brown/Texas Instruments PCM 2704 as a 48kHz USB receiver with a special ground-loop interruptor. There's an AKM 4125VF asynchronous sample rate converter for jitter reduction followed by a 24-bit/192kHz AKM 4117 processor followed by the flagship Cirrus Logic 24/192 CS4398 D/A converter chip. The latter sports differential outputs, minus 107dB of TDH+N and 120dB of dynamic range. This is followed by a 4th-order digital filter and analog output stage with a very high input-impedance JFET buffer.

Click here or on the photos for the complete pictorial coverage of Mr. Porter

There's also a Philips P89C51RC microprocessor for general housekeeping duties while the transport assembly is from Sanyo, the servo chip set from Toshiba.

The lower photo shows how the KD Motor-driven laser pickup assembly decouples from its standoffs via rubber grommets while the black CD tray with its finger grips hovers above it on its own hard-coupled stilts.

There are four Fairchild 278RO5 family output transistors and two voltage regulators. Two Indian Talema Amveco 25VA power transformers feed the digital and analog sections separately. A tucked-away 117/240 voltage selector allows convenient conversion. There are various Japanese Elna Silmic capacitors, with 8 x 1000uF/25V units in the power supply alone. There are multiple Samyoung caps, ultra-fast recovery Vishay diodes and 1% precision resistors on the single circuit board which runs the bare minimum of flying leads and ribbon cables.

As externals suggested, this is a very tidily executed machine also inside. Dimensions are 460 x 86 x 400mm, weight is 9.6kg. Delivery includes a generic power cord, a USB cable with integral ferrite clamps, the classy remote control and a basic owner's manual.

As a top loader, proper disc insertion relies on a puck. April Music's is sizeable, elegantly machined and finished in a gun-metal grey. Getting it centered takes some practice due to its large diameter. Then an optical trigger automates read-in of TOC as soon as the sliding door is closed even though the remote sports a back-up button called 'disc' which serves the same function. The default setting for upsampling is 'bypass', i.e. none. Smartly, the first push of the upsampling button (front panel or remote) merely display the current setting. If you want to change it, you press again to shuttle through the three options. Each time the sound will drop out for a second while the circuit adjusts.


As already was the case with the Ai500, the frontal standby control with its elegant white LED can be triggered by remote. The CDA500's wand covers all the usual programming features of time display, scan, random, A/B bracketing, then adds upsampling and input selection (CD or external sources). And like for the face plate, the Stello branding is engraved rather than silk screened.

The only perceptional blemish of this machine is the old Burr Brown USB receiver. It's been shown to suffer high jitter. More modern parts like TI's TAS1020B accept higher resolution input signal and allow reprogramming to asynchronous mode to not be slaved to the computer clock. (With PC audio, changes in sampling rate occur every millisecond. They are adapted to an average clock value which gave this scheme the name adaptive mode.)

Considering the year 2010 release of the CDA500, I was curious what had prompted Simon Lee's preference for the PCM 2704 and how he'd worked around its known limitations. And, what exactly were the differences between the Ai500's and CDA500's digital circuits: "The CDA500's digital signal path is PCM2704 or S/PDIF into the AK4117, then via I²S into the AK4125 ASRC into the CS4397 DAC. The Ai500 omits the upsampler and uses the AK4395 instead of the Cirrus Logic DAC. Neither machine needs traditional I/V conversion because both the CS4398 and AK4395 chips have voltage outputs. The jitter performance of the PCM2704 is reduced by the asynchronous sampling function of the ASRC chip. The recovered clock from the PCM2704/DIR chain is completely different than the separate master clock of the DAC. We also use an isolation pulse transformer as ground interrupter for the digital audio input stage."