A CD player with integrated DAC and interesting features
The Aura Neo CD Player/DAC is a unit produced by April Music that combines in a single chassis a top-loading CD player and a versatile digital-to-analog converter. Among its features:
- USB, coaxial and TosLink input up to 24/96 (with upsampling function up to 192 kHz),
- Cirrus Logic CS4392 converter with AK4117 receiver and AK4125 ASRC,
- Balanced XLR and unbalanced RCA outputs,
- possibility to operate also as a digital transport.
The problem: burnt transformer and damaged mechanism
I was contacted by a customer who owned one of these players, with the power transformer defective. The original component was a small resin-potted toroidal, a particular format that has always been difficult in Italy: no local transformer manufacturer seems to have cores that small or machines suitable to wind them.
For this reason I could not accept a “remote” rewind without having the unit in hand. It was necessary to physically evaluate alternative solutions. The customer then shipped me the entire CD player… but here another problem came up…
Beware of the CD clamp “biscuit”!
The magnetic clamp that rests on the motor spindle (what I call here the “biscuit”) must never be left inserted during shipping. It is a heavy metal disk, and the spindle of the CD player motor is long and thin. In this case, with the shocks of the trip, the inertia of the clamp bent the motor spindle, detached the tape that held it in place and, wandering inside, caused further damage. Result: in addition to replacing the transformer, the entire CD player mechanism also had to be replaced…
Fortunately this part is easy to find and rather inexpensive. I always recommend shipping the unit with the clamp wrapped in bubble wrap and left outside the player.
The solution for the transformer
Once disassembled, I removed the faulty toroidal and, together with one of my suppliers, evaluated alternatives. Since the power required by the player is modest, the choice fell on a UI-core transformer, boxed and resin-potted, much easier to source and more robust.
I fixed it to the chassis with two screws, drilling only two new holes in the bottom of the player. Once reconnected, the unit powered up immediately without abnormal current draw: a sign that the fault was limited to the original transformer, clearly defective. It should be noted that very small toroidals sometimes fail even without particular overloads: an inherent weakness of the format.
Replacing the mechanism
The old mechanism with the bent spindle was removed and replaced with a new compatible unit. Once everything was reassembled, the player resumed working properly, both as a CD player and as an external DAC.
Technical note on the DAC via USB
I wanted to run a direct test on the internal DAC: Connected via USB to the lab PC (Linux), it was recognized as a standard USB Audio Class Device. However, while generating digital signals, I noticed that the DAC worked correctly only with streams at 44.1 kHz / 16 bit, with sampling rates at 96 or 192 kHz the software returned an error and no signal came out of the DAC output.
The datasheet claims support up to 192 kHz/24 bit, so it is possible that it was a temporary problem or a compatibility issue with the Linux system in use. Still, it remains an important note for those who want to pair it with streamers (all Linux-based) or Linux-based media servers (Raspberry Pi, Daphile, etc.).
Conclusions
This repair demonstrates two things:
- Never ship a CD player with the magnetic clamp inserted, because it risks destroying the mechanism;
- For very small toroidal transformers it is often better to replace them with more reliable alternatives, such as a classic resin-potted UI-core.
The Aura Neo, once restored, remains a pleasant and good-sounding unit, even if there seem to be some limitations on the USB DAC side. If any readers have had different results, especially with sampling rates higher than 44.1 kHz, feel free to share your experience in the comments: it will be useful for the whole community.