Hi robertospeed,
The D03 was an amp that I was very interested in and was purchased at the same time as it was released.
Thank you for setting up the forum.
For me, who takes pride in being a pure audio enthusiast, I have always thought that a full digital amplifier like the D03 is a bad idea. However, since full digital amplifiers have recently been adopted in high-end products, I got the newly released AIYIMA D03 and tried using it. And I fell in love with this product, which has higher sound quality and power than I had imagined.
The first thing I felt when I heard the sound of the D03 was that it had the same sound quality and power as the A07 of the same AIYIMA that I praise. I realized the performance of the latest full digital amplifier.
The D03 isn't the perfect product, but I've come across a very good amp.
I will introduce my impressions while comparing this D03 with A07.
There is no pop noise associated with turning the power on and off, which I always care about most. There is no pop noise even if you unplug the AC adapter while playing. Like the A07, this is ideal for applications where the entire system is turned on and off with the master power switch.
I feel that the white noise when there is no sound is less than that of A07.
Since the volume is digitally controlled, the volume change is very smooth. There is no gang error, and the increase / decrease steps can be finely controlled from 0 to 99, making it easy to adjust at low volume at midnight. Adjusting the volume using the knobs may seem a little complicated due to the large number of steps. We recommend using the remote control for frequent operations.
The tone control has a very natural change in both treble and bass. I always use it for loudness. Pure audio enthusiasts hate tone control, but it's nice to have one. When I listened to A07 at a low volume at night, I was dissatisfied with the sound, but with D03, I can enjoy music comfortably using the tone control. However, this unit does not have a function to turn off the tone control.
The input can be smoothly switched between USB> OPT> COAX> BT> AUX and cyclically. There is no noise when switching, but sometimes there is a clicking noise when switching from COAX> BT. This point needs improvement.
The BT connection is displayed as D03 and can be easily connected. There is no PIN code to enter when connecting.
The operation can be done with the knobs and buttons on the main unit, but the remote control is more convenient.
Batteries for the remote control are not included, so prepare two AAA batteries separately.
The remote control was tested in the range of 60 degrees from a distance of about 3 m, but the response was good.
The heat generated by the main unit feels quite hot in a room with a room temperature of 28 degrees.
The AC adapter comes with a 32V/5A one. I feel a little heat here. I think this AC adapter is probably the same as the one that came with the A07.
The USB / OPT / COAX input rate supports all PCM 44.1kHz to 192kHz 16/24Bit. D03 does not support 88.2kHz and 176kHz on the way.
It's perfect. SMSL SA300 displays PCM 44.1kHz to 384kHz 16/24Bit, but I was disappointed that the middle part was actually thinned out.
The sound quality is important, but the sound quality is high enough for USB/OPT/COAX/BT, and there is no difference between them.
You can easily enjoy the sound quality of A07+E30 class.
However, the AUX input is not good. Compared to digital input, the sound quality is much more relaxed and quiet.
Also, the input sensitivity is somewhat lower than the digital input. It is good for applications such as listening to BGM.
Is this amplifier mainly for digital input and AUX is a bonus position? On the SMSL SA300, on the contrary, the RCA AUX input has high sound quality, but the USB sound is poor.
I listened to D03 at a loud volume that would make me complain from my neighbors, but I felt that there was plenty of power and it drove the speakers in a stable manner. It seems that the damping ability is also high. I got the impression that it had more power than A07.
As a point to be worried about D03
The brightness of the display display cannot be adjusted and the display cannot be turned off. The brightness of the blue display can be annoying when connected to a TV.
The white frame of the push button on the front panel and the feel when the push button is pressed feels cheap. I think this spoils the D03 value a bit.
I want you to improve the sound quality of the AUX input a little more. It's a little too bad.
However, you can easily enjoy high-quality sound by connecting to a PC or smartphone without a DAC, it has the same power as A07, there is no pop noise, and I think that D03 is a very satisfying and good product as a whole.
I think you should choose either one according to the purpose of use instead of choosing one.
If you enjoy DIY, A07 is the best, but if you want to enjoy the sound quality of A07 more easily, I think D03 is the best. It's good to enjoy both together like I do.