I recently upgraded my desktop audio, for about the last fifteen years I used a 5.1 setup with a Logitech Z-5500 which have been OK. Nowadays I do more listening to music than anything else where stereo is more important than surround, not to mention the reclaimed desk real estate. I have a set of Sony bookshelf speakers laying around in storage so I went looking for a desktop amp. My requirements were an optical input with USB or analog inputs for secondary devices. Bluetooth wasn't a requirement as I can use PulseAudio on Linux to turn my desktop or laptop into a Bluetooth receiver but it would have been nice to have built in. I'm also a stickler for physical buttons and switches for switching inputs.

The Micca OriGain AD250 was still available from the usual online places even after stocks of other amps dried up due to COVID related importation problems. My other options were a couple of models of SMSL amps but I honestly like the looks of the Micca better. It's 50W on each channel which is more than enough for a desktop setup and has very simple forward facing controls.

My desktop machines have had optical out for years and I always use it. It's a nice way to bypass the onboard sound card that is usually mediocre at best and may have proprietary features or codecs that do not work fully in Linux. Optical is becoming far less common on laptops though so I wanted something with wither USB or analog in for times when I need it. Plus I still have an iPod or two laying around.

The AD250 is a compact and good looking box. I like having a physical volume control and the switches for changing inputs are nice and great to use. The power brick is a bit large and you'll want to relocated it off the desk.

Overall it sounds good and the output is well suited for a desktop type scenario. I wouldn't expect this to fill a large room.

The major downside has been the popping when using the optical input. It's like a power on pop and I thought it had to do with the power saving functionality on modern motherboards powering down the LED on the optical output. It's pretty easy to disable this feature in Linux:

/etc/modprobe.d/snd_hda_intel.conf
options snd_hda_intel power_save=0 power_save_controller=N

That should handle it on most onboard sound cards. It still happens less frequently and it may be either a power supply issue on the Micca or the circuit design around the amp. The fact that it doesn't do it on the analog input makes me think it's the Micca's power supply or perhaps the amp lacks a delay circuit. There's a slight chance it's in my Sony SS-B1000 speakers as they are 8 Ohm and that's right at the upper end of what the AD250 will drive. I've tried numerous optical cables and no dice, still pops. I’ve noticed it some one the USB input as well, just not as bad. Unless I can get the popping solved that may end up being a deal breaker for my use. Maybe a revision two of this amp will fix the optical port. I've read some comments from elsewhere on the internet that the optical input noise is not isolated to just my amp so it seems to be either a power supply issue, filter issue or some other design problem with the AD250.

It’s most annoying when you’re scrolling through a web page with many auto playing media sources, for whatever reason even if you have the audio muted each video clip that starts up causes the amp to wake up and pop

Overall I like the look, feel, feature set and user interface of the amp but for whats a $100 desktop amplifier I find the popping to be annoying. From what I came across in some internet searches the popping is not a unique problem to my copy of the amp either so there seems to be some quality control issue with these or some engineering or component issue. I do use a splitter on my desktop's optical output as I also send it out to an OriGen G2 for my headphones and neither of these devices seem to like the active splitter I have. Once the machine powers on they will just blast static at you if the optical input is still selected. I switched to a passive splitter and they behave much better. For now I plan on hanging on to the AD250 and seeing if I can figure out what the deal is with the popping. I have a 2015 MacBook Pro with an optical output as well that I may drag out of the pile to see if it pops with that machine. Could still be some driver or power save feature on my desktop causing it. The old Logitech system didn't have these problems with either machine.

For now I can say if you're using the USB input or the analog input this is a great little desktop amp with an awesome user interface. Just flip the switch to your input and turn the knob on for volume. No remote, no digital display to break just simple, classic and solid which suites my tastes quite well. It drives reasonably sized bookshelf or desktop speakers just fine and sounds very detailed I think. If you're a basshead it's probably not the amp for you. The optical input is still suspect though in my opinion but chances are most people aren't using those in 2020 so that may not be a deal breaker for you. Since I'm using the USB input on my docked laptop and the optical on my desktop I really need both digital inputs though.