FX Audio D802C - Unboxing and Setup

I've been using a cheap amplifier from Jaycar ( http://www.jaycar.com.au/Sight-%26-Sound---Home/Home-Amplifiers-%26-Accessories/Modular-Amplifiers/Low-Cost-Mains-Powered-Stereo-Amplifier/p/AA0472 ) on my work PC for about 10 years now, and while it worked it's never sounded that great and has a fair bit of background hum.

Looking online for a replacement, I spotted the D802C on AliExpress: http://www.aliexpress.com/item/FEIXIANG-FX-AUDIO-pure-digital-amplifier-D802C-remote-USB-optical-coaxial-Bluetooth-AUX-input-80W-2/32428321269.html

Not just an amplifier, it's also a USB DAC and a Bluetooth receiver, so it should be able to talk to anything I get in the foreseeable future.

I took the plunge and ordered one.  A couple of weeks later the postman brought this plain-looking box to the door:

I couldn't find much English-language info about this device online, so I thought I'd do a quick write-up on setting it up.

Inside, you get a USB A-to-B cable:

a tiny remote control (with no battery so I haven't tried using it yet):

and this fairly large power brick:

5 amps at 32 volts should make 160 watts, so the claimed 80 watts per channel may not be as unlikely as I suspected.

The included power cord has a European 2-pin plug, but you should have a figure-8 cord sitting in a drawer somewhere anyway:

An absolute bevy of ports on the back:

From left-to-right you have RCA analogue inputs, the RF fitting for the included Bluetooth antenna, optical & coax SPDIF, USB input and speaker connectors with screw-down binding posts.

After hooking up the speakers and power cable, I plugged in the USB and it was picked up and installed automatically by Windows 10:

I set the new device to default output:

The "Advanced" tab lets you select the output sample rate, up to 192kHz in 16-bit or 96kHz in 24-bit:

The display on the front confirms the new sample rate:

I don't know if it's actually putting out 160 watts, but it definitely gets loud!  My little bookshelf speakers were making more noise than I thought they were capable of, without any distortion.

The default bass setting (+14) is too high, but otherwise it works perfectly out of the box.  Bluetooth paired with my phone with no issues.  I'd definitely recommend this for anyone who wants to get better sound from their PC than the usual powered speaker sets.

A Robot of One's Own

When the post-Christmas sales came around, I didn't want socks, I wanted an Arduino kit!

The Arduino is a tiny programmable computer, with connections for motors, sensors and networking, that's taking the electronics hobby world by storm, with new projects showing up every day, so I thought I'd have a go.

The Arduino board (left) is powered by a USB plug, in this case a phone charger, and is able to directly drive servo motors, making it ideal for small robotics projects.  The prototype board (right) lets you set up additional circuits, in this case a button to reset the position of the motors.

 
I built a simple robot arm out of Lego, with servos for the shoulder and elbow joints.

The servos have removable drive wheels, which have been glued to Lego pulley wheels for a strong but adjustable connection.

Every time the button is pressed, the arm randomly moves to a new position.  Not exactly "Number 5 is alive", but it's still pretty fun to watch it swinging around.  Look at it go!