Introduction

It was about time my amp from the seventies era got upgraded. Over time the sound has become muffled, especially the higher frequencies. What better way to go then the new class D amplification technology. The main advantages are the reduction in weight, space and power consumption. It's also a plus that audiophiles consider it up par with high end audio equipment, and this for just a fraction of the cost of Hi-Fi equipment.

 

 

I considered to construct the AMP6 kit from 41Hz Audio because of all the raving reviews. I went however with the 2*100 watt @ 4ohm TK2050 Class-D Audio Amplifier Board from Sure Electronics after reading this thread on the DIY Audio forum. The board is pre built (no need for soldering) and retails for a meagre 27€ (45US$).  This is actually a class T amplifier, but that's just a trademark of Tripath - the chip producer - for this class d amp. It is an implementation of Class D amplifiers, but improves the control scheme to create more efficient and higher quality audio amplification. One of those chips, the TA2020, was named one of the twenty-five chips that 'shook the world' by the IEEE Spectrum magazine. I'll show you how i made it shake my speakers.

 

Unpacking

 

After some weeks of patience (it ships from China) the package arrived at my doorstep. First impression is that it's unbelievable small, well built and comes with nice accessories (mini stereo jack to cinch cable, extra fan, speaker cable plugs, mounting screws,...). It measures 12x10cm (4.7x3.9inch)

 

 

Here are some promising specifications:

 

Setup

So what i wanted is to be able to choose between two inputs using a channel select knob and have one on/off switch and a volume control. All this in a minimum amount of space and preferably something not bad to the eye.

 

 

I came across this sleek looking brushed aluminium box that would be perfect to act as my next amplifier.

 

 

Time to get the power drill and make some holes in that box. Two stereo inputs for my vinyl record player and one for my audio out of my computer. Next to them are the four speaker connectors.

 

 

From left to right you can see at the front the power switch, the stereo channel selector knob and the stereo potentiometer for volume control. I used an old Dell laptop switch mode power supply from a laptop. It can supply 19.5V and around 3 A, so that makes 60W. Well below the rated 100 W per channel of the board, but trust me, this is already loud enough. Especially when you use speakers with a high sensitivity.

 

 

Hooking up mains voltage to the power supply, with an salvaged old school switch in between so when it's turned off, even the power supply won't consume any power. I chose not to drill holes for better airflow because of aesthetic reasons and the fact that the board shuts itself off when the chips get too hot. Even after hours of operation, the exterior only feels lukewarm.

 

 

It's a close fit with the amplifier board on top. I also measured for short circuits, found none, put the lid on and ... we're ready to play some music. It's sounds so much better then my old amplifier. Better stereo separation and highs. It takes up less space on my desk, looks good and sounds good.

 

 

Lots of people upgrade the board by replacing the input caps or swap the stock inductors for toroids. This reportedly leads to even better acoustic reproduction, but i'm satisfied as it is. The biggest step up in terms of quality would be new speakers, as they have become the weakest link in my setup.