Last update: 25 october, 2009

A new class of amplifiers?

During 2007 I became aware of a new type of amplifier based upon one IC only. I read about these 'chipamps ' on internet forums but my final decision to try one came after the advice of Soundcheck. He told me that he sold his tube amplifier after hearing one at his home.  These tiny amps are often based on a Tripath IC's and are often called  "digital amps". This term is incorrect, there is no AD-DA conversion, it is a switching amplifier. An LC-filter is usually placed at the output to remove the high frequencies of the switching.

I decided to first test a copy so I looked around where to buy one. The cheapest and easiest to make seemed to be the 41Hz AMP6-Basic. The circuit board with all components is only 35 Euro so I ordered two. The advantage of the AMP6-Basic is that all parts are hole mounted, other version may have surface mount components that are much more difficult to handle and solder. I build both amplifiers in small housings
 

The smallest 2x20 Watt amplifier I ever made.

Test setup for the AMP6-Basic at my ceiling. Already here I found the sound of the TA2020 very convincing and after a short test I decided to keep them in my main system and to sell all my tube stuff.

The upgraded Audiodigit T-amp 2020 with air core inductors below the circuit board and Black Gate capacitors. The Siltech silver strips are directly soldered to the pins on the circuit board.

The Audiodigit Class T-Amp 2020 build into the housing of my tube amp together with its 12 volt battery and charger.

First full setup with TA2020. The volume control in the center of the amp is the Acoustic Dimension stepped attenuator. The filter for the bass can be analog (top right in the amplifier) or digital with the Behringer DCX2496.

 In januari 2009 I put in a newer version the TA2021B. This one is surface mount but the soldering was done in Berlin for a few euros extra. Its specifications seem only marginally better than the TA2020 but the sound is improved specially in the high frequencies: more natural and more detailed.

Notice that the volume control is removed, this is now done in the digital domain (see detailsDigitalAudio). The interlink to the Buffalo DAC consists of no more than the Mundorf Silver coupling capacitor. DAC and amp are now fed from the same battery.