Chip-based class D

IC-based amplifiers do not exactly have a perfect reputation among hi-fi enthusiasts and class D chips are pretty much considered the bottom rung of the ladder. Most of them are mainly intended for mass-market products such as cheap receivers, box systems and flat panel TVs which are not exactly the last word in hi-fi and sound quality.

However, just because something is intended for mass-market products does not necessarily mean there isn’t quality to be found – there is usually some solid engineering behind these chips and if you lift the common restrictions of their normal applications (primarily board space and cost) then it is normally also possible to lift the performance significantly as well.

The Tripath family of chips (TA2020, TA2022, TP2050 etc.) are very good examples of this but now there are some new contenders as well. One of them is the TPA3116 from TI which has been getting good press over at diyaudio lately. This chip can be connected in both stereo and mono-mode and although the 100W power rating is a bit optimistic (at least if you still want music out of it and not just noise) there should be enough power on tap for normal domestic use.

I bought one of the cheap ebay-boards shown below as a test and also as a preamble for a more custom-built design of my own. Now, connecting a 12 EUR amp PCB based on a chip (and a class-D chip at that) to a 4000 EUR pair of speakers may seem heresy to some – and it probably is – but hey, you have to try 😉 I have not listened extensively to this board yet but initial impression is that the sound quality is actually quite good – and worth building on.

I am not far with my own PCB layout yet, but as I have a specific design concept in mind (which I will not reveal just yet 😉 ) I have already decided on a mono-block design and a max. board size of around 85×45 mm, so let’s see where it goes from there 😀



2 Responses to Chip-based class D

  1. Christopher Tan says:

    Out of curiosity, which EUR4000 speakers do you have? Knowing their impedance response on top of your comments would give readers a good idea of the performance of your amps…

    • theslowdiyer says:

      Hi Christopher,

      Good point. The speakers are Sonus Faber Cremona Auditor Ms, which are 4 ohm nominal impedance. I can’t find any measurements right now that show more detailed impedance/phase plots though, but I would think 4 ohm nominal does mean that the impedance dips down where a BTL amplifier might normally struggle. To be fair, my room is quite small so in absolute terms the power requirements are of course limited.


      PS: I recently upgraded to the Sonus Fabers, that’s posted here 🙂

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