[Simon] wrote in to tell us about a headphone tube amp that he just built. It is based on schematics at diyaudioprojects.com that were actually featured on Hackaday in the past. [Simon’s ...

It would be interesting to subject it as a headphone amplifier to a series of audio tests to evaluate the effect of a mains transformer over a dedicated audio one.

I love high-spec hardware, but sadly don't have the budget to support a high-end hi-fi habit. So, products such as the Astell&Kern ACRO CA1000T desktop headphone amp are usually well beyond my means.