I have just completed a project on one of the BEST and possibly the BIGGEST headphone amplifier on the Planet. It is huge (600mm wide x 300mm depth) and weight around 70 lbs.

It was tailor made for a young guy who has the rare passion on the sound of vacuum tubes. I had built a couple of headphone amplifier for him using different types of direct heat triode tubes, and this is the final and ultimate construction of the series.

Tamura ISO transformers are employed for the construction to ensure un-surpass sound quality. We follow the golden rule – SIMPLE IS THE BEST.  Top grade iron plus best quality parts, simple and straight forward circuit design.

Here we use Western Electric 275A as the output tube. Compare to WE 300B, it is not well known, but considered by some audiophiles to be better or at least as good as the big brother. The useful output power of this tube is merely 4 watt, but it is already more than we need. The miniature western electric 417A is the driver tube. It will be coupled to the 275A through a interstage transformer. The design is extremely simple and effective as there is no capacitor in the signal path, and therefore no colouration or delay of any sort. The input is connected direct to the CD player or any signal source, and the level controlled by a high quality volume pot.

I am not going into detail of the construction and choice of parts etc. You may have other design and preference on parts. Hope you enjoy.