I had a request from a Kiwi friend to make him a very compact and light headphone amp for his super expensive in ear buds and noise cancelling BOSE headphones. He travels regularly back to New Zealand to visit family and loves his music. I have made many headphone amps both portable and home...

A Kiwi friend of mine spends a lot of time on a plane. He has some expensive ear buds but found the plane's system really didn't drive them well. He asked me to make a small and light HP amp and this is the result. The enclosure is two tone ABS. I have lined it with bitumanised heavy Al foil and...

Oatley Electronics Australia, who is famous for the portable triode headphone (HP) amp, the K272C (latest iteration), has been working hard to produce a truly new and revolutionary home based HP amp. This time they are going out on a limb and have designed a unique and powerful output stage. It...

I was given these prototype cct. brds. (populated) some years back but only recently have I started to listen to them. There was a K311 and now a K311B and I think there maybe a "C". I have the schematic but at this point will not publish it. The amp is by Oatley Electronics. It uses two 2SK170...

This is a preamp\headphone driver using a single 2N3055. An electronic friend of mine said that many times large power transistor are quieter than smaller transistors due to their large base. I took his advice and made this emitter follower preamp\headphone amp. You lose about 10% of the signal...