I had two 5W chip amps (TDA1905) in my collection for many years but did not need just another low wattage power amp to drive speakers. The end result is a headphone amp. With the chips capable of driving eight ohm speakers to 5W driving 32 ohm head phones to just part of a watt should be easy. The manufacture of the chips claim 0.1% THD at 3W. That means the distortion levels into phones will be very low. And plenty of good drive power.
Using a similar enclosure I have used many times I hoped the amp would work with batteries but it drew too match current. Batteries were out. I have a few DC wall warts and a 12VDC 880mA unit was perfect for the job. I added another 1500uf of filtering in the amp some snubbing caps to keep noise low. Noise is less than 1uV. A mix of carbon and metal film Rs used throughout.
The headphone amp is dead quiet, sounds distortion free on both 250and 32ohm HPs and is clear and very detailed. The amp was constructed on a piece of vero-brd and solid Cat 5 wire used for hookup. And because I had a well preserved antique bakerlight knob on hand this dressed the front. Apart from a little too much gain the amp works perfectly and I have enjoyed many hours of music driven by it. A good outcome.
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