Raytheon JAN6418 sub-mini valve headphone amp

This shot shows the Oatley Electronics Kit in a small case to be constructed as a headphone amp/driver. The small cct. brd. is double sided, plated through, solder masked and screen printed. Construction is simple and this $AU27 kit makes an excellent first valve kit of any DIYer. See the other image for the completed headphone amp. The L4949 5V reg. chip lights the led for the first second it is on then only re-lights when the battery voltage falls below 6.8V. Nice touch. The reg chip supplies 5V to the filaments which are in series with a 270omh resister. The amp only draws 12mA. Two 9V lithium batteries power the unit. In the preamp version the PT2308 headphone driver chip was replaced with a Burr-Brown OPA2134. Excellent sound stage and rich bass. And it is a portable headphone amp!

There is more information available on the JAN6418 Valve (Tube) Headphone Amplifier Kit page.