Oatley has continued to improve their headphone amppreamp with the release of the K272C. I had something to do with this progression consulting directly with Oatley. In fact there was a K272B between the K272A and the “C”. Here are two K272C headphone amps, assembled from the new kits which sell for $40 from Oatley.

The improvements over the original K272 are:

· 18V working

· Separate filament and B+ batteries

· Filament and B+ battery health LEDs

· OPA2134 driver chip


The kits are very easy to assemble with the excellent PCBs being screen printed and solder masked with through hole plated. The sound has improved with better bass response.

In this build I Al lined the ABS compact enclosures and used switched 6.5 stereo phone jacks. Only with both source and headphone plugs inserted and the press button switched “on” at the rear will power flow. Wire-wrap wire has been used in the signal path and the battery health LEDs have been brought out to the front of the enclosure. The sound appears to have better bass than previous models but the tubes will ring if struck.

Comments

• Stixx
• 4 June 2013 at 04:43AM
• The custom badge makes all the difference :)!

• mwhouston
• 28 January 2014 at 04:56AM
• Sorry late reply. Yes these HP amps sound like rubbish without the Decal. lol.