A 110-watt at 8Ω Audio Power Amplifier based on "The Blameless Amplifier" design.

Project 61 Rev3 is based on a well-known audio power amplifier design, the Blameless Amplifier by Douglas Self. The design emphasizes heavily in reducing distortions to the lowest possible level.

The claimed THD figure comes close in comparison to the power amp input-stage LME49811 chip specifications. The prototype achieved a THD of 0.00072% and the SNR is 91.4 as measured by the QA400 audio analyzer. The measured power output of the prototype is about 110 watts into an 8Ω load with ±50VDC power supply rails.

Nevertheless, by using designers’ techniques the diminishing THD figure is likely achievable. Details of the circuit description of the amplifier design can be found in Douglas Self’s the “Audio Power Amplifier Design Handbook”.

How does Project 61 perform in the listening test? Listening to CDs of different genres, the experience was very impressive that you can hear excellent musical accuracy.

The latest version of Project 61 is available by request at [email protected].