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I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
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Ultra Low Distortion Class B Amplifier

Posted 9th April 2013 at 06:40 PM by alexcp
Updated 12th May 2013 at 03:49 PM by alexcp (Added better photos)

I built this one a while ago but could not find time to post.

This is a Class B power amplifier that follows the Ultra-LD Mk.3 amplifier design published by the Australian Silicon Chip magazine in 2011, which in turn draws heavily from the concept of a Blameless amplifier devised by Douglas Self. I used a different power supply and speaker protection, and changed the grounding scheme vs what was published.

The distortion at 1 kHz is below my measurement capabilities, and the amplifier does sound very nice, although it seems to give more sibilance than my Class A amplifiers.

The acid test I use is the dual CD "The Very Best of Placido Domingo" album published by EMI Classics. Many amplifiers I have heard cannot deal well with Domingo's tenor, esp. on louder and higher tones. Class A amps, particularly those using simple internal structure like the Zen series, perform well in this test. This amplifier seems to do better than any other Class B or AB that I have had a chance to hear, and is approaching Class A.
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Comments

  1. Old Comment
    very good! :cheers:
    permalink
    Posted 1st March 2014 at 12:46 AM by sjh327 sjh327 is offline
 

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