The search returned 4 articles:

  1. July 2015: Project: Ultra-LD Mk.4 200W RMS Power Amplifier: Preview by Nicholas Vinen, PCBs: SC 01107151, 7 shop items
  2. August 2015: Project: Ultra-LD Mk.4 200W RMS Power Amplifier, Pt.1 by Nicholas Vinen, PCBs: SC 01107151, 7 shop items
  3. September 2015: Project: Ultra-LD Mk.4 200W RMS Power Amplifier, Pt.2 by Nicholas Vinen, PCBs: SC 01107151, 7 shop items
  4. October 2015: Project: Ultra-LD Mk.4 Power Amplifier, Pt.3: 110W Version by Nicholas Vinen, PCBs: SC 01107151, 7 shop items