BLQE - "Baby" Leach w/ Quad-Comp EF Output Design


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BLQE is the "Baby" Leach power amp with a Bryston-style Quad-Complementary output stage wired for unity gain.

  • fully symmetrical
  • Quad-Complementary output stage
  • buffered VAS
  • all-modern BJTs
  • 18 transistors
  • separate supply for front-end, or use HF-QS
  • board size: 3.8x3.8" 97x97mm

BLQE combines a traditional fully symmetric front end with Bryston's Quad-Complementary output stage wired for unity gain. The design is targeted at modest power levels of 20-60W, but can be used up to 160W. The circuit has on-board fusing for the output stage, along with local filtering. The front-end has its own supply connection to facilitate using "boosted" supplies or extra-filtered rails via HF-QS.

The free version of this design, BLQE FREE (450 KB), includes enough info for the hobbyist to make his or her own printed circuit boards, with the following PDFs:

  • schematic
  • parts overlay
  • top foil
  • bottom foil
  • bill of materials

Click HERE to download BLQE FREE.

BLQE COMPLETE (2,390 KB) includes the above info plus comprehensive notes about the circuit, component substitution, wiring, power supply details, along with Gerber and Excellon files to have a PCB house manufacture the boards. BLQE COMPLETE includes:

  • schematic
  • parts overlay
  • top foil
  • bottom foil
  • comprehensive notes - 18 pages
  • Gerber and Excellon files
  • PSU details
  • safety notes

Click "Add to Cart" above to purchase BLQE COMPLETE.

About London Power

London Power was founded in 1990 by Kevin O'Connor, after two decades of research into innovative audio amplification techniques. Kevin is an audio designer, author and speaker, known for his proprietary methodology called Power Scaling, and for his eleven books on audio subjects. Whether you seek amps, kits or information, you'll find useful answers here on not just the "how" but the "why" of audio amplifier design. Please enjoy the information on this site, and don't hesitate to contact us with questions.

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