LM3886 Done Right Kit

LM3886 Done Right KitThe LM3886 Done Right extracts as much performance from the LM3886 chipamp as possible without using error correction and other tricks. It delivers 65 W into 4 at a higher performance level than specified in Texas Instruments' LM3886 data sheet! The stellar performance is achieved through proper decoupling, a well engineered PCB layout, and genuine quality parts. The LM3886DR circuit board is made in Canada and the parts are sourced from authorized

The LM3886 Done Right extracts as much performance from the LM3886 chipamp as possible without using error correction and other tricks. It delivers 65 W into 4 Ω at a higher performance level than specified in Texas Instruments' LM3886 data sheet! 

The stellar performance is achieved through proper decoupling, a well-engineered PCB layout, and genuine quality parts.

The LM3886DR circuit board is made in Canada and the parts are sourced from authorized distributors in North America. The Kit contains all the parts needed for the two amplifier modules in a stereo amp.

Technical Documentation

Data SheetDesign Documentation

• Features
• Circuit Topology

• The key features of the LM3886DR are summarized below.

  • 65 W into 4 Ω, 40 W into 8 Ω when used with the recommended ±30 V power supply.
  • Mono board allows for mono block construction. The Kit includes two LM3886DR circuit boards and the parts to populate them.
  • PCB layout is fully optimized for high signal integrity.
  • Elaborate use of copper planes and pours for the best audio quality possible from the LM3886 without error correction.
  • All components needed for good amplifier stability included in the circuit.
  • Input RFI/EMI filter prevents all pops and clicks from the switching of heavy loads as well as buzz from with cell phones, WiFi, and other RF interference sources.
  • Input ESD protection protects the amplifier from electrostatic discharge.
  • Click and pop free startup and powerdown.
  • Terminal blocks accepting up to 10 AWG (5 mm²) wires are used for the power supply and speaker connections.
    
  • Gold plated circuit board. Made in Canada and fully electrically tested by the manufacturer. 
    

  In addition to the parts provided with the Kit, you will also need some thermally conductive paste (Wakefield #120, Wakefield #126, Arctic Silver, et al.) and a heat sink for the LM3886.

  The LM3886DR needs to be powered by a power supply in the range of ±20 to ±30 V. I recommend a Power-86 with an Audio Grade Power Transformer. Many 24 V switching power supplies, such as the Mean Well LOP-series can be used as well.

  Curious about how to put this Kit together? Watch the build video below.

• The simplified schematic of the LM3886DR is shown below.

  The RFI/EMI filter prevents the annoying clicks and pops from the switching of heavy loads, such as refrigerators, electric furnaces, and the like. It also removes the interference caused by cell phones, WiFi routers, and such to allow for the best audio performance.

  The ESD protection protects the amplifier against the electrostatic discharge that occurs when a cable is plugged into the input of the amplifier. 

  Observant readers will recognize the noise gain compensation applied at the inputs of the LM3886. This compensation is necessary to avoid quasi-oscillation near clipping and is necessary to get the full rated output power from the LM3886. A series RC network is added in the feedback path to ensure a clean and fast transient response of the LM3886DR. A snubber or Zobel network (R+C) and Thiele network (L || R) are added on the output to ensure good amplifier stability even with a capacitive load.