POWER AMPLIFIER

Yes, this is a GainClone... Or, more precisely – probably the third iteration since the legendary LM3875. This legend began in 1999 and has largely been forgotten today. The original LM3875 is practically no longer found on the market. Audiophiles favor Class-A amplifiers, SPL enthusiasts are content with Class-D, and there’s been less and less talk about Class-AB. Since I have already embraced the advantages of Class-A in my tube preamplifier, it made sense to have a power amplifier that is as "clean" as possible in terms of sound. The first amplifier I ever built was based on an inverted LM3875 circuit. So my initial idea was to use some old microchips I had lying around and see how the symbiosis of Tubes and a GainClone worked in practice. The result completely met my needs and adhered to the “good enough for the money” principle.

Advantages of GainClones:

• Simple circuit design;
• Really good technical specifications;
• Due to standardized production, the microchips themselves hardly differ from one another in their parameters
  (with very little tolerance for deviation);
• Sufficient power for listening to music at home.

One drawback is that the LM3875 has long since ceased production. However, "Texas Instruments" has released several generations of its descendants. I still have a few LM3876 (the same as the LM3875 but with an integrated mute function), and T.I. still manufactures the LM2876 (a slightly weaker version of the LM3876) as well as the LM3886.

Today, my power amplifier looks like this:

• LM2876TF or LM3886 chips;
• Class-AB;
• RCA input (49 kΩ);
• Toroidal transformer;
• Stepped input signal attenuator;
• 2 x 30W or 2 x 40W real power.

Dimensions:

• Height: 8 cm.
• Width: 35 cm.
• Depth: 22 cm.