**SOLD** Pair of fully restored ADCOM GFA-565 Monoblock amplifiers $2600


Hi everyone! I don’t often have amps for sale; I am too busy with customer refurbs, and my meticulous nature isn’t conducive to high production throughput. :^/

But I had four GFA-565’s lying around, dead… Casualties of the great GFA-565 capacitor plague… not making any music, and just taking up space—a considerable amount of space—these things are massive!

So I gathered up the nicest-looking parts from the four amps, and built two beautiful amplifiers. The goal was better-than-new reliability, so of course they get entirely new GFA-565 Input Boards, loaded with higher-spec’d components than original.

Hoppe's Brain GFA-565 Input Board
GFA-565 input board
Fully restored GFA-565

In the interest of longevity, I have also replaced the main power supply filter capacitors. (I want these amps to last at least 30 years.) I selected Kemet ALS series capacitors for their low ESR, high frequency performance, and extremely high endurance rating of 12,000 hours. The originals are typical 2000-3000 hour caps, and yet I have never seen a bad one in a GFA-565. These should last virtually forever.

KEMET ALS Series caps. Also shown, an earth-loop breaker board that buffers the amp from ground loop noise.

All components that are reliability concerns have been replaced. As mentioned, the goal is a product life of 30 years or more. Electronically, the only remaining original components are:

  • Power transformer
  • Output transistors
  • Power relay and some parts on the soft-start board

Cosmetically, they are gorgeous amplifiers, but not perfect! If they were perfect, they would be $3000 instead of $2600. There are some of the usual signs of use, tiny nicks or marks. Please examine the pictures closely, they are very high resolution, and I took them outside in bright, diffuse light, which shows everything in greatest contrast. In a normally lit room, it is hard to see any imperfections in these amps, and they are beautiful beasts indeed.

Of course they exceed factory spec. 335W into 8 ohms, 586W into 4 ohms, and 937W into 2 ohms at less than 0.1% THD!
Each amp has been thoroughly stress-tested, and their performance characterized. Download their performance reports here…

Hoppe’s Brain Performance Report, Chris Hoppe, GFA-565 #0192154875

Hoppe’s Brain Performance Report, Chris Hoppe, GFA-565 #019215480

Here are detailed, high-resolution photos of GFA-565 #0192154875

…and GFA-565 #019215480

And some more photos documenting the build process.

Leave a Reply