wrote:

"**One more trap for the uninitiated: NEVER crank up an audio amplifier
fitted with V-FET output devices on a variable auto-transformer.
Destruction will be assured under such a test. "

You mean class D I assume ?


** V-FETs were TO3 linear devices made and used by Sony and Yamaha in a number of hi-fi amplifers back in the mid 1970s. Common part numbers were 2SK82 and 2SJ28.

Then they suddenly stopped making them.

As a result, V-FETs and the few amps concerned are now rare and so have acquired a mythical status among the gullible.

BTW:

Do not confuse V-FETs with Hitachi's "Lateral Mosfets" that appeared later and were a huge success especially in high powered pro-audio amps.

Common numbers were 2SK135 & 2SJ50 or 2SK176 & 2SJ56.

Then they suddenly stopped in the late 1980s.

However, near identical TO3 MOSFETS are still made and carry numbers like BUZ901 and BUZ905.


.... Phil












Google " Sony V-FET " and learn more than you ever wanted to know.