What is a Fetron

From tremolu–(at)–ol.com Fri Mar 31 23:25:14 CST 1995
From: tremolu–(at)–ol.com (Tremolux)
Newsgroups: alt.guitar.amps
Subject: Re: Fetron? (was Black vs. Silverface?)
Date: 31 Mar 1995 19:10:59 -0500
Sender: roo–(at)–ewsbf02.news.aol.com
Reply-To: tremolu–(at)–ol.com (Tremolux)

George, a “Fetron” was a device originally made by Teledyne Semiconductor
back in the 70s. It’s basically high-voltage FETs in a 9-pin minature
that fits into a 9 pin tube socket. The pinout was such that they’d work
in a 12AX7 type application. No, these are not the more modern “hexfet”
type of high voltage MOSFETs. I believe they were depletion-mode JFETs.
they couldn’t take as much voltage as a 12AX7. I believe they, since
they’re FETS and have more of a pentode type transfer characteristic,
provide more gain and less noise than a tube.

I actually have a couple of them (somewhere, if I haven’t lost them or
tossed them out) that I tried in one of my amps way back when. I found
the tone to be kind of harsh.

regards.