Electronics with passion: amplifiers and power supplies, FET's and vacuum tubes..

Month: October 2011

BH delay schematics or let’s minimize relay contacts bouncing

For this article let's accept an axiom that warming up heaters well before raising B+ is a must for any good behaving thermionic valves based equipment.
Picture found on the Net. In case it impairs any copy-rights - please let me know so I can remove it.

HotFET Pre: J-FET audio preamplifier schematics

[Читать на русском]

At a first glance there's nothing difficult in building a unity-gain preamp: the well known and fairly simple source follower should do the job. However in my case it turned out to be quite an adventure. Why "HotFET" - please refer to this article.
HotFET-Pre (c) - prototyped in a "networking" case
The design is pretty simplistic. There were many calculations, tests and