Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 11 Jul 2006 10:23:03 +0200 (CEST)
You may remember a couple of weeks ago, I asked for comments on the amplifier that was OK at 3.5MHz and went mad at 3.7MHz. At last, I'm at home for long enough to actually look at it. Someone sugges
Why? Q of one small part of a complex system doesn't determine anything by itself. If it did, we'd never be able to build a R/C oscillator circuit now would we? Many of these resistor swamped grid d
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 11 Jul 2006 13:48:29 +0200 (CEST)
determine anything by itself. If it did, we'd never be able to build a R/C oscillator circuit now would we?< But we have a case here where the Q of the whole grid circuit is much less than 1, i.e. it
Phase shift of the feedback is an issue in any oscillator. The point is things can oscillate with almost any Q if phase is correct and feedback level is high enough. The biggest worry with paper amp
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 11 Jul 2006 14:44:05 +0200 (CEST)
the problem frequency show?< I don't know, of course. And as the thing is now in the process of change, I'll never know what it was. Once the change process is complete, I will measure the reverse is
Talking about paper amplifiers........ One phenomenon I've observed is when the paper amp turns into metal and other bits, and how when the bits go into a box with a cover, the bits behave differentl
That's because the choke, at the lowest order series resonant point, acts like two back-to-back L networks with very high L and low C. Since the impedance step up and step down closely match, the th
Dear Tom, Thank you for your reply. What I ended up doing in the worst offender amp was to completely rewire the choke, twice, and then changed the cold end's bypass capacitance to another value. The