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[AMPS] Switches

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Subject: [AMPS] Switches
From: (Tom Rauch)
Date: Fri, 13 Oct 2000 08:30:19 -0400
> I wouldn't say that the screen supply in the 91/99B is well regulated
> (only zeners) so that amp doesn't necessarily show us the best IMD
> performance the 4CX800 is capable of.

Many amps have less regulation than that Ian!

My point is that by the time you build a good system that rivals GG 
triodes for IMD, it costs more money that the triode amp.

Unless you add negative feedback in the cathode of the tetrode and 
use a well-regulated supply, they aren't so clean.  
> Even so, I think it's being far too sweeping to imply that all tetrodes
> have worse IMD performance than (all) triodes. There are far too many
> other factors in the design and operation of an amplifier.

Of course. Some tetrodes are very clean, but then are some 
> There's no doubt that tetrode amps are much less "plug-and-play" than
> triodes. It's easier to get things wrong, either at the design stage or in
> operation. But if you do get everything right, a tetrode can give good IMD
> performance.

The key is "getting everything right". Many hams can't tune a GG 
triode properly, I'd hate to see what they sound like with the screen 
in current limiting!

> >you still haven't solved the bandswitch problem.
> >
> Which all tube amps share alike.

Exactly. That problem remains the same.

73, Tom W8JI

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