Re: [Amps] Quad Tube 4cx800 hf amp

["Gary Schafer" <garyschafer@comcast.net>]

Here is something that is sometimes forgotten when in the quest for an amp
with "lots of head room".
If the amp is to be tuned and operated at its full power capability
everything works fine.

If you tune it up at its maximum capability but actually run it at a lower
level, your efficiency will be much lower.

Example: you tune the amp up for 4000 watts out but only operate it at the
1000 watt output level. If the amp has 60% efficiency at 4000 watts it will
only be operating at 30% efficiency at 1000 watts. Lots of wasted power in
plate dissipation.

Also intermod products do not greatly improve by operating at lower levels
either. They are pretty much fixed in a class B or AB amplifier. Actually
they may be a little worse at lower power levels than at higher power
levels.

Moral of the story: Build the amp for the capability you are going to use it
at. Not for what it could be operated at.

73
Gary  K4FMX


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