[Amps] Parasitics & Filament Sag

[Tom W8JI]

> At one time, Emtron offered one of their early amps with 
> Nichrome
> suppressors.  I do not know if they found some rational 
> reason for changing
> More plausibly, they simply did not want to get "caught 
> up" in the
> nonsensical debates.
>
> If you're a manufacturer, would you really want to be 
> spending all your time
> on the phone defending your use of Nichrome as a result of 
> all the
> destructive discussions when you've got a business to run?

Actually Paul Hrivnak of Vectronics, when he was convinced 
the glass in Chinese 3-500's was melting from parasitics, 
included a nichrome hairpin in his single 3-500Z amp.

The amp kept melting holes in the glass of the tubes just 
the same as it did without the nichrome.
So Emtron wasn't the first.

We actually looked at nichrome about 20 years ago at 
Ameritron and even tested some amps set up that way. We 
found no difference at all except a decrease of ten meter 
efficiency.

Nichrome suppressors don't bother me one way or another so 
long as they don't cause a problem, although I'd probably 
never use one myself. The only reason I wouldn't use one is 
the hairpins actually measure to have more VHF Q than the 
conventional suppressors when in the circuit. Once you use 
multiple turns instead of a hairpin, you can make a 
conventional suppressor that has more effect at VHF and less 
effect at HF. Why hurt 10 or 15 meters when it isn't 
necessary?

The only harmful effects out of all of this is the setback 
in people actually understanding what causes problems, and 
harmful suggestions like installing resistor grid fuses and 
the bad advice telling people to remove electronic 
protection systems. Bad advice like that is a major problem.

73 Tom