note -- Quote level marks corrected.
On Aug 7, 2005, at 3:25 PM, k7fm wrote:
> Rich said:
>
>> "In all other HF 8877 amplifiers they are there. Was Dick Ehrhorn
>> and every other 8877 amp mfg out of line for using a parasitic
>> suppressor?"
>
> Rich, this is an interesting observation. In the past, you have
> criticized almost every manufacturer of 8877 amplifiers because their
> parasitic suppression was not your standards.
In order to reduce VHF gain, parasitic suppressors need to have a
low-Q. In your opinion, do Ag and Cu contribute to a low-Q?
> So, if these manufacturers do not know what they are doing, why should
> they be the standard by which others should be measured.
Even a medium-Q parasitic suppressor is better than no suppressor
whatsoever.
>
> There are many commecial amplifiers which do not use parasitic
> suppressors.
Can you name a commercial HF 8877 amplifier besides the AL-1500 that
does not use a VHF suppressor?
> Old tubes like 811s need them, because of internal construction. But,
> the 8877 is a modern tube similar to many of the high power tubes.
So Dick Ehrhorn made a mistake in the Alpha 77 by using a VHF
suppressor?
> Many high power amplifiers used in commercial services do not use
> parasitic suppressors.
Surely, but they are likely VHF or UHF amplifiers, not HF.
> In fact, using one may be an admission of either an older tube or a
> dated design.
The only tube that I have seen that is unconditionally stable in HF
service with or without a VHF suppressor is the 813
>
> Colin K7FM
>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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