>
>
>-----Original Message-----
>From: amps-admin@contesting.com [mailto:amps-admin@contesting.com]On
>Behalf Of 2
>Sent: 05 August 2002 00:17
>To: Phil Clements; dhearn@ix.netcom.com; Bob; AMPS
>Subject: Re: [Amps] ALPHA 77
>
>
>
>
>>> Why would one need to tune for grid-current ? Minimal grid current does
>>> not give a correct tune. Maximal grid-current does not give a correct
>>> tune. A correct tune is max out with the drive needed to produce 1A of
>>> anode current per 8877 -- which coincidentally results in c. 100mA
>>> grid-current per grid, which could be seen on a 0-500 scale. However,
>>> there is no need to measure grid-current on a cathode-driven amp.
>>> Grid-driven, yes.
>>
>>When I tune an 8877 amp, I tune everything for maximum power out.
>>I then tweak the PA loading cap slightly to give a needle-width decrease
>>on the wattmeter. I need to see the grid current at this time to make sure
>>it goes down and not up when making this adjustment. This slight reduction
>>in suds makes a nice increase in clean.
>
>>>True, Phil, but the 8877 is so clean that there are no transceivers even
>>>in the same league.
>
>Ain't that the truth and ain't that a disgrace!
>
Good point, Conrad. All it would take to make a solid-state final unit
cleaner is some neg. feedback R in the emitter or source leads. This
would be easy to do with 50v transistors.
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
|