At 05:04 PM 4/17/97 EDT, you wrote:
>Adding the filament winding to the plate xfmr is not considered good
>practice...except when viewed by bean counters.
I have no control in this case over "good practice" This is only the tip
of the iceberg! This amp is full of "bad practice". It is an Alpha 77SX.
My friend Vince and I have been working with these amps for over a year,
and they now have the proper components that should have been there in
the first place. I now feel that there are at least 2 77SX's on the planet
now that are as good and reliable a table-top amp. (dollars/watt)
that there
is!
> The typical 6-12% sag atkey down, etc is not going to make the tubes happy
.....unless they are 811's, 813's or some other forgiving driver level tube.
It MAY suffice in SSB service where the voltage change is too rapid to be
really
>effective...it averages out at some minus value from max.
Luckily, I have no sag here...less than 1 volt on the primary side and
none on the permanent filament voltmeter I installed outboard.
Sorry I confused the issue a bit by not naming the amp in question.
Since the 8877 is an external anode tube, no cool-down is required
by Eimac, but again, as in the inrush, common sense tells me to leave
the amp in standby a while until my remote digital thermometer indicates
a plenum temperature near room ambient before "throwing the big switch!"
(Personal note...I hope your XYL is doing FB!)
(((73)))
Phil, K5PC
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|