Speaking of re-reading....
Thanks
73
Jim W7RY
On 3/25/2019 2:09 PM, Carl wrote:
I hate to break the news to you but I have a few decades more
experience building, using, and servicing amps than you can claim so
back off on the snotty comments. That includes a couple of commercial
ISM products.
Getting back to the 2 holer AL-1500, it will handle ~ 3dB over 1500W
and survive if only done for short periods such as in a pileup and a
bit of extra air. A stiff 240-250V line is a given as well as using a
better PS board if the HV exceeds the cap ratings. In normal use the
tubes are loafing.
The tuning networks are up to the users but are easily tweaked if
wanted as is an external transformer.
Carl
----- Original Message ----- From: "Jim" <jimw7ry@gmail.com>
To: <amps@contesting.com>
Sent: Sunday, March 24, 2019 8:40 PM
Subject: Re: [Amps] Replacing padder caps on an Alpha 77DX / SX
If you think that adding a second tube double the plate load
impedance....
then you don't understand how linear amplifiers work.
Now if you double the plate current, (1.8 amps, which a stock AL1500
wont do) then the plate load is half.
But the best you could hope for is 1.1 amps or perhaps a little bit
higher on CW or SSB... Then it would certaly increase.
Last time I checked, plate load is a function of plate voltage and
plate current. Nothing more... Nothing less.
Good luck getting 3600 to 4000 watts output from an AL1500.
73
Jim W7RY
On 3/23/2019 1:58 PM, Jim Thomson wrote:
From: "Carl" <km1h@jeremy.qozzy.com>
To: "Paul Christensen" <w9ac@arrl.net>, <amps@contesting.com>
Subject: Re: [Amps] Amps Digest, Vol 195, Issue 10--Replacing padder
caps on an Alpha 77DX/SX
<And also 2 holer AL-1500's which was as simple as using the AL-82 tube
<chassis and a filament transformer. W8JI pioneered that swap for
his own use.
<Never had a report of any failures.
<Carl
## Very slick ! Is the oem PI net retained ? The resulting
plate load Z with
a pair of 8877s would only be one half of a single tube. The 2
holer would require
double the tune and load C..and one half the UH on each band.
## Was an out board B+ supply used ?
Jim VE7RF
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