Dave....your 3K-A numbers are the same as mine.
I bought it new in 77' and picked it up at the factory in WLA.
It still has the same tubes and still makes rated power.
I did put in a vacuum relay antenna changeover relay and an Agastat timer on
the blower in 1980 to keep the fan running for 10 minutes after the power is
shut off.
Great amp....I use it all the time.
73
David Harmon
K6XYZ
Sperry, OK
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of David Gow
Sent: Wednesday, June 15, 2016 5:30 PM
To: 'Joe' <nss@mwt.net>; 'Amps group' <amps@contesting.com>
Subject: Re: [Amps] Bring a SB-220 Back To Life.
Those tubes ae rated at 4000 volts absolute maximum according to Eimac data
sheets.. Most companies ran them at about 2800. Henry was an exception, my
Henry 3K-A uses a 4000 volt transformer with choke input and the loaded
voltage is about 3600 which is proper for choke input and Henry rated the
amp at 2000 watts OUTPUT. If you are putting 5600 volts on the plates
that is why you are getting so much output but it is way beyond the tube
ratings. Possible someone replace or rewound the plate transformer since
the manual says unloaded plate voltage should be 2500 volts or I hope you
were not running an amplifier jumpered for 120 on a 240 volt circuit which
would make the filaments bright indeed and also eventually make the
capacitors explode, probably. Good luck, I have had several SB-220s and
they are great amps.
Dave W7VM
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Joe
Sent: Monday, June 13, 2016 9:36 AM
To: Amps group
Subject: [Amps] Bring a SB-220 Back To Life.
I have an old SB-220, That when it was running, ran like what? Holy COW!
Long story.
Anyway, I desire to being it back to life. It was last on the air in 1993.
And has sat in storage places, and damp basements ever since.
As a primer to the home-brewing of these other Amps I plan on making. I want
to bring this girl back to life.
I will shortly be installing the 220 power in the shack, and even have ready
for it a 220 volt variac.
So, I have discussed this with some others, and got several different
theories on how I should proceed in bringing this back to life with the
least possible chance of any damage.
So what do all you pro's here say. step by step, what would you do if this
was your amp. And you wanted to bring it back to life after sitting since
1993.
Here is the story of how I came to own this amp, and it's,,, well,,
uniqueness?
http://www.qsl.net/nss/SB-220-Story.html
Joe WB9SBD
--
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
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