A single 3CX/3CPX800A7 will replace a pair of 8874's and is almost a plug in
swap.You will need a new filament transformer.
https://frank.pocnet.net/sheets/140/3/3CX800A7.pdf
Carl
----- Original Message -----
From: "Jeff Dorsey via Amps" <amps@contesting.com>
To: <LDighera@att.net>; <Amps@contesting.com>
Sent: Monday, October 15, 2018 7:19 PM
Subject: Re: [Amps] KPA1500 in QSK mode
Larry:
The 76a is not modified so it needs 8874s as far as I know. And I have not
succeeded in finding any good ones.
Are the tubes you suggest direct substitutes for the 8874s?
I am leaning toward buying a KPA1500 which would have many advantages for
me and the way I operate in Mali.
With kind regards,
Jeff
-----Original Message-----
From: Larry Dighera <LDighera@att.net>
To: Amps <Amps@contesting.com>
Sent: Sun, Oct 14, 2018 5:18 pm
Subject: Re: [Amps] KPA1500 in QSK mode
Hello Jeff,
Tubes are an issue for the 87A as well; that's for sure. Here are
some tubes to consider:
NEW GS-36B/4CX400A Tube, Tetrode, Russian
https://www.rfparts.com/catalogsearch/result/?q=GS-36B $174.95/each.
New old stock GS-36B tetrode
https://www.ebay.com/itm/263803841869 US $49.00/each.
Hope that helps return your venerable 76A to operational status.
Best regards,
Larry
On Sun, 14 Oct 2018 01:36:33 +0000 (UTC), <tz4am@aol.com> wrote:
Larry:
I have an Alpha 76A but have never succeeded in getting a good set of
tubes for it.
I like the KPA1500 but am hesitating for the same reason: price
Instant-on and 6 meters are a big draw for me too.
73,
JeffTZ4AM/K1MMB
-----Original Message-----
From: Larry Dighera <LDighera@att.net>
To: Amps <Amps@contesting.com>
Sent: Fri, Oct 12, 2018 12:00 pm
Subject: Re: [Amps] KPA1500 in QSK mode
Hello Bob,
I've been considering replacing my Alpha 87A
<http://kj6yvt.com/amplifier.htm> with an Elecraft KPA1500 too. The
instant-on feature solid-state amplifiers offer is attractive to a
fellow who hates to wait, and the 6 meter support and built-in antenna
tuner are what have lead me to this. The KPA1500's $5,995.00 price
tag is about double what I paid for my used 87A, and my 87A is
integrated with the Alpha DAS antenna selector relay control box, so
I'm still on the fence.
Thank you for posting the Alpha 87A memory dump procedure
<https://www.kkn.net/~n6tv/Alpha_87A_Memory_Dump.pdf>. That is
something all 87A owners will appreciate.
And I very much enjoyed your extensive 2018 Visalia International DX
Convention photo album <https://bit.ly/Visalia2018>.
Best regards,
Larry Dighera
WB6BBB
On Tue, 9 Oct 2018 23:45:07 -0700, "Bob Wilson, N6TV" <n6tv@arrl.net>
wrote:
Mickey,
I just used a pair of KPA1500s in the California QSO Party, full bore, CW
only, for 24 hours. The performance was solid, no glitches. QSK was
silent and fast, so it's safe to use a K3 transceiver in CW QRQ mode
(about
4.3 ms PTT to RF delay, maximum QSK performance). Fan noise was not a
problem while wearing David Clark headphones. I manually set the fan
level
to a minimum value of 2 (out of 5) which is pretty loud, but it kept the
temperature below 62°C, so the amp. never kicked into a higher fan speed.
I'm running a beta version of the firmware (1.78).
Though I use two K3s, the KPA1500 amp/tuner combo. can automatically
track
your 6600M frequency (see the USB Cables section in the Flex Manual). You
can use the XCVR SERIAL port on the KPA1500 for this. The S-BOX
<https://bit.ly/S-BOX> makes that connection easy using standard serial
and
TRS cables, no custom cables required. (The S-BOX can also do this for
SPE
and ACOM amps).
My Alpha 87As are now for sale.
73,
Bob, N6TV
On Mon, Oct 8, 2018 at 5:28 AM Mickey Baker <n4mb@arrl.net> wrote:
I have a fairly new 6600M and once had the PowerGenius on order, but
cancelled after it was delayed and my transceiver was ready.
I'm thinking that the Elecraft KPA1500 is the only full power solid
state
amp with qsk that can replace my AL1500 with QSK5.
Thoughts from the group?
Mickey Baker, N4MB
Fort Lauderdale, FL
*“Tell me, and I will listen. Show me, and I will understand. Involve
me,
and I will learn.” *Teton Lakota, American Indian Saying.
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