3CX800A7 tube replacements for Alpha 87a amp
Bill Axelrod
For anyone still using a 3CX800A7 tube in an Alpha 87a or other amp…
The finals in my older Alpha 87a amp were going soft and got to the point where I could only get 1000 watts out even with 80 watts of drive on 17, 15, 12, and 10 meters. I could get the legal limit on the lower bands with reasonable drive.
So, I bit the bullet and decided to replace the finals. Then I saw the cost of new EIMAC 3CX800A7tubes which were a bit north of $1,000 each. So, I decided to cheap it out and bought the Taylor tubes which are made in China. Got them from RF Parts for less than $1K for a pair. I was nervous about not using the EIMAC tubes but figured it was worth a chance.
The tubes arrived today. I put them in today. They work. I can now get the legal limit at between 40 and 50 watts drive on any band. So far, so good.
There’s no guessing how they will do in the long term. Hopefully, they will last.
73… Bill K3WA
Mac English
Just for grins I got a quote today for s pair of those same tubes today from Richardson electronics for $1700. I paid $800 for a new pair back in 1999 from them. These tubes must be a rare animal. Those tubes are doing very well today in my 374A I bought from WB9Z in 1997. This amp is now 30 years old and still going strong. KM9Z |
From: Bill Axelrod <bi...@axelrods.org>;
To: CIDXCA <cid...@googlegroups.com>;
Subject: [cidxca] 3CX800A7 tube replacements for Alpha 87a amp
Sent: Fri, Oct 25, 2013 12:27:48 AM
Jerry Rosalius
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Mac English
Thanks Jerry. I am sending the 374 out to N4UQ to have it gone thru and do some updates to the air variable caps. When I get it back it will be good to go. I may do the third tube mod on it as I have a spare. That upgrade is about $289. The other day I had enough of that RCA jack and did the SO-239 mod for the RF input. Hope all is well for you... |
From: Jerry Rosalius <jerr...@gmail.com>;
To: <cid...@googlegroups.com>;
Subject: Re: [cidxca] 3CX800A7 tube replacements for Alpha 87a amp
Sent: Fri, Oct 25, 2013 12:42:17 AM
Bill Axelrod
And congrats on the Z8, Mac.
73… Bill
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