[Amps] Replacing 811A with 572B

Bert Almemo balmemo at sympatico.ca
Wed Apr 9 20:23:19 EDT 2008


Thanks for all your replies. It seems I was misinformed and have learned
something new. I thought the parameters were different in the 572B but I
know better now. Thanks guys!

73 Bert, VE3OBU
 

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Paul M Dunphy
Sent: Wednesday, April 09, 2008 7:46 PM
To: amps at contesting.com
Subject: Re: [Amps] Replacing 811A with 572B

At 08:37 PM 4/9/2008, Bert Almemo wrote:
>Hi guys,
>
>I have a friend who wants to replace 4x811A with 4x572B in an Ameritron
amp.
>I don't think it's a good idea but he insists a lot of hams do it. What 
>do you think?
>
>73 Bert, VE3OBU

     It's a good move.  They are physically and electrically very close.  I
did it with the AL-811H and instead of going through one or two of those
Taylor Chinese clone 811As a month I never had to replace a tube again.
They are running at about 2/3 their voltage rating (the 572Bs) in an amp
designed for 811As.  You can't get any glass tubes that are made in NA
anymore, but if you substitute imported 572Bs for imported 811As.

     I have since sold the amp in favour of an ACOM-1000, but the guy who
bought it a year ago still has the 572Bs in it.  The only thing is that
Ameritron won't honor the warranty if you do this, so wait until the amp is
a year or more old (and thus off warranty.)  I even discussed this with one
of the techies at Ameritron and he said the switch to 572Bs was a good idea,
although he couldn't "officially" 
recommend it.

73, Paul VE1DX
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps

No virus found in this incoming message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 4/9/2008
7:10 AM
 

No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.22.10/1367 - Release Date: 4/9/2008
7:10 AM
 



More information about the Amps mailing list