Rick
The better reliability of the 572's is not just a "perceived" improvement.
The 572's have about twice the plate dissipation of the 811a's and they were
designed to run at a much higher plate voltage. Running in place of the
811's at the lower voltage, the 572's should last forever, whereas the
811a's are prone to frequent popping under contest or heavy-use conditions.
Most reports I've heard from people replacing the 811a's with 572b's in the
Ten-Tec Centaur have been nothing but positive!
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Rick Denney
Sent: Tuesday, November 06, 2007 11:07 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Omni VI and non TT Amp
Ken Brown writes...
> Last time I had an amplifier using anything like 811A tubes, they
> were actually 572B, and it took two of them to get 650 to 800 watts
> out. It was a Heath SB-200. Is that really an 811A?
I was talking about the Ameritron AL-811a amplifier, which uses three
811a transmitting tubes, not the tube itself. The 572b tubes are
indeed capable of greater output because of their higher plate
dissipation rating, their greater grid current rating, and their
higher plate voltage. Yes, the 572b is "like" an 811a tube, and some
use them in amps designed for 811a tubes because of their perceived
greater durability, but they aren't really the same.
Rick, KR9D
---
Richard W. Denney, Jr. PE|Iteris, Inc.
Associate Vice President |107 Carpenter Dr. Ste 230 | 703.925.3819
rwd@iteris.com |Sterling, VA 20164 |Fax 703.471.1757
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