[TenTec] Omni VI and non TT Amp

[waltk8cv4612amos at att.net]

Oh my, extremely bad suggestion! Put a muffin fan or two on top to blow air 
out, that should help some.

Walt K8CV Royal Oak, MI.

----- Original Message ----- 
From: "Rick, NJ0IP / DJ0IP" <Rick at DJ0IP.de>
To: "'Discussion of Ten-Tec Equipment'" <tentec at contesting.com>; "'Rick 
Denney'" <rwd at iteris.com>
Sent: Thursday, November 08, 2007 7:38 PM
Subject: Re: [TenTec] Omni VI and non TT Amp


> Chas,
>
> I am not familiar with the internal layout of the AL 811A amp.  When 
> running
> a continuous duty cycle mode, I would be sure that the power supply's
> electrolytic capacitors get enough cooling (i.e., probably use an 
> additional
> fan).  You might want to check how hot they get (before the contest 
> begins),
> by feeling them with you hand after a long transmission or two, but BE 
> SURE
> TO TAKE CARE when dealing with an open chassis and high voltage!
>
> 73
> Rick
>
> -----Original Message-----
> From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
> On Behalf Of Charles Greene
> Sent: Thursday, November 08, 2007 4:42 PM
> To: Rick Denney; Discussion of Ten-Tec Equipment; Discussion of Ten-Tec
> Equipment
> Subject: Re: [TenTec] Omni VI and non TT Amp
>
> Rick and All,
>
> I have a Ameritron AL0811A with three 572B tubes.  The power output
> is about the same with the 572Bs as with the 811As on SSB or CW
> because the power output is limited by the power supply voltage and
> current.  However, the 572Bs have much more plate dissipation than
> the 811As, so I can safely run 400 or 500 watts output using PSK31 or
> RTTY, a practice that would overheat and warp the plates of the
> 811As.  When I acquired the Al-811A amp, it needed new tubes anyway,
> so I just bought 572Bs, and did not change the amp in any way.
>
> Chas W1CG
>
>
> At 12:06 AM 11/7/2007, Rick Denney wrote:
>>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 at iteris.com           |Sterling, VA 20164        |Fax 703.471.1757
>>
>>_______________________________________________
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>>
>
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