[AMPS] Alpha models: 91B vs. 89

[rhill]

Jeffrey Maass wrote:
> 
> I am attempting to select between the Alpha 89 and the
> Alpha 91B and would appreciate the advice of the experts
> here assembled. I don't require automatic bandswitching.

I am not an expert but just bought a 91B and it arrived last week.  So
far I think this is a great amp, easy to tune, very nice in appearance.



> I value equipment that will chug along at legal limit for
> the contest period without problems to distract me from the
> operation at hand. It will be used with my C-Line and
> FT-1000MP.

The WP3X team for the last cq ww wpx had one of the 91B's and they were
unofficialy number one in the world last week.  I was told by a team
member that the amp performed beautifuly.

> 1) Early 91B production was plagued with heat-related problems,
>     and at some point they replaced the Bulgarian blower with the
>     same blower used in the 87A. (The reporter said that this is a
>     different blower than that in the 89: true?) The cause of the
>     heat problems was later traced to the bias circuit and solved,
>     but the blower was not switched back.

The blower sure appears to be heavy duty.

> 3) The 91B is reportedly louder in operation (ignoring for the moment
>     the sound of the vacuum relay. I presume that this is the noise
>     of teh blower and (possibly) transformer hum. How significant is
>     the difference?

Not very loud. The relay is not noisy at all. 


> 5) Is the auxilliary fan a good idea for someone who will be making
>     contest use of one of these models? How much noise does it add?
 
I have this option, it is very nice.  Also, it is more quiet than my
computer.

I also would add that the staff at Alpha/Power are most helpful as I had
many questions regarding their products.  Delivery is fast, but prices
are going up 10% or more by June 15th.
73
Bob N8WFL rhill@htonline.com

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