>Jeff,
>
>If you have another kilobuck to spend , don't think twice.
>If you don't have , find it. There are no advantages on 91B
>over 89A. If you want superior reliability, quality and performance,
>go for american made parts only.
>
>
> Alpha 91B Alpha 89
>
>>Tubes (2) Svetlana 4CX800A Eimac 3CX800A7
>
>There is a big difference between the two brands.
>
>>T/R Vacuum relay PIN diode
>
>PIN switching is quieter and faster and I heard that they solved
>the first series problems.
>
>>Transformer 3.5kVA Unisil-H ? kVA Hipersil
>
>Go for US-made hypersil.
>
>>Input Tuned input not req'd Tuned Input
>
>Tuned input is expensive but is a "must" not only for purists.
>
>>Parts Source Bulgaria, Russia, USA USA
>
>No comments.
>
>What about the spectral purity ? They cannot be compared.
>
>>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?
>
>If you like SSB contests with processor and vox , it makes a big difference
>
>
>>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?
>
>This is a good ideea for contesting.
>
>
>73 de Morel, 4X1AD
>
>
>
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