On Wed, 24 Mar 1999 12:07:38 EST G3CWI@aol.com writes:
>
>I pick up 4 new 4CX250BM valves at a hamfest recently. Does anyone
>know a
>source of a design using 4 valves for the HF bands? Presumably they
>can simply
>be operated in parallel but will I need independent bias adjustments
>for each
>tube?
For reasonable matching you can install individual bias pots and do a
simple static adjustment for equal idle currents. Not as good as dynamic
balancing but close.
The Tokyo High Power HL-1K used a pair with cathode drive and excellent
IMD. You might get a copy of that manual and go from there. It may have
been sold under a different name in the UK.
73 Carl KM1H
>
>73
>Richard
>G3CWI
>
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>
>
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