High current filament chokes should be bifillar would. This reduces the 60
Hz field in the core which could modulate the reactance of the choke and
introduce 60 Hz hum on a carrier. The 60Hz current is much greater than
the RF current thru the choke.
73
Bill wa4lav
At 12:13 PM 1/3/2003 -0500, Bob Maser wrote:
>Can anyone tell me what inductance do I need in the filament choke for a
>3CX3000A7 for 80M. I built one back in the mid 90's and had to wind one
>around 3
>ferrite 1/2" rods in order to keep the AC out of the tube(or was it to keep
>the RF out of the transformer?). I have some filament chokes wound made
>with 10ga
>wire and they measure ±45uh. I guess I could always put 2 of these chokes in
>series but they would take up more real estate under the chassis.
>
>BTW, anyone interested in a swap, my 2 8877's with filament xfmr and
>sockets and Teflon chimneys for a 3CX3000A7, socket and xfmr??
>
>Thanks for all the advise on gluing up Silicone sheet into chimneys.
>
>Bob W6TR
>
>
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