Those with long memories will recall I was whining about insufficient
filament voltage in my (2)3-500Z amp...
Well, I solved that problem by biting the bullet and finding room on the RF
deck for the xfmr. Now instead of a pair of 7' runs of #10 (which
subsequent calculations showed was *not* sufficient!) I have a pair of 3"
runs. I was able to verify the xfmr using a bank of 6 1ohm 25W resistors
to duplicate the load of a pair of 3-500z filaments.
The amp is GG so there's an old B&W FC-30 (or could be FC-30A...don't know
'cuz the stickerplate fell off). Right now I'm getting 0.18V drop across
each choke...for a total of 0.36V. With a choke input of 5.00V (measured),
that's 4.64V at the tubes, I'M STILL A LOSER. Darn!
Well that drop seems awfully surprising for a choke supposedly rated at 30A
service.
So, here's the litany:
1. Are there known issues like this with the B&W FC-30(A)?
2. Any known OE's (Operator Errors) which could lead to this drop across
the choke?
3. ...each end of the choke has four terminals, apparently arranged in
pairs. If you mount the choke "on its feet" (it has little tab feet on the
bottom), the top two terminals are closer together than the left or right
pair (in other words, the four terminals form a rectangle that's longer
vertically than horizontally). *Which pair is the "choke"???? Ohming it
out won't tell me anything and I've never seen one in use!
4. Anything else?
Thanks again to the planet,
------------
Scott Townley
nx7u@primenet.com
------------
Collector of:
Stoddard Aircraft EMI/RFI receivers and accessories
Big Parts for that Big Linear Amp
70's era RF test equipment HP/GR/Tek
Radio-related technical reference material 1940+
...anything else that will keep me off the streets at night
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