Don't think so...
The primary remains unchanged, as the for secondary with the '350FJ
you need 26.5V @ 0.65A per tube while with the '350A you need 6.3V
@ 2.8A - both about 17.5 watts (give or take).
So if your secondary has say 50 turns of 1.0mm diameter wire to
produce 6.3V for the '350A then its going to need 200 turns of 0.25mm
diameter wire to do the '350FJ (note that I am approximating since the
ratio for 6.3:26.5 is not actually 1:4).
As a result there is the *same* amount of copper on the bobbin - this is
to be expected as you need to deliver the same VA to the heater for
each tube type.
Actually there's an arguement that says the 26.5V transformer will be
*slightly* larger due to extra insulation layers as a result of more =
turns
(but this is being pedantic :-).
Mike G8TIC/M0VHF
(who has hand wound heater transformers for 4CX250B, 4CX350A and
4CX350FJs in his time...)
----- Original Message -----=20
From: K6KWQ@aol.com=20
To: mike.tubby@thorcom.co.uk=20
Cc: amps@contesting.com=20
Sent: Monday, November 18, 2002 12:25 AM
Subject: Re: [Amps] 4cx350f/j's
Your overlooking the secondary wire size you need to compare, I have
--- StripMime Report -- processed MIME parts ---
multipart/alternative
text/plain (text body -- kept)
text/html
---
|