[Amps] filament transformers

robert briggs vk3zl at bigpond.com
Sat May 16 01:53:07 PDT 2009

What has happened to "roll your own" custom filament transformers? I 
have never purchased a commercially made filament transformer after 
building more than 40 amplifiers over 25 years....I still roll my 
own...There are plenty of sources of suitable transformers including 
older type video recorders small TV sets and a few other redundant  
pieces of  old electronic equipment..Once you find a transformer which 
is appropriate for the job at hand all it takes generally is the 
patience to disassemble it and rewinding it with  appropriate  size wire 
for the job...I always  wind an extra half volt or so and use a dropping 
resistor in the primary to obtain the correct voltage at the tube 
pins....This resistor also acts as a surge protection for inrush current 
on switch on...I also rewind these transformers for relay and control 
voltage sources....Cheaper than buying them and more reliable as you can 
set them up exactly as you want them..

73....Bob VK3ZL..

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