Re: simple center tap for transformer, originally without one.
Hello,
Even more simple to add a center tap lead to your transformer...
is to include a low value resistor from each side of the
transformer lead to ground or your dc return path
A pair of 10 ohm resistors would use less than a 1.5 watts of power.
This was "a trick" I learned from an old Ham Radio project book
that I'd love to find another copy of some day (101 Easy Ham Radio
Projects). It worked very well for my "poor mans 2x 811a amplifier
still cooking along just fine.
The choke idea is also interesting...
cheers
skipp
:"I am building an amp with four 3-500Z using low bands only (160 and
:80m). I do have two filament transformers, 5V/80A w/o a center tap on
the
:secondary coil. The other one contains four coils with 5V/25A ea. coil
:also w/o any center taps on the secondary side." (Etc.)
:How about connecting a small "audio" or "power supply" choke from each
:side of the secondary to "eventual" ground? Calculate the inductance
:value of them so that they will only allow a negligible (AC) current
:flow to ground while maintaining a balanced condition for all voltages
:involved in the circuits. I think reasonable sized, cheap chokes may be
:possible but must have low DC resistances. Maybe from junk box.
:73, Roy K6XK
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