dual primary//dual secondary toroid

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My question is: four primary leads-- 0v white; 117v yellow (first primary) (second primary)-- 0v orange; 117v black.
The dual secondary is 24v x two.
Product note states; primary leads connect in series or parallel.
117/234 v. Should the secondaries connect to a single primary(117v)? Or, can they be connected; primary 1 to secondary 1 &
primary 2 to secondary 2? Note: will use 2 bridge rectifiers
Help will be 'much' appreciated. larryg
 
THANKS FOR YOUR REPLY RICHIE&NUUK. IN USING THE WORD
[ CONNECT ], I MADE A POOR CHOICE IN MY POST. I DO KNOW
THE PRIMARIES(ONE OR TWO) CONNECT TO THE MAIN, THE SECONDARIES TO RECTIFIER(S), FOR THE REQUIRED DC. THE MAINS, FOR THE U.S., IS 117V. SO FOR THE TRANSFORMER, ONLY
0NE OF THE PRIMARY LEADS IS CONNECTED TO THE MAINS,117V.
FOR MAINS OF 234V, BOTH TRANSFORMER PRIMARIES ARE USED.
IS THIS CORRECT? IN FUTURE POSTS, I WILL PAY MORE ATTENTION IN CHOICE OF WORDS!
THANKS, larryg
 
Hi,
will use 2 bridge rectifiers
why?
one rectifier will do the job and is cheaper/simpler.
You can use two rectifiers to get a slightly increased current if your diode bridge is too near it's rating limits.

If you use only one 117V primary you will massively reduce the VA rating of the transformer. It will be either 50% or 25%, I can't get closer than that.
 
Hi,
are you building two channels?

Then use one diode bridge on each channel, each channel with it's own rectifier and smoothing bank.

If you adopt the dual, series connected diode bridges you will need two for each channel.
If you decide to use a dual bridge and share the +-supplies between channels, I think you will end up with poorer performance than using independant rectifier/smoothing bank per channel.

I have tested, using the equipment available to me, both types of rectifying scheme.
Type 1: The single rectifier using centre tapped transformer into series connected smoothing caps and taking the centre tap and the cap common (0Volt) to audio ground.
Type 2: dual rectifer using twin secondaries from transformer into independant smoothing caps and taking +ve from one cap and -ve from the other cap to the audio ground.

I have connected both types into two different amplifiers and all four combinations have immeasureable hum and buzz and noise on the output of the amplifier. Both types appear to have the same ripple on the supply rails. Type 1 produces about 1.6V extra DC.
I used a DMM with 200.0mVac scale rated from 20Hz to 500Hz with extended but inaccurate response out to about 100kHz (-8db) and a scope with 1mV/div vertical sensitivity. I plan to increase the sensitivity of these tests, so this is not my final report nor conclusion.

My recommendation is, go the simple, cheap, single route with the diode bridge. Add RC snubbers to each diode.
Take the 0volt common TO the audio ground.
DO NOT bring the audio ground to the rectifier common connections.
 
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