Spec'ing current reqs on trafo secondaries
In spec'ing a replacement transformer for the failed one in my preamp, I'm being asked for the current requirements on the secondaries. Every calculator I find online is different to the others and am a bit confused at this point. I don't want to come up to speed on all the theory right now, I just want to the right value to give the transformer manufacturer, or a calculator I can easily use to get it.
The original Trafo is 15VA with a 1amp fuse on the live input, even at 110vac.
Secondaries:
23vac > diode bridge > 10k uF cap > 15v reg (+) > 10k uF cap
__________________> 10k uF cap > 15v reg (-) > 10k uF cap
9vac > diode bridge > 4700uF cap > 5v reg (single)> 4700uF cap
The 11DQ10 diodes each show a max handling of 1.1amp,and the regs are LM2940/LM2990 with slide on heat sinks.
It looks like the 5v rail merely handles the remote motor on the volume pot. The motor uses 150ma plus circuit. So I imagine most the current is for the 15v legs.
Last edited by brucew268; 18-04-2017 at 12:39.
Reason: corrections
Bruce
Theories are not so much answers as questions, to be supported or undermined by experience & testing.
Source: Audiolab 6000CDT > Calyx 24/192 DAC
Amplification: Pass-design B1rev2 pre-amplifier > Neurochrome Modulus 686.
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