Is it necessary? I'm building a phono-stage and am wondering if I need to twist the D3A and 5687 heater wires?
TIA
Dave
TIA
Dave
Not really (unless there's significant ripple on it), but the wiring is still neater when twisted.
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Twisted AC is better than poor "DC" in straight lines... without a giant cap or a MOSFET pass filter (or an SMPS in the first place), most times you're better off with well twisted wire and AC current.
Twists will reduce/prevent both pick-up and outgoing interference, for DC heater wires only pick-up is possible of course as DC doesn't generate changing magnetic fields. Noise pickup on the heater is unlikely to have any effect for an indirectly-heated device.
Thanks all. I think I'll twist them mostly as they will layout better. My first attempt with non-twisting them looked irregular and sloppy.
It certainly makes the wires a lot stiffer and therefore easier to route. If the wires were thick (nice margin wrt to ampacity required) and solid (as opposed to straned) and otherwise thoughtfully restrained, I bet untwisted would be ok.
It would be interesting to see some information on whether the common mode Chk route is more of a concern than the heater current mode.
As was and IS good practice when running heater wiring, particularly with preamp circuits, twisted pairs AND routing/dressing intelligently is the best result.
Down against the chassis, away from signal wiring.
It's the way that its been done for decades.
Down against the chassis, away from signal wiring.
It's the way that its been done for decades.