Nick Gorham wrote:

Ian Iveson wrote:

Also wondering why the OP configures the filament regulator
as a current source. More efficient for many filaments
because they can be stringed in series, but I can't see why
it's better, for a single filament, to use a high-impedance
supply.


The reason I do it that way is it sounds better. I believe the reason it
sounds better, is some of the signal appears across the fill in a DHT,

If some of the signal appears across the filament then the regulator isn't
doing its job.


and the voltage reg will try and regulate that away, with a current reg,
the signal is common mode, so not affected.

UH ?


Voltage reg certainly sounds worst than AC heating, but I think current
reg is as good as AC without the problems of AC.

Just my theory of course, so expecting to be wrong.

How utterly bizarre !

Graham