Dc Heaters / What diodes and questions.

[katopan]

Surely if the AC heaters were elevated there'd be no practical difference?

[Stevem]

Yup, I have done listening A/B test in regards to elevating the heaters and hear zero tonal difference !

[tictac]

When I was taking about tonal difference between DC and AC I was referring to pure DC supply not the DC reference derived from the bias supply which I've use in most of my builds as well.

I agree there doesn't seem to be a detrimental effect to the tone with a DC referenced supply, in fact I don't hear much of a noise difference either...

TT

[katopan]

Just to clarify I was talking about elevated AC heaters having the same benefits that people assume they'll get with DC heaters.

Elevate the AC and the heater electric field has very little effect on cathode electrons. ie. It removes the hum. Make the heaters DC and you risk getting rectification noise effecting the cathode electrons, which means you hear that instead.

[RockinRocket]

Good ac heater suggestions ill try. The 12ax7 will be enclosed in a Hammond box so it will be elevated flat in the box.