Preamp Headphone

[reglys]

Hi

If we forget the 6.3 Vac voltage needed for the tube heaters, would it be possible to get enough DC voltage for the output tubes by rectifying 120 Vac powerline without a power transformer in a headphone preamp for instance.

Thank you in advance 

[Paul Joppa]

This is universally accepted as an unsafe practice. It's like removing the brakes on a car to save weight.

[Doc B.]

They used to make radios like that in the 30s and 40s. They were called widowmakers for reason.

[Thermioniclife]

Yeah. also called curtain burners. Many old tube radios have a built in resistance in the power cord that if replaced with a modern cord disaster is sure to happen. Also they were designed for 110 Vac.

[reglys]

Yes I understand at that time they had plug with 2 prongs and they didn't care about the polarity and you could have a hot chassis.

However it is amazing when we see what Apple is doing with their tiny IPAD power supply . First time I used it in Paris, France during an oversea trip, I was sure this tiny power supply will blow out at 230 Vac.

[Paul Birkeland]

You could certainly use a 6V wall wart to power your heaters.