Preamp Headphone

reglys · 2176

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Offline reglys

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on: April 09, 2022, 03:21:36 PM
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 



Online Paul Joppa

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Reply #1 on: April 09, 2022, 05:09:10 PM
This is universally accepted as an unsafe practice. It's like removing the brakes on a car to save weight.

Paul Joppa


Offline Doc B.

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Reply #2 on: April 11, 2022, 08:14:23 AM
They used to make radios like that in the 30s and 40s. They were called widowmakers for reason.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Thermioniclife

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Reply #3 on: April 11, 2022, 12:06:39 PM
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.

Lee R.


Offline reglys

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Reply #4 on: April 11, 2022, 12:26:04 PM
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.



Offline Paul Birkeland

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Reply #5 on: April 11, 2022, 12:31:13 PM
You could certainly use a 6V wall wart to power your heaters.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man