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Hoffman Amps Forum image Author Topic: Is this an improvement to virtual earth on heaters PS ?  (Read 1742 times)

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Offline kagliostro

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Is this an improvement to virtual earth on heaters PS ?
« on: April 24, 2017, 06:06:59 am »
I've seen this schematic and I would like to know if it worth to apply it on guitar amp circuits

a 20K pot will not require to be a high W rated unit because of the small current crossing it (also if paralleled with 2 x 10K resistors)



Thanks

Franco
« Last Edit: April 24, 2017, 06:09:29 am by kagliostro »
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Offline PRR

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Re: Is this an improvement to virtual earth on heaters PS ?
« Reply #1 on: April 24, 2017, 11:00:15 am »
That is said to be for "direct heated" tube. None of our usual g-amp tubes are direct heated.

Even used as claimed, it makes no sense. The cathode current must flow in several K Ohms of variable resistance, much more resistance than we usually put in a cathode return.

I think someone didn't think about it.

> 20K pot will not require to be a high W rated

6.3V in 500 Ohms is less than 0.1 Watts.

Offline kagliostro

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Re: Is this an improvement to virtual earth on heaters PS ?
« Reply #2 on: April 24, 2017, 11:21:47 am »
Thanks for the answer PRR

Franco
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