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Hoffman Amps Forum image Author Topic: Amnesia, didn't remember how to guess load in SE & PP .... ????  (Read 1919 times)

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Offline kagliostro

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Some time ago somenone explained me how to gues the correct load for SE & PP

this using the tube plate max dissipation and the voltage of B+

to me seems that for SE the formula is Zout = Va/(Pa/Va)

I remember that DummyLoad and PRR gived some explanations to me but, unfortunately, my brain don't want to collaborate

Please can someone help me to remember ?

Many Many Thanks

Franco

The world is a nice place if there is health and there are friends

Offline sluckey

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Re: Amnesia, didn't remember how to guess load in SE & PP .... ????
« Reply #1 on: August 21, 2022, 08:31:51 am »
Maybe this...
P = E2/R so R = E2/P

example...

    plate voltage = 300V and PdMAX = 15W
    3002 / 15 = 6000Ω

A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline kagliostro

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Re: Amnesia, didn't remember how to guess load in SE & PP .... ????
« Reply #2 on: August 21, 2022, 09:26:06 am »
Ciao Steve

Thanks

Seems that for SE Class A

P = E2/R so R = E2/P

&

Zout = Va/(Pa/Va)

Gives te same result

R = E2/P  ....... 300x300/15 ....... 90,000/15 ..... 6.000

Zout = Va/(Pa/Va) ..... 300/(15/300) ..... 300/0,005 ..... 6.000

Beautiful .... and for PP what we do ? we moltiply by 2 to estimate aa value ?

Thanks

Franco
The world is a nice place if there is health and there are friends

Offline sluckey

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Re: Amnesia, didn't remember how to guess load in SE & PP .... ????
« Reply #3 on: August 21, 2022, 10:27:55 am »
P = E2/R so R = E2/P

&

Zout = Va/(Pa/Va)

Gives te same result
Of course. They're the same equation, except yours has not been simplified.  :icon_biggrin:
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline kagliostro

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Re: Amnesia, didn't remember how to guess load in SE & PP .... ????
« Reply #4 on: August 21, 2022, 12:15:31 pm »
😁😁😁😁

OK, my brain Is officially lethargic

Franco
The world is a nice place if there is health and there are friends

 


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