Screen Voltages

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Structo
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Screen Voltages

Post by Structo »

For the guys that run a choke in their 100w ODS amps, is your screen voltage at pin 4 of the 6L6, less than your plate voltage at pin 3?

I ask this because in my amp, the voltages are virtually identical.
That is they are both 433v.
I used a Magnetic Components choke that is spec'd at 4 henrys @ 90ma.
I don't know what the DC resistance is.

I have 6W 500 ohm screen resistors on each socket.

I haven't checked to see what the screen voltages do once I am playing through it, only at an idle.

Is this something to be concerned about, as in, am I harming my power tubes by having the screens the same voltage as the plates?

I thought the idea was to have the plates more positive than the screens for cleaner operation.

Thanks for any input.
Tom
Last edited by Structo on Wed Nov 10, 2010 7:05 pm, edited 1 time in total.
Tom

Don't let that smoke out!
mlp-mx6
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Re: Screen Voltages

Post by mlp-mx6 »

Is your meter True RMS?
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Structo
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Re: Screen Voltages

Post by Structo »

Yes
Tom

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mlp-mx6
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Re: Screen Voltages

Post by mlp-mx6 »

My 100W w/ choke measures about 1V lower on the screens, and runs fine.

I simply take that to mean that there is not a lot of screen current (or downstream in the PS either) to pull the voltage down.
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ChrisM
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Re: Screen Voltages

Post by ChrisM »

Didn't you ask this before on your D'lite? Like I think you said the screens were only 2-3V below.

Anyways thats normal. They will drop while playing.
BobW
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Re: Screen Voltages

Post by BobW »

FWIW, It doesn't matter if you have a true RMS meter when measuring voltage from a DC source.
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David Root
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Re: Screen Voltages

Post by David Root »

Both my D-style amps have chokes and they do the same thing Tom, I would only be concerned if the screen was higher than the plate.
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Structo
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Re: Screen Voltages

Post by Structo »

Thanks guys! :D
Tom

Don't let that smoke out!
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