Triode-Pentode screen resistor.

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leadfootdriver
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Triode-Pentode screen resistor.

Post by leadfootdriver »

I wanna' put a triode/pent switch on my little single ended project amp. The amp used to be a Crate V58, but I scraped everything and added my own board, but used the hardware from the original Crate.

In the Crate schematic, there was no screen resistor between the output tranny and the single EL84. I followed suit with that. However, I seen the schematic of a VHT Special 6 where they use a 3 watt 470R on the screens of the single 6V6. That amp has a triode/pent switch as well.

Can a single EL84 handle triode mode with no resistor between the screen and plate? How does a screen resistor affect the tone anyways?
bluesfendermanblues
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Re: Triode-Pentode screen resistor.

Post by bluesfendermanblues »

The Blackheart BH5 use an EL84 and has a triode/pentode switch
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leadfootdriver
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Re: Triode-Pentode screen resistor.

Post by leadfootdriver »

I'm going to the local spot to pickup a switch. I can't make out the value of the resistor tho. Do you know the value?

Thanks btw.
rfgordon
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Re: Triode-Pentode screen resistor.

Post by rfgordon »

That screen resistor helps restrict screen current flow. In pentode/tetrode connected amps, that resistor can be fairly large, say 1k5 or so. In most triode connected amps, like a lot of hi fi stuff you can look up, smaller resistors are used. Common values are 100R or 300R.
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leadfootdriver
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Re: Triode-Pentode screen resistor.

Post by leadfootdriver »

Thanks for the help fellas!
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