el84 triode strapped questions

[walkman]

should be the plate load be for a el84 strapped as a triode at roughly 250v and 35ma be 3.5k as per the data sheet ?

or would it be equal to 250 / .035 = 7124 or 7k real world

what other options are their for triode configuration besides jumping pin 7 and 9 with 100ohm ?

i read wiring a diode between 7 and 9 would prevent screen signal joining with the plate .. is that worthwile?

[6267]

My datasheet says the same thing for the SE EL84 triode strapped. This would be as easy as simply connecting a 4-ohm cab where you probably had an 8-ohm speaker, or a 4-ohm speaker of course. It'll probably be ok into the 8-ohm speaker, you'll just have low power. Don't push the voltages though. My datasheet also says that for push-pull 300v anode with 270k cathode resistors (each tube) that the load resistance a-a is 10k, so in p-p at least you can switch pentode/triode without really affecting optimal load too much.

The UKers like to call ultralinear "super triode" mode, which is essentially true. I've also heard of "screen-driven" triode mode, but this generally requires fairly specific tube characteristics and often a solid-state MOSFET low-z out stage to drive them. The power out is not reduced in this mode. Try searching over at diyaudio.com, lots of questions about triode mode there due to the hifi focus common on that site.

[walkman]

To me the triode sound of an el84 is much smoother when run flatout .... as a pentode it seems too gritty too harsh running at 250v on the anode,

both with triode or pentode i have been using a 7k primary to 16ohms with a 16ohm speaker.


Yes it is meant to be a recording or practice amp but it really is still too loud for others around me.

I was wondering how in triode mode the load should be 3.5k at 250 and .035ma ( 270 ohm cathode bias ).

Is the normal way to calculate load the voltage at the plate divided by the current
or it it halved as the screen and plate are joined or triode mode?