Plexi screen resistors- 2 watt okay?

[Madison]

Can I get away with using these 1K/2W on the EL34s?
I installed them but just want to be sure.
I don't have any 1K/5W here.
I do have 1.5K/5W.

[sluckey]

I think so. A 1K resistor would have to see 45ma to dissipate 2 Watts, or 31ma to dissipate 1 watt.

[jim]

I would use the 1.5 K 5W.  It is safer and the amp won't know the difference.  Jim

[Madison]

>> think so. A 1K resistor would have to see 45ma to dissipate 2 Watts, or 31ma to dissipate 1 watt.

Thanks!
I'll probably try set the bias so it can't adjust that high.
I am estimating about 400 volts on the plates with this amp.
42ma would be the max dissipation a guy would want to adjust to, I think?

>>I would use the 1.5 K 5W.  It is safer and the amp won't know the difference.  Jim

Doesn't the increased value reduce overall output?
And/or tone?

[Cups]

I don't think you'll be able to hear the difference in volume or tone. Could be wrong though. Why not try it out? Those are robust resistors and it's an easy enough swap.
I know I'd stick with the 5W but I'm cautious that way.

[sluckey]

I'll probably try set the bias so it can't adjust that high.
I am estimating about 400 volts on the plates with this amp.
42ma would be the max dissipation a guy would want to adjust to, I think?

You're thinking plate dissipation. Screen dissipation is much less, typically only about 10% of plate dissipation.

Fender used 470Ω/1W screen resistors on most all of their amps, big and small. 'Course I've seen several scorched screen resistors in Fender amps. 

[LooseChange]

The standard screen resistor for an el34 is 5 watts. Use the 1k5. You'll never hear the difference.

[Madison]

Thanks, LC.
I think I'll go for it.
I can't jeopardize my magic smoke.

Now that darn Sluckey.
That guy, he just left me hanging!
I mean good golly, I had to go out and read pages and pages about screen resistors and learn something new!

Oh......my head

Thanks again Gents.

[bigsbybender]

I tried 2w with EL34's with a plexi-ish amp I built and they turned brown, so I switched to 5w resistors. I have ever since on any amp I build that can take EL34.

[Madison]

I tried 2w with EL34's with a plexi-ish amp I built and they turned brown, so I switched to 5w resistors. I have ever since on any amp I build that can take EL34.

I figure the draw of 6L6s must be at the borderline for 1 watts?

Swapping them out right now.