Screen resistors....on tube socket?

[iknowjohnny]

I'm going to be building a new board and pretty much re-do'ing my amp in general. I had the screen resistors for the EL34's on the board before, but this time to save space i want to mount them on the socket. However, what i want to know is when people put them on the socket, where does the B+ end of the resistor go? Am i right to assume they wire pin 6 which has no connection in a EL34 to the B+ and thats where the other end of the screen resistor goes?

[jjman]

Usually, yes. Some let it fly in the air.

[paulster]

I always use pin 6 as the anchoring/B+ point as those resistors are heavy enough to warrant being securely fixed.

I tend to put them outside the tube socket, between pins 4 and 6, allowing the grid stopper to mount vertically at pin 5.

[Andy Le Blanc]

You can have them on the socket like in the fender layouts.
You can stand them up off the socket.
you can use a terminal strip to anchor them off the chassis.
I like to secure both ends, especially if you intend to used and over sized component.

[iknowjohnny]

Ahhh....grid stoppers too eh? I was going to have those on the board but that might be a good idea since i need to save space. But isn't that a bit worrisome? I mean, the solid and rather thin leads on components seem prone to breakage if they aren't solidly mounted on both ends. Thoughts?

EDIT: andy was faster than me. Good idea with the terminal strip. I do that with the input grid stopper so i guess i should with the PT stoppers as well and use pin 6 for the screens. That will save me the space of 4 components on the board and help me get everything i need on it. (i put PSU caps on the board so that takes up a lot of real estate)

[Andy Le Blanc]

grid stoppers need to be right on the socket pins, put them right on the end
of the grid lead wires and cover with heat shrink, they are usually small,
you can dress them right to the wire end.

[paulster]

I concur with Andy. That's exactly how I do it.

I use the Belton octal sockets with have two eyes per terminal so you can get the resistor lead through both of these to really firmly anchor it.

The heatshrink acts as a nice strain relief for the grid wire.

[iknowjohnny]

I use belton octals to. On the grid stoppers....why do i often hear it said they should be on the socket? I have mine on the board now, but i don't think it contributes anything undesirable does it? Whats the reason?

[Andy Le Blanc]

grid stop, the most effective place is on the socket pin, otherwise your
still left with a length of the grid lead that creates more of the dress issue
your trying to eliminate with the stopper.

[paulster]

Parasitic oscillation suppression, which power tubes are susceptible to and is usually well outside audible range so the first thing you know about it is when you start to get red-plating for no apparent reason even with sensible bias.

[iknowjohnny]

Thanks. Definitely going that way then.

[Andy Le Blanc]

Thank you...

Tubes were first developed for radio, the grid lead acts as an antenna....
the extra resistance "stops" the pick up of EM trash.

[Structo]

Yeah, I like using a one lug terminal strip for the screen resistors.
Both resistors and the wire from the screen supply go to the lug on the strip, the other end goes to pin 4 and the swampers on the socket on 5 & 6.