#124 screen grid resistors

[Charles52]

My current project is a #124 low plates, non HRM with 2x 6L6. I see different versions of the screen grid resistors: 470 Ohm or 1 k. What do you people recommend and what is the impact of either?
Also, what would be the best feedback resistor for a 50 W. version?

Best regards,
Charles

[martin manning]

For the screen resistors, either value will work, and probably not make a noticable difference to the tone. Higher resistance would produce more compression, I would think, though. If you want to run EL34's at some point (and you have the sockets wired to accept either), go with the 1k to protect the screen grids. Some have gone even higher, to 1k5.

To get the same negative feedback in a 50W you need to decrease the 4k7 feedback resistor value by a factor of 1.4 to 3k3, since the voltage at the output is reduced by that factor. Alternatively, if you have an OT with multiple secondary taps, you could keep the same feedback resistor value and move the feedback from the 4- to the 8-ohm tap.

[Charles52]

Thanks Martin, then I will go for the 1k resistors.

Regards,
Charles

[gary sanders]

I have the 1k5 on mine,actually 1.6K.Thats all they had at ACK that day.It sounds great and Im going to try EL34 in it sometime