voltage divider for screen grids

[ChrisM]

Yes, when I have measured the voltages to ground the plate and screen are about the same.

Andy had suggested measuring them at the socket to see the difference in potential between them.

The same or about the same?

This is where a good accurate meter is helpful, one what displays a couple significant digits after the decimal point.

[markr14850]

This measurement seems odd to me. The plate supply will have a ton of ripple on it. There will be much less on the screen supply (and it will be slightly phase shifted). Any numbers that your meter shows you when comparing these two will totally depend on how your brand of meter integrates the ripple AC component.

[Structo]

Well I say about because the reading was jumping around.

Mark, what you say makes sense.

I have a Meterman 37R which is supposed to be equivalent to a Fluke.

[Andy Le Blanc]

I hadn't run into excessive ripple on plate voltage, yet...
Been thru a pile of different amp brands too...
Yes try measuring the difference, it was happenstance that I measured it there.
And I was surprised that it has been a stable reading in so many amps...
try the difference and don't assume the ripple will be an issue before you try it

crazy ripple would be a problem to itself, bad cap or poor parts value selection, ground on the power rail, not enough current flow or minimal voltage drop to make for an effective filter stage.

I use krapp meters, I'm cheap and and don't mind pitching one if it gets cooked.
I bet the sensitivity in mine is low, but it will measure o.xxx ma., its a guitar amp after all...