Paul Ruby zener trick lowers cathode voltage?

[dinkotom]

I made an ODS (2. gen) amp with cathode biased 5881. I wanted a smoother drive, so I put that Paul Ruby zener trick in it:
http://www.paulamps.com/18watterbuzz.gif
I had 35V on the cathodes, so I put 36V zeners, but the cathodes voltage then dropped to 28V.
Is this OK or should I try zeners of different voltage?
Thanks,
Dinko[/img]

[pdf64]

I suspect there's a mistake somehow, as the zeners in the grid circuit can't affect the static cathode voltage (assuming that it was static voltages that were being referred to).

[katopan]

36V zeners will conduct current away from the cathode resistor. You need more difference between your 35V bias and the zener voltage of the diodes you're using. Go for a higher value.

[dinkotom]

Thanks, I have 39V zeners, I'll put them in and listen.
Here's the sound (with Supro lap steel):
https://www.youtube.com/watch?v=Q0-c_j7_ftk
The single strings sound OK to me, but when I play those thirds intervals on two strings (from 9. to 13. seconds on this clip), it sounds a little bit too muddy. I'd like to keep the drive, but lose a little bit of mud.

[pdf64]

36V zeners will conduct current away from the cathode resistor

If they're in the grid circuit and under static conditions, I don't see how that can be?