Tube Biasing

[Steve L]

I just put in a JJ E34L into my Carr Mercury. Replaced a KT-66.
This is the first time I've ever done a tube replacement!! Pretty easy, actually.
However, I have noticed that the bias level seems to be changing from time to time. Is that normal while the tube "breaks in?" Nothing dramatic, just goes up and down about 3-5 points.
If it's normal, how long does it take to stabilize?
(The Carr Mercury is a great amp!!)
Thanks.

[Blue Strat]

By 3 - 5 points, do you mean 1/10ths of a mA? If so, that's pretty normal. In general, wait about 5 minutes after powering up for things to stabilize.

[Steve L]

By 3 - 5 points, do you mean 1/10ths of a mA? If so, that's pretty normal. In general, wait about 5 minutes after powering up for things to stabilize.

I suppose! It goes from about 45 to 48...and sometimes it's down to 43 or so. I'm not sure what it is I am measuring, obviously! I had to go out and buy the multimeter! Never used one before....
When you say wait five minutes, is that with the amp "on" or in standby? That is, I was told to measure the level with "no load" on the amp. (Therefore, I measured it in standby mode after sitting for about a minute or so. With the input cord unplugged from the amp.)
Thanks for your quick response!!