Belles 21A standby mode?

There is not going to be a change in intensity of the light emitted from the tube filaments. The power to the filaments remains the same on or off. It's the other circuits you change.
1markr, care to comment on the comparison between the L-2 and the Belles 21A sound wise? I also have the L-2 but looked hard at the Belles. I didn't get to demo the 21A. I'm using the AI with a Belles 350A.

If that's the case, then I probably shouldn't worry.
Thanks everyone for responding !!

Bigtee...I'm not quite prepared to comment on the either the L2 or 21A, other than they both sound very nice and I could easily live with either of them. I just got the L2 less than a couple of weeks ago, and the 21A a week or so before that. These replaced a very highly regarded 51SE, which just did not work well in my system at all. In my system, to my ears, either of these preamps sound much better, at a quarter of the price.

In a few weeks, I should be able to formulate a meaningful comparison, as I'm going to keep only one of the preamps when all is said and done. I'm working on rolling the best tubes into these two preamps now.
The 21A, so far is just a tad noisier than the L2, but that could be tube related, thus the tube rolling.

I'll keep you posted.

I'm still trying to find out if the 21A has a standby mode, and if I'm missing a jumper.

1markr, I received my L-2 Christmas day(actually arrived). I'm very impressed with it and feel it was a definite improvement over the L-1 I had previously.
Why don't you call Dave Belles and talk to him about your questions. I would think that it would have a standby mode that at least keeps the filaments heated like the AI.
Let me know about your final decisions on the preamps.

Maybe this an apples to oranges comparision...
I also have a Belles 20A, plugged it back in, power swich off and there is a faint glow on the filaments. When powered on, the glow reaches the intensity that I see with the 21A powered off.