change input resistor on tube amp?

[tempus]

Hey all;

I've got a Carvin X100B tube amp. The input resistor to ground is 2.2M, which seems a little high to me. Can I just switch it to a lower value (say 1M or even 500K) safely (i.e., without damaging anything)? I'd like to see if the lower value reduces noise or affects the tone, assuming it doesn't go to low and start loading the pickups.

Thanks

[iccaros]

you could, but it would not reduce noise IMHO, it set the impedance for both sides of the first tube so effective I see it a 1.1M

http://www.carvinmuseum.com/pdf/amps/s24104N_X100B_schematic.pdf

to effect tone C2 is one place to start for lead tone, you have  allot of silicon in there that can also effect tone

[Derringer]

I agree with iccaros.

Does the amp still make noise when nothing is plugged into the instrument input?

[tempus]

Thanks for your replies.
The correct schematic is located at:

http://www.carvinmuseum.com/pdf/amps/x100b-preamp-3-28-82.pdf

I appreciate the opinions. So it wouldn't do any harm to the amp to reduce it? I'm talking more about hiss than hum, and also have been interested in a discussion that brought my attention to this:

http://www.carvinmuseum.com/pdf/amps/VL100%20&%20VL212%20Legacy%20Amp.pdf

Apparently a great sounding amp, but with a much lower input Z. I'd just be interested in trying it out to see what it sounds like.

[iccaros]

also a totally different arrangement. both schematic's are essentially the same, one showing the entire amp on one page the other just the preamp.
The x100b splits the first triode pair down two paths and if you in lead mode puts them back together. Hiss is not a function of R34. I would bet if you connected a Oscope to the amp hiss would show up in the second lead stage or after the active EQ. The Re-verb CKT would also be a place to look. Hiss is after amplifying the noise floor on hi gain amps, or going over a bad resistor, which signal is not flowing over R34.
the Legacy is a nice sounding amp, but the lower input Independence is not stopping it from having hiss, as when you crank the gain there is some hiss to it.