2. amps-preamps
  3. 1209864603

pre-amp unacceptable noise level?

How much is an unacceptable level of noise/humming etc. from a pre-amp? I just bought a new tube pre-amp and when I replaced my old solid state one with it the noise level from the speakers practically tripled. There is an audible humming from the listening chair 10ft. away. I can't say I'm particularly happy with this considering the one I replaced did not do this.
fruff1976
rkny
47 posts
 
My Rowland 102 amp introduced a major hum into my setup. Turned out to be the cable TV. A Jensen Ground Loop Isolator fixed me right up.
fruff1976 OP
103 posts
 
I don't have t.v. hooked up into it. It's just a 2 channel rig with a cd player and I haven't hooked up my turntable yet.
prpixel
876 posts
 
Bad tube? Did you bias the tubes?
fruff1976 OP
103 posts
 
Not sure how to bias tubes? This is my first tube pre-amp. Also, after hooking up my old solid state pre amp I noticed the system noise I'm talking about is present, but not as loud as with the rogue. Is it possible the noise is originating in my power amp and is being amplified to a greater degree with the rogue?
sugarbrie
3,854 posts
 
You do not need to bias the tubes with preamps.
The cheater plug would go on the power amp, if that is the problem.
Is it both channels or one? If one, you might have a bad cable.
If the hum is there with both preamps, then it is not the Rogue.
Tube preamps are usually not as quiet as solid state, but is would be the normal hiss sound that would be louder, not a hum.
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