Audible Illusions hiss


My AI Mod 3 has noticeable hiss in both channels. It does not get louder as the gain is increased and is not present when the mute button is on. It also does not matter which source is selected.

Someone said the tubes in these can make a big difference. Does anyone have any experience in this area? Thanks.
128x128wynnosu
Many years ago I bought an Audible Illusions Modulus 2B (or was it 2D). Anyway, I used it sparingly for several years, until it developed a hiss similar to what you described. I liked the preamp but traded it in on a Classe DR6, and the hissing sound was gone. Just my two cents!
Thanks to everyone for your input. Sounds like the unit needs a checkup and, probably, different tubes.
@wynnosu. It's been a while since this thread was active. I have an exact same problem that you mentioned in this thread. Did the noise go away after you replaced tubes. Did you do anything else? Thanks.