Some pre-amps require rugged tubes. My SP10II is one, your AI is another. Many, probably most, popular tubes suffer early death (get noisy) in these units. Often 100 hours or less. I use NOS 6h23. They will work well in your AI. Not a 'warm' tube - fairly neutral. FWIW.
Bad Tube in an Audible Illusion M3A
After using an Audible Illusion M3A preamp for over three years I finally had a tube go bad. I noticed a loud whoosh in the right channel and traced it to the phono section. By swapping the tubes between left and right I discovered it was the tube on the right side causing the noise. The tube had only about 300 hours on it.
I've had tubes that I replaced because the highs diminished, I have a tube in an amp that rattles when it powers up, but I've never had a tube get noisy. Why does a tube do this? It would seem the tube would short out or just stop working.
In hindsight I shouldn't complain, this is the first tube I've had go bad in the M3A!
I've had tubes that I replaced because the highs diminished, I have a tube in an amp that rattles when it powers up, but I've never had a tube get noisy. Why does a tube do this? It would seem the tube would short out or just stop working.
In hindsight I shouldn't complain, this is the first tube I've had go bad in the M3A!