Tube question

As far as how often tubes have to be replaced depends on how you use your equipment. I leave my tube amps and preamp on 24/7. My tube amps are 4 watts so heat is not a major concern.

I replace the whole preamp set three times a year at a cost of about $45 per set; (2)12AX7 (2) 12AU7 and (1) 6922. I use Ei Yugo's, East German RFT's and Russian Military 6922's. (FYI - the Russian Military 6922's equal the performance of the (much) more expensive NOS Telefunken/Siemens/Amperex; I have listened to them all).

The tubes in my amps get replaced about once a year at about $150 per set; (2) 2A3's (NOS RCA's), (2) 5692 or 6SN7 and (2) 5Y3's.

The reason I leave them on all the time is because tubes sound better after they have warmed up for 48 hours. Just my preference - and the way I chose to spend money. I keep a stockpile in case a tube fails earlier than expected.

Rule of thumb: figure 2,000 hour life span for tubes.

...just to qualify my statement - the Russian MilSpec/Ei Yugo/RFT's are better sounding in my CAT MKII preamp (and associated equipment and room) than ANY other tube combo. Nothing against the NOS tubes, just happens to be that way in my gear where the extra expense is not justified. Also, CATs eat up tubes faster than most tubed gear (CAT recommends replacement after 2000 hours or whenever the sound degrades).