Hi Ntscdan; I keep my SF Line 2 in standby when not in use, and I found out the hard way when to replace it's tubes. After a year or so of use, the sound (music) becomes harder, brighter, more "brittle", and fatiquing-- but this happens gradually-- at least with the Sovtek 6922s. When I finally realized what was happening and replaced them with a new set, it was like having a new pre-amp. Now I replace them every 12 months or so. Cheers. Craig
How can you tell when tubes are shot?
I have an ARC REF1 and ARC REF Phono Preamp as well as assorted solid state gear. I leave everything on 24/7 and am wondering if the tubes just quit working (ie: get really noisy) or whether there is a gradual decline in their performance? ARC makes recommendations on who long they should last but I have been running the REF1 steady for over 18 months and haven't noticed anything.