Tube reliability in amps

drjjpdc, you inquired about tube life - thats easy stuff. there are just too many varibles involved in answering your question re biasing of any particular tube absent a specific application and i am not a resource on the tube amp market.in my opinion you are much better served not being concerned with the life expectancy of tubes but by finding an amp which will sound good with your speakers. after going thru some arc and sonic frontiers amps i settled on a mesa baron - its a fairly powerful and neutral amp using 6L6's biased at 38ma. i have speakers by paragon which are full range and very neutral which are rated 86dba @1watt. using a power stage w/120wpc and a little neg feedback i get the kind of sound i want, however someone with speakers tilted up in the midrange, or high end, would hate it. this is not a testimonial to mesa - the point is you sould consider auditioning push/pull pentode based tube amps with your speakers to find the sould you like. once found you won't care how long the tubes last. cj, arc, vac, cary, sonic frontiers, are all good high end amps to try. if you want to start out on the cheap just to experience the tube sound there is much available and talked about in this and the audio asylum forums.

I B&W Matrix 802S3's.....they sound GREAT with my ARC VT100 MKII which you can pick up used for about $2500. Don't fall for the "you have to use SS" BS, at least not with your speakers .....& unless you find a SS amp you really like.

I have N804s and am about to go tube as well. From this and the Audio Asylum forum, I have found that at least my N804s will be alright with 100wpc tube amps for loud hard rock, and around 50wpc for jazz and vocals at good volume levels. Two reasonably priced tube amps float my boat at this time. The Cary V12 which can do 100wpc ultra linear and 50wpc triod at the flip of some switches ($4000 retail new) The other is the VAC PA 100/100 which does 100wpc. I have seen the VAC used here for $1800-2500 and the Cary used at $2500. There are other choices. My Cary SLP 2002 pre will arive this week . Present amp is a BelCanto EVo 200.2.

I am currently running the BC21/BC22 combo from Blue Circle and am very happy with it. Since I got this setup two months ago it's been turned on constantly. The sound is much better when I leave them on all the time. I really haven't worried much about tube life since only the BC21 preamp has two tubes and the BC22 amp is solid state. However, I just received an e-mail from Blue Circle warning me against this practice. Aside from the lightning strike consequences, they feel many of the citcuits will suffer for it and it robs tube life. They suggest a 15 minute warm up period before each listening session.

Hi, I agree w/the posters who mentioned ARC power amps for having long tube life. Both of my ARC amps use 6550's; ARC gives a very conservative estimate of 1500 hrs on these power tubes but I and other owners have found much longer life. My VT100 Mk 3 uses 6H30 supertubes for drivers, rather than 6922's as the older VT100's do, and the 6H30's are rated for 10,000+ hours. BAT gear also uses the new 6H30's w/this very long tube life. But again, these are driver tubes and they tend to last longer anyway. My ARC gear need matched quads of 6550's, so keep a spare single around just in case one tube goes bad and you have a good one to test with. About B&W 804's w/tubes: there is a guy selling his Matrix 804's and his Anthem tube amp on this site right now, I would email him about his experience running the 804's with tubes. I think 100 tube watts would be fine w/these speakers, but I haven't heard them for myself.