Tube reliability in amps

the life of a tube is like a tank of gas. there is a finite amount which is determined most greatly by how much you use it and how far the amp pushed its operating envelope in making the amp (read how much bias required - the more bias required, the shorter the life. i would expect on average that you should get at least 1500 hours on power tubes - up to about 3000 is possible. you should get at least twice as much on the driver tubes. its helpful to have an amp that lets you easily bias the tubes yourself, and if you can do this having matched pairs/quads, is not as important (look for amps with individual biasing for each tube. keeping spares around is like keeping gas in the tank - you won't have to walk.

hey newbie, instead of me calling up a whole lot of manufactuers, can you give me an idea of what is a lot or little bias on a tube, so I can hone in on the guys with longer life tube designs?

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.