New to tubes

A pre-amp with KT-88's?! Are you sure about that? Those ain't no
preamp tubes my friend!

Usually when preamp tubes get old and weary you'll start to hear some
weird noises coming from your system in the form of pops, cracklin' and
scratchy kinds of sounds...I think they named a breakfast cereal after
failed preamp tubes didn't they? I think most of the small pre-amp
(6922, 12AX7, etc) tubes have a lifespan of between 5,000-10,000
hours depending on the tube and brand. You can also purchase a tube-
tester, or bring them to a friend with a tester, or service joint with one
and have'em tested out.

Marco

Wow Marco, I didn't mean to stress you out: three postings :). Not sure about the KT88's. Could it be EC 88's? Does the type of tube matter for the lifespan? Maybe a tubestester is a good idea, although I might be a little paranoid, since the tubes installed are about half a year old, and I even have the original ones (which were replaced for better sounding ones, according to the seller). Is a tubetester easy to get hold of? And how much would such a beast cost?

Nah, no stress here. Just a funky connection to the internet or bad browser. I cleaned up the mess before you replied (phew). It was hangin' up on me and I didn't think it posted after five minutes. Yeah, you have ECC88's which are the same as 6922's. Lifespan is rated at around 10,000 hours tops, depending on the pre. You know if that's the only piece of tube gear you own I wouldn't go the bucks for a tester (you can find them for anywhere from around $100-300 on average I'd guess). They are one of the more common and coveted tube-types, and also one of the most counterfitted as they can command a high price on the NOS market. Buy from a reputable seller. At 10,000 hours a pair of tubes is likely to last you 3-5 years of listening say 6-8 hours a day. So if you just make a note to replace them every three years, or when you start hearing the rice crispie dudes inside your rig, you can avoid the cost of a tester. If you want a tester they come up here and on eBay...you may have to get the one you buy calibrated though. I use a BK707 and it serves me well. There are others that do an excellent job, but do make sure they test your tube type(s).

Marco

Thanx for the reply. May I bother you with another question, not about tubes this time? My poweramp is a real class A-device, and runs extremely hot. To the best of my knowledge, this should shorten the lifespan of the transistors (Sanken). I have the opportunity to buy a couple of them, but on the other hand, the amp is working (extremely) fine, so maybe I'm just wasting money, and I know zillions of ways to waste money in ways that will provide me with instant pleasures... Any input (not on instant pleasures though) would be appreciated.

Satch
Tube Pre and Class A ss power amp-I really like that idea .
Keep it simple change the tubes every 2 years,cost on 6922/EC88 minimal.I agree 5000 to 10000 hours life span.Try some different brands,fun to do.NOS is good but beware paying to much.I am using Siemens CCa's in my Pathos Logos,works nicely!
Enjoy
Chris