Are the better $$$ 845 tubes worth it sonically??


I have the ASL 1009 monoblocks (a pair of 845's per amp), and have the stock Chinese 845 tubes. Has anyone compared their 845-based amps with ANY other type of 845 tubes?

I am most interested in hearing about the KR 845's, as they are current production, and available from Czech at $430/matched pair . The older GE-type NOS 845's seem way to expensive.

I guess the main question though is WHAT differences sonically did you notice upon using a 'better' 845 tube, and was it worth it??
sutts
Hi Sutts, how is everything?

If Jcbtubes recommends something, TAKE IT TO THE BANK!!!
Trelja- what's up guy? Jcb didn't get back to the thread when I asked about NOS 845 tube longevity- I may contact him about this...

Ecclectique (I like that moniker a lot btw!)- I am happy with the Mullards I have, but am unsure of exact vintage and don't want to go too crazy searching out exotic 12au7's, as I need 4 of them at a shot and these amps are on with HT & 2-ch sometimes 8-10 hours per day, and at that rate will be burning through NOS tubes faster than I would like...
12au7's will last thousands of hours, and they are cheap - don't worry about it. get the best you can find and enjoy them. life is too short to worry about it otherwise. Vintage 845s can last as long or longer than chinese, I think. I have probably 1000+ hours on a pair of Cetrons right now and they are as strong as day 1. Vintage 845s were guaranteed for military use (read: extreme, at times) at usually 1000 hours. Often times of course they ran far longer than that. several thousand hours would not be unheard of. I have some 1006-845 amps, I think they run @ 900v or so around 85ma - not overly hard on the tubes. if the 1009s' run them similarly, I'd expect quite a long number of hours from a pair of vintage ones.

The difference with vintage 845s, while perhaps subtle (to some), is definitely there. Value/worth depends on every individual's situation. To me, they are worth it. With some work, they can be found for relatively reasonable money. (read: about 1/2 or less than what tubeworld.com wants for them).

thanks
-Ed
Hey Sutts. That is over 3000 hours /year. Now I understand your inquiry regarding nos 845 tube life. The good thing is: the nos 845,s are said to be good for 20-30,000 hours.Regarding the current KR 845...Who the hell knows? I haven't even heard the new 845- however, I must say that I am very impressed with the sound of the 300bxl and 842.Hopefully; someone that uses the kr 845 will jump into the thread and comment.Regarding the 12au7's.... The tubes that I recommended should cost you a lot less than the mullard 12au7 and if you should happen across any perhaps you might consider them for down the road.Like most nos preamp tubes.... they ain't getting any cheaper! Cheers David.
Thanks guys- great comments. Re: the KR 845's, KR said ~ 3,000 hours. I am CERTAINLY not going to pay the $1,700 CDN that our local Canadian distributor wants for the quad set I would need to have them last only a bit over 1 year...

However, Ecclectique, your comment is interesting- 20-30,000 hours??!! I can't believe that! Wow- if that IS the case, hey, sign me up!! Which NOS tubes are the ones with this incredibly ling life?? (and yes, I have also had the KR 300BXLS in a pair of 300B monoblocks- they are great tubes).

Also- where do you FIND these super long lasting and superior NOS 845 tubes for NOT a small fortune? (I would need 4 minimum).