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??
Hi Sutts- I haven't tried the KR845's, but the US NOS 845s were a huge improvement over the stock Sino tube. Yes, they are expensive. However, considering their longevity and the level of sonic improvement, I believe they are a worthwhile investment. Enjoy.
Jcb- longetivity??!! I had heard that this is where the 845's are NOT as good as some other tubes- i.e. KR themselves just this afternoon quoted me ~ 3,000 hours max for the 845 tube... That is a big concern as the system is used for HT & 2-ch, and I often have the amps on like 6-7 hours per day.
Remember the KR 845 tubes use an oxide-coated filament, not thoriated tungsten, which is what vintage 845s and chinese ones use. (Bright emitter vs. dull emitter)...

personally, yes - I think the vintage ones are worth the $. Let us know your impression of the KR ones if you get a chance,
Hi Sutts. I have both the ASL-1009dt and the 1006dt and have the amperex 845's,rca 845's,centron 845's,and the chineese valve art 845's.My overall preference was the amperex copper based 845... however I did not find them significantly better than the valve art. The chineese 845 is a very good sounding valve by comparison and an extrordinary value when you take the cost into consideration.Regarding their life expectancy...I am not sure? However the NOS 845's should last you a life time....I can tell you that I have over 1000 hours on a pair of chineese valve arts without a single hiccup.Perhaps the other contributer was using them in a different 845 based amp.In the ASL 1009 amps...just stick with the chineese 845's and enjoy, as they are simply "fabulous" sounding amps with most speakers. Further more:the driver tubes have a way bigger influence on the overall performance! Cheers David
Ecclectique- thanks for the response- the biggest influence I have found so far is the input/phase split tube upgrade- went with a quad matched pair of Mullard 12au7's- fantastic! OK, I will stick with the stock 845's- my guru buddy (Israel Blume at Coincident) concurs, saying that the 845 upgrade will not prove all that substantial of a change, and is cost prohibitive...
Hey Sutts.Which vintage mullard? I found all the mullards great..but my favorite mullard is the box plate 8139.Retains that mullard tone in the mids with better resolution in the bass.If you are into tube have to try a 60's Mazda chrome plate 12au7.They can be a little hard to find but there are lots out there with a little searching and usually quite reasonable to boot.They are easily identified by their silver plates,a lot of them are labelled GE made in France.In the 1009...they have all the body of the mullards with better top to bottom balance.I found the mullards a little rolled on the top when compared to the telefunkens,siemens or mazdas.The chrome plates have that beautiful soul of the mullards with the top end air and resolution of the teles.Really opens up the window on the stage! A great compliment for the 845. Cheers David.
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...
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.
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 wants for them).

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).
Kr845's need to be used in the right amp. You cant just automaticly put it in any 845 amp. Once you get that ok'd, i found it very, very good. Easily betters the 845b and 845m. A much more sophisticated tube sonically. Some of the kr reliability issues can be attributed to poor application. Of course a good tube cant make a bad system sound amazing!So, to answer the original question, absolutely, yes they can.