2. amps-preamps
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Reliability issue - Nagra VPA power not KR tube

I have a pair of Nagra VPA Type I on evaluation. I ran over the weekend. The chassis heated up to well over finger warm. Tubes are obviously very hot - 535 F. My friend that has had a pair for 4 years recently had a major issuethat costed him $ 2,000 to repair. As part of my evalution, I am curios to hear from other VPA owners, what reliability issues they have had and the costs to repair them. Are these amps one should avoid from a reliability point of view. Thanks
dcaudio
elberoth2's avatar
elberoth2
1,223 posts
 
I have VPAs, but they are on dealer loan, so I can not really speak about reliability issues from my expirience. However, a close friend of mine is running VPAs for more than 2 years now, first with chinese tubes, and now with KR tubes and only once had a tube failure (the KR one) which was replaced by Nagra for free. Apart from that tube - no issues.
sns
3,005 posts
 
I can't speak to reliability issues of Nagra, but I've also experienced KR 845 tube failure after only aprox. 100 hours on my Art Audio Carissa Signature. Now use TJ Fullmusic.
tangram
18 posts
 
i have had my VPA now for 3 yrs they have balanced and single ended inputs so they are the newer type, i have tried the valve art tubes and found them too coarse. Iam now using the very latest 845m with superb results, shying away from the KR tubes, i have had no problems at all with the amps, these are for keeps they are absolutely superb with my nagra plp preamp.There has been some issues using the KR tubes and i believe Nagra have stopped using them as they have shorted out various VPAs. I guess no matter what make of amps etc you go for someone would report some kind of reliability issues.
jjwa
69 posts
 
I'm not sure about the reliability but I can talk about the sound. I had ARC VT100 MKIII and recently upgraded to the VPA's. NO COMPARISON! The VPA's will breath life to your recordings....recreates the recording space.
I bought used on the ...GON, was so impressed that I exchanged for new at full price! I'm still using the stock tubes but have ordered the 845M. Tangram what differences did you notice with the 845M please?
linkoping
112 posts
 
in term of 845 tubes, I've tried 3 different pair in my system (Mastersound Reference 845/Italian). I tried the new 845M and was totally disapointed by the sound. Then I switched to Fullmusic 845 ($820 for quad) and got disapointed as well.
My current setup is using Valve Art, which I'm very satisfy with the sound. However, these Valve Art are getting to old so time for replacement. I just recently ordered 4 845tube from KR, let's see what's the result!
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