Another D'Yquem Tube Failure
 

I am very unhappy to report I experienced another 300b tube failure several days ago with my Shindo D'Yquem amplifiers.
This is my second pair of brand new amps to cause a tube failure. My first pair caused a tube failure the second time I switched them on last November. The amp was sent back to my dealer and tubes were replaced and the amp was re-biased and returned back to me. After a few days the same 300b tube failed again.

It was decided that a new pair would be ordered to replace these and my dealer would send my original amps to Japan for repair.

My new pair were delivered last December and have worked fine until a couple of days ago when exactly the same tube started glowing bright red on turn on and failed within a minute.

Very strange to have so many tube failures in such a short period of time. JH has been responsive and thinks it is simply faulty Gold Lion tubes. If so, I must be the lottery winner of bad tubes to have so many brand new tubes fail.

Not sure what the issue is but my experience so far with this model of amp has been less than stellar. When they work, the amp is amazing. Unfortunately for me the dependability has left me doubting whether I want to continue using these in my system.

The irony is my dealer is now sending me my original repaired amps back to use temporarily until we decide how to resolve the problem. Hopefully they will arrive next week.

J.J. Sorry to hear this; I hope they can figure out what is the cause of these failures.

Hi JJ- Just an fyi and of course I'm very sorry for the trouble- your first pair was not repaired, they were sent to Japan for a full check out and found to only have a bad Gold Lion 300B. So for the record and clarity on the forum, none of the amps ever failed, several tubes have failed. The amps didn't cause tube failures, the tube manufacturing caused the failures. The tubes are run rather conservatively as in all Shindo designs. Its unfortunate as these Gold Lion tubes sound fantastic and so far most are holding up well. My pair has been my most used amps since they arrived and must have over a thousand hours with no issues. As I mentioned to you in our emails, it could be a production run tube issue or just that tube lottery. We'll take care of you. Jonathan

Thanks Ivan. I hope so too.

JJ , I'm sorry to hear that as well. I remember you told me about it too. I had same kind of problem with my first MC275 in first 4 months. Now it works fine for last 2 years. Hopefully everything works out well. Coz I have my eyes on your amp too for my speakers :)

The 300b tube has had a long history of premature tube failure. Check out the posts of individuals who have paid extremely high prices for WE tubes to only have them fail after 6 months. I personally think the Siemens F2a is a better tube, certainly more reliable rated at 50,000 hours. Try to find a rating for tube life of a 300b????

My first ones failed at less than 2 hours. Seconds at about 6 hours. Thirds at about 300 hours. Very frustrating. I am thinking of giving up on these amps and tubes as it is difficult to to deal with failure when you don't have a Shindo dealer nearby.

It maybe an amp issue. Only ten of these have been produced. It's possible that the power on parallel SET Shindo amps has yet to be be perfected. Who knows. What I do know is I have no music. Very disappointing.

JJ, sorry to read this.
I have GL 300B's in my Manley preamp. About 50 hours of use and they sound stellar.

Some info interesting : JC Verdier considers JJ tubes ( made for you JJ ! :D ) to be the most reliable on earth today.
Nagra uses them in their 300B amp that sounds stunning. Why not using them in the D'Yquem's ?

The original Western Electric 300B -until 1988- is known to last 40,000 hours under ideal conditions, one of the most reliable tubes in history. The F2a is also extremely reliable and can compete with WE 300B's in longevity. To say the 300B is known for premature failures is a new piece of info to me. I would say very strongly that this is not the case. Sadly, original WE 300B tubes are very expensive and no longer available in any quantities.


As for the new production Gold lion tubes, I have no idea. 500-600 hours on this current set is certainly premature for one to fail. I would hope for 2-3000 hours from a modern 300B at a minimum before any failures.


Several things can affect tube longevity in an amplifier- high a/c line voltage and/or surges, poor ventilation, vibration, tube operating points, transformer/speaker load, tube manufacturing quality and mechanical contacts within the socket. In my mind, the only way an amp itself, without human error, can cause premature tube failure would be high operating points or poor contacts. This is certainly not the case with the D'Yquem. The tubes are running quite comfortably in both plate voltage, current as well as filament voltage. Shindo Laboratory has been producing commercial 300B amps since 1981.


Human error is generally the faults we see- Using low impedance or low efficiency speakers, improper ventilation, tube rolling without biasing, flipping the power on and off without allowing the amp to cool down, strong vibrations due to poor racks or floor placement, not using Switchcraft terminated light weight interconnect cables etc


In your set up with the tube cages off, being on a heavy piece of wooden furniture and connected to a mild speaker load, it seems it can only be the Gold Lion tubes. Whether its a production run issue or just the way these tubes are, I do not know. Many new production tubes have good runs and bad. I have asked Shindo for their thoughts.


It would also be interesting to know the line voltage. If this rises significantly, even for short periods, the tube plate voltage and current rise with it. A power tube failure could be the result. Preamp and driver tubes wouldn't be affected by this. Years ago, pre Tone/Shindo, we had a client that had an amp that failed repeatedly. We measured his line voltage and found he had 133V! A power transformer multiplies the incoming voltage. 1V in can result in 2-3V out to the power supply of the amplifier. 13V over could have been 40 V of overage in the circuit. Thats an extreme case and would not expect your line to be over 120V. However, only way to know is to measure. My line has gone from 119V pre Hurricane Sandy to 112V post Hurricane Sandy and most recently with new lines run in my neighborhood, to exactly 120V.


That being said- tubes fail. They will always fail. Sometimes prematurely and sometimes not. Its totally unpredictable. A tube swap, bias adjustment and you are back in business. Its frustrating to be without music but all is easily resolved with a multimeter, screwdriver and a spare tube.


While certainly more than 10 pairs have been made so far, this is a Shindo amp. Production numbers are always low. These are hand made, one at a time.

Jonathan

Hi NOL',

Ha, when I read your experience-and chagrin!--shades of Moi in perplexy at something like that happening -while not resident in the US when I had slight problem with my previous Shindo Amp JH came to the fore and facilitated the prompt fix and return from the factory.

Rest assured all will be well in no time for your treasured unit

Good Listening,

Des