 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
70.27.0.161
I put these in my Quad II's in October 2008, & two of them, each in different amps, have recently failed. Compared to the Genelex GEC's that they replaced, some of which had been in use since the 6o's (albeit not continuously), this seems a little miserly. Does anyone know what kind of service life should be expected of these tubes? The amplifiers were thoroughly checked out & brought up to spec just prior to the installation of the Gold Lions.
Follow Ups:
These are made in Russia by New Sensor. I have been re selling their tubes since more than 10 years, but I recently decided to stop with this company. You can PM me for the reason.
Problems I had myself with their KT... tubes were always related to gas. This was never immediately detected as such. When I had such tubes, they would at first show the bias go down, or hum, or have a tendency to occaisional grid shorts. And not show a problem on the "gas test" with any of the tube testers I have, and getter was looking good still.
That is why I always say, any getterology is for the birds. A bad tube often has a good getter. Just, a really bad getter is white or half-eaten, but long before that happens, the tube malfunctions while the getter looks nice still. So a nice getter often means nothing.
I threw all the bad testing NEW SENSOR tubes in a box, and many came out a few years later with a white getter, showing the true cause of the problem. I still have this junk box, and more and more tubes are getting white getters.
When they start to hum after 3000 hours, it can have many causes. Like too early wear out of one tube of a pair. Or one changed it bias so much, the pair is off balance because if that. So you still have two good tubes in the pair, but no matched pair any more. Or, it is related to gas problems, like described above.
KT66 should to my opinion run much longer than 3000 hours, as this is by itself a very rugged design. With this I mean the real KT66, with the vintage shape KT66 plates. So not the modified 6L6.
I had a major dispute with them, as they refused to give incoming inspection criteria to me, which I can use to test their tubes. That was a few years ago, you can search for that on AA under the EML Moniker. I guess it's still online.
Jac
This is the top side and you can see the flashing is very good after 2400 hours.The new reissues have reddish bases.
These are my original reissues I bought in late 2007 and they have at least 2400 hours on them and they show little flashing wear.I abuse the hell out of them and I have never red plated them but came close when a cap failed in my Sargent Rayment amps but they are as strong as ever.I have plenty of vintage GEC KT66s,some NIB and the rest testing close to new but most everyone of them I had to secure the lose bases which is so common on the KT66s with a top mounted plate structure.I NEVER had to do this on the reissue Genelex at anytime.
"KT66 should to my opinion run much longer than 3000 hours, as this is by itself a very rugged design. With this I mean the real KT66, with the vintage shape KT66 plates. So not the modified 6L6"
While some tubes do that,the Genelex is not one of them..I know they had a brief issue which has been corrected but you know,that stands to reason when you build as many tubes as they do.
There is no tube that is infallible to failure.Much of the tube failures I have found lately were due to dirty or loose socket pins or not being correctly biased.With SED gone,the only octal tube makers left are New Sensor,JJ,and Shuguang and maybe a couple small ones like PSvane.
Honest amplification is better than excessive 2nd order distortion anytime.
Does that mean your website is out of date? You have 'PL' tubes listed but is this a new batch of tubes or just old pages? Just curious.
big j.
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
Thank you all for your replies, & your welcome. The Gold Lion reissues have only been used in matched quads. The failure in each case manifested as an audible hum; in both cases the getters remain shiny. I estimate they were used over 3000 hours, so I guess that explains it? (Maybe I need a few more quads of other tubes to swap & so extend the lives of all of them...)
The problem is,you are assuming that the failure of the tubes was due to the tubes themselves and that isn't necessarily the case.I have my first quad of KT66 reissues I bought in 2007 and they are still going as strong as ever.I own a lot of the vintage Genelex/GECs and they are fine tubes but they also have a problem with loose bases and this is even on the ones that have never been installed.The reissues have not suffered that problem at all.I just thought I would mention that.
I want to say tho when you made these comparisons,it sounds as tho from your statement that you are mixing the reissues with some of the originals.That is ok to do only if you can adjust the bias to balance the tubes out to where they will draw the same amount of current to work in conjunction with each other.These are cathode biased amps so it will be difficult to do that.Even tho you had two tubes that failed,you also have two that survived quite well.
You also had mentioned that the GECs were not continuously used so to be fair,you would have to know how many hours are on each tube..
Bottom line,don't mix output tubes unless you can adjust the bias,or know for sure that your tubes draw the same amount of current at a given plate voltage. Welcome to our forum.
Honest amplification is better than excessive 2nd order distortion anytime.
Edits: 04/17/14
Did they go gassy (white getter) on you?
I bought a pair, and one went gassy in about a month, and the other one soon followed.
Paul
There was a brief problem with what you are describing but that was due to the supplier issue and that was corrected.
Honest amplification is better than excessive 2nd order distortion anytime.
2008 was over 5 years ago, that would be on par with many old stock power tubes. It depends how much use they get - it is more a number of hours thing. But if you use the tubes a typical amount that is really very good life. Some power tubes last forever - my Ei KT-90s are going on 11 years! But that's the exception, not the rule, and I don't put the hours on them that some other guys do.
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
