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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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Tubes Asylum Questions about tubes and gear that glows. FAQ |
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In Reply to: EL509 / Sovtek 6PI45C posted by billanichols on September 9, 2003 at 19:42:55:
Yes, I've had the same thing happen. I bought a batch of 17 Svetlana 6pi45C valves about a year ago for my DIY T8 monoblocks and so far 4 valves have failed. 1 was DOA (grid short), 2 failed after a couple of hours use, 1 failed after a couple of weeks use and after the amps had been on for about 24 hours one day. In all failure cases (except the grid short) the getter flash was gone and when I examined the valves there was a crack across the base.Infant mortality with these valves is apparently well known, and I was advised to expect 20-25% initial failure rate. I suspect that there is an inherent weakness in the design and/or manufacturing process which makes them susceptable to heat stress on the base of the valve.
I never noticed any audible signs of this approaching, either. They just suddenly fail, which backs up the idea that it's not an internal structure problem, but heat related - the glass cracks, gas gets in and the valve is useless.
To be fair, I've used the amps for about 2,000 hours since I built them and 6 of the original 8 valves I installed are still in there, sounding great and showing no signs of any problem. Seems like if the 6pi45C is going to fail at all it will be in the first few hours of use.
Cheers
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Follow Ups
- Re: EL509 / Sovtek 6PI45C - TG 20:55:25 09/09/03 (1)
- Re: EL509 / Sovtek 6PI45C - billanichols 20:36:03 09/10/03 (0)
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