A question about valves.

[mjw]

I haven't owned much valve stuff over the years but I do own a valve phono stage (Tron Convergence). It suddenly occurred to me that valves have a finite lifespan and I'm not sure what happens next. In that, how does valve failure usually (or always) manifest itself? Do they just stop working or can it be more dramatic?
Thanks for reading.

[Arkless Electronics]

It varies hugely. Valve wear is something that happens very gradually, often to the extent that eventually you just get a feeling that "I'm sure it used to sound better than this....". If wear gets to an extreme level, distortion and/or low output would often be apparent.

Of course there are other failure modes besides wear and sometimes you will get a "cold failure" where the heater goes open circuit and the valve doesn't glow. Obviously this is not gradual! Other times a valve may just become noisy or microphonic to the extent that you want to replace it.

Spectacular failures are mainly seen with output valves in power amps. This link may be of interest http://theartofsound.net/forum/showthread.php?41279-Valve-Question&p=698214#post698214

[Boyse6748]

Well, phono stage valves usually have a longer life span than amplifier valves.... probably in the order if 10's of thousand hours.

Usually, valves will become noisy and fail sometime later (never happened to me) but if you are into tube rolling there are many valves that you may wish to try, instead of the stock valves.

Psvane are incredible but quite expensive as are other NOS stock (Mullard s etc).

For now, if it's working ok and sounds ok, leave well alone.

Peter



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[Arkless Electronics]

Well, phono stage valves usually have a longer life span than amplifier valves.... probably in the order if 10's of thousand hours.

Usually, valves will become noisy and fail sometime later (never happened to me) but if you are into tube rolling there are many valves that you may wish to try, instead of the stock valves.

Psvane are incredible but quite expensive as are other NOS stock (Mullard s etc).

For now, if it's working ok and sounds ok, leave well alone.

Peter



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Phono stages are amplifiers and there would be no particular difference between life of valves in either. Output valves in power amps will usually be the quickest to wear out. Sometimes valves will wear out quicker due to the way they are used (how hard they are being run) and some valves have reputations for wearing out/failing quicker than others... 10,000 hours would be good going and is often the spec given to long life special quality valves... which is not to say a standard quality valve cannot last this long, just that it is not specified to last this long by the manufacturer.

[Boyse6748]

I stand corrected to a more experienced guru. (Only based my assumptions on what I have encountered.) Strike that last message. I bow to experience!!!!!


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[topoxforddoc]

I haven't owned much valve stuff over the years but I do own a valve phono stage (Tron Convergence). It suddenly occurred to me that valves have a finite lifespan and I'm not sure what happens next. In that, how does valve failure usually (or always) manifest itself? Do they just stop working or can it be more dramatic?
Thanks for reading.

Michael,

You could always email Graham Tricker at TRON and ask him directly. The lifespan of valves depends a lot on the circuit design and how hard the valves are driven. As he designed it and chose the valves for your unit, he is best placed to help.

Charlie

[mjw]

Thanks, all. I've probably got what I need now. I just had no idea what might happen. As you all know, the valves on this unit are hidden so I'll continue to enjoy it until a change is apparent.
I've read about tube rolling and faffing isn't really my thing - I'm more music than equipment (and have no real idea what type's in there right now, other than it's three valves).

Charlie, I emailed GT before I bought the unit and he was as helpful as you suggest on questions of longevity, where I could buy replacements etc. I just never thought to ask about the symptoms of failure. Digressing totally, I see you're located at Cheltenham and I'm pleased to tell you that you're getting a new neighbour. Our lad James graduated this summer and has secured a job at UCAS. He moves into a new house-share at Pitville this Saturday so be sure to give any skinny, ginger lads a kindly wave if you see one as you pass through the town.

[topoxforddoc]

Charlie, Digressing totally, I see you're located at Cheltenham and I'm pleased to tell you that you're getting a new neighbour. Our lad James graduated this summer and has secured a job at UCAS. He moves into a new house-share at Pitville this Saturday so be sure to give any skinny, ginger lads a kindly wave if you see one as you pass through the town.

I hope he enjoys Cheltenham. It'll only be a short walk from his house to work :)