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burned out el-84?


wpkg

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Hey

 

quick question out of curiosity: have any of you burned out or destroyed the el-84 in your VJr (or any amp for that matter)

 

I know we adjust the bias to get the voltages right, but a close friend whose opinions and advice I totally respect restores vintage tube audio hi-fi gear as well as guitar amps and has done so for years. he knows tons about tubes. he says the el-84 can be pushed quite far past its recommended plate voltage.

 

So... without debating too much about whether or not he is right, (cause I don't know if he is right) have any of you ever burned out an el-84?

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Not sure exactly what your asking? By burned out do you mean biased too hot to the point of failure....or simply burned out as in used up tube? I've had several el-84 based amps and with heavy use on some of them I'd only get 6 months out of a set of power tubes. On my valve jr's I havent had a tube fail,but I've been swapping tubes around quite a bit to be honest and haven't pushed them all that hard for 3 or 4 nights a week.

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couple of things comes to mind, the vj is an single ended amp which means the tube is running 100% all the time; I doubt that the audio file amp's us an SE design. So in a push-pull amp they're only on 50% of the time; I could see the life of a tube being a lot longer.

Audio file type amp's you want to run clean not dirty like guitar amps so there to would probably make for a higher bias.

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couple of things comes to mind' date=' the vj is an single ended amp which means the tube is running 100% all the time; I doubt that the audio file amp's us an SE design. So in a push-pull amp they're only on 50% of the time; I could see the life of a tube being a lot longer.

Audio file type amp's you want to run clean not dirty like guitar amps so there to would probably make for a higher bias.[/quote']

 

could be... he made mention of a few designs he had seen where the el-84 was running 100 volts hotter than what they are spec'd for, and worked fine for the normal life of the tube. i will have to ask him more about that.

 

Layboomo, either but more specifically if you have left your VJr stock and noticed that the output tubes life was much shorter than it should have been (since you mention you have had a few el84 amps)

 

this is all just curiosity, i for one think it IS a good idea to tame the voltages down from stock, as i did not hear any difference when I did that, so why not?

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could be... he made mention of a few designs he had seen where the el-84 was running 100 volts hotter than what they are spec'd for' date=' and worked fine for the normal life of the tube. i will have to ask him more about that.

 

Layboomo, either but more specifically if you have left your VJr stock and noticed that the output tubes life was much shorter than it should have been (since you mention you have had a few el84 amps)

 

this is all just curiosity, i for one think it IS a good idea to tame the voltages down from stock, as i did not hear any difference when I did that, so why not?[/quote']

 

 

Yes with a stock Valve Jr I would expect short tube life without adjusting r-10 and r-14.....one of the reasons they put sovteks in IMHO...they are pretty rugged tubes....not the best sounding but very forgiving. I have my suspicions thats why they fused the tube heaters as well.....thats not done by many amp manufacturers that I know of. Ask your friend about that in the HIFI world.

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