How to tell when power tubes need to be replaced?

[cmalak]

esteban...you can run an experiment tonight. Play some music for about an hour or so without the lamps on and then play the same rotation of music with lamps on for the next hour and see if you get the deterioration you mentioned a few nights ago. If yes, then simple solution is keep lamps off or audition a power conditioner and see if that improves the overall sound of your system (and protects against line fluctuations).

[cstmar01]

Good information regarding it all.

I'm sort of in the same boat. Using tube amps and never had them before and just always fear when a tube might go. Been almost thinking of getting a tube tester to check on things but don't know yet. I know tubes can last for awhile and I check the bias on them every time I play and nothing has change so far.

I think if I upgrade to a different amp I either will have to do some that auto bias and have default sensor on it or a SS that sounds like a tube amp.

[rlw3]

I told Kevin Deal of upscale audio i was going to track tube usage hours with a hand tally clicker. He said his way was to ocassionally sub in a new(previousily broken in) for the old let it settle in then listen. If the difference is great chuck the old, if not use the old tubes some more.

[sanji]

One way to tell if your tubes are approaching replacement is to take remove them and inspect the silver coating by the getter. As tubes get older, you will see that the silver coating will either disappear or become lighter. Compare with a new tube and you will clearly see the difference.

[AMatters]

+1 ^

[weapherge]

Hey guys. Couple of questions. For you guys that play metal with a V4, what are the highest gain tubes avialable. I have a master volume add on mod that sounds good when the preamp is cranked to 10 and MV leveled off to listenable volumes. I realize the gain comes from the preamp tubes so I want to know which you like best.

Also, when playing with an overdrive pedal with the master volume cranked and preamp on lower the power amp tubes pulse blue. I read thats normal. But the tube in space 3 doesnt pulse blue on heavy playing. It glows though. Any thoughts?

Thanks

[jdandy]

weapherge.......Welcome to Audio Aficionado.

It sounds as though you are asking a question related to a tube based guitar amplifier. Is this correct? I don't want you to feel neglected if no one answers, but you will probably find answers to your questions by contacting the amp manufacturer.

[Jerome W]

Originally Posted by jdandy

Esteban.......I am not familiar with the Prima Luna Dialogue One amplifier, so I am only offering general advice. It may well be one or more of your small tubes, particularly the driver tubes that provide the voltage gain that feeds your power tubes. Most power tubes will last between 3000 and 5000 hours before any sonic degradation begins to become apparent, and typically the small tubes are double those hours, but you could be experiencing an issue with the driver tubes. You should find a dealer or tech shop that has a calibrated tube tester, and have all of the tubes tested.

There is a possibility that the Prima Luna's Adaptive AutoBias circuit is misbehaving. This circuit uses a reference signal from the input voltage to adjust the bias voltage on the power tubes. There are no manual bias adjustments. If this circuit is not operating properly it will cause issues with the sound as well as with tube life.

You did not say whether you leave your amplifier on all the time or just when listening. It is a good idea to have an hour meter that comes on with your amp. Then you can accurately track the hours of use. This helps to know when you may begin to expect tube failure.

Dan,
Great post !
Where can we buy an hour meter ?

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[vintage_tube]

Here is the main EMM site which several on AA have in use.

Incase this web site is policed by the admin, do a search on ENM LCD hour meter.

T44 LCD Hour Meter | ENM Counting Instruments

Happy Holidays Folks,

Bob

[Jerome W]

Thanks Bob !

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