Effect of Boost/Distortion pedals on Amp Tubes.

[Robusto]

A question for you experienced MESA guys/gals.

I have been keeping my eye on many posts where folks use a boost/distortion pedal in front of their amp to alter the tone or create a 'tighter' distortion. And it seems the consensus that the pedal creates a 'hotter' signal that hits the preamp tubes to accomplish this goal.

My question is this: In your experience, does that 'hotter signal' affect the life of the preamp tubes?

 

[ibanez4life SZ!]

Not in my findings....I've always pushed the front end of my amps, and never have I run into preamp tube trouble.

Would they run longer unboosted? Probably....but they still last me longer than the year that I usually run them before swapping, so works fine for me!

 

[Old BF Shred]

Basically, yes; but I would not worry about it.

Any Overdrive, Distortion or Compressor will compress the waveform of the signal. It will increase the average amplitude (amount) of the driving signal. This increases the duty cycle of the device (tube, in this case) and will increase the average amount of current through the tube. So yes, technically it could reduce the life of the tube.
But this is happening to some extent with any gain stage of any amp. Those tubes run with higher current as a result will have less life. How much less will vary with amp type, position in amp and your personal settings.

You would have to run an extreme level of drive (likely beyond what will sound musical anymore) to significantly shorten tube life. It can be done though. I once fried v1 in my Triaxis by running an FX processor at too high a level into it, but it ceased sounding good well before that point....then again, could have been coincidence. :shock:
Mind you, this was during a troubleshooting session and not normal playing circumstances.

For what most people would use these pedals for, if it sounds good, while tube life may be shortened a little bit, I would not loose sleep over it.
Good luck

 

[jdurso]

Preamp tubes can last a loooonnnngggg time, so unless you started off with a bad tube or have had the amp for a while (5+ years), you shouldnt notice much difference in the life of the tube. Is there a difference in life? of course, but you'll need to have the amp for a while before you blow a tube, on the premise that the tubes were all storng tubes.