Amp tubes lifespan and usage

[Icarusfire]

Life span of a tube depends on amp "usage" And/Or how often you turn on and turn off your amp. But I need some clarification definition on the word "usage"

Because I just discovered something new, There is a dummy load on the speaker out of my amp, And It only gets hot when I actually play the guitar and gets cold when not played.

So can we make a safe assumption that tubes do not or less wear out when the amp is on but not played because amp is technically not "used"? If so I can leave my amp open for long time and don't worry about tube life.

Or the word "usage" directly correlates to how much leave your amp "on" but then why dummy load does not get hot when not played?

P.s My marshall amp has no stand-by, just on-off

 

[Gearjoneser]

Re: Amp tubes lifespan and usage

No. Any time it's not in standby mode, it's causing tube wear. And when it's ON and sitting idle, it's actually worse than if it's being played. In non technical terms, the tubes are creating heat, and it's not dissipating the way it does when the current is charging through the tube.

That's why most tube amp manuals tell you to turn it on standby when not in use.

You didn't mention which amp you have. A lot of small wattage amps don't have a standby switch, because small tubes take less time to heat up. But you should just turn it off when you're not going to play for more than 20 minutes.

If it's a solid state Marshall with a tube preamp, it doesn't matter much at all. Just turn it on and off as if it's a radio.

 

[Icarusfire]

Re: Amp tubes lifespan and usage

And when it's ON and sitting idle, it's actually worse than if it's being played.

Tnx, That's interesting, do you have any resources on this?

I have Marshall Dsl5c all tube 5 watt amp with NO standby. You prefer trade off time around 20 minutes, And some say around 2 hours, because they claim turn on-off the amp will also cause a wear in tubes..

 

[zzmoore]

Re: Amp tubes lifespan and usage

The tubes wear More when you play.
It is the current draw that causes tube degradation...not High Voltage. Just one more reason an SB Switch is not needed.
When you turn up the volume and play, the tubes draw more current than they do at idle. That is what wears the Cathode Coating that eventually sees the tube loose its...sound, punch, tone, etc.
That, and turning the filaments on and off.

Watts = Power = Heat.....just like the motor in your car. The more work it does, the hotter it gets.
Which is why red-plating is bad, and can ruin the tubes in a hurry.