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AUDIO FORUMS >> General Discussion and Support >> Do loud levels kill power tubes faster?
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Message started by canonken on 10/31/20 at 21:26:53

Title: Do loud levels kill power tubes faster?
Post by canonken on 10/31/20 at 21:26:53

I'm sure different amps have different designs, so specifically lets say in the context of Decware EL84 amps.

If you are playing music at lower levels (say 1/10th of a watt) vs. higher levels (not clipping, distorting, but using all of the power available) - will the tubes wear out faster, or are they 'burning' at the same rate no matter what you are doing?

I believe when you start talking about things like guitar amps where you are purposely over-driving the tubes, that will kill them faster, but that is probably not going to be happening in a audio enthusiast setting!

Title: Re: Do loud levels kill power tubes faster?
Post by hdrider on 10/31/20 at 22:26:40

Canonken - My experience with tube home audio gear is that running gear hard doesn't hurt tubes much if at all. I never listen to levels that the amp is clipping, besides it just sound crappy that way. However tube amps for my bass in a live environment got more rough treatment by roadies than volume. Those tubes got changed out way more often than my home gear anyway. When I had my 2watt Zen amp it wasn't driven into clipping very often and with the Rachael now I would say never.

Title: Re: Do loud levels kill power tubes faster?
Post by canonken on 10/31/20 at 23:13:01

Thanks.

For something like the UFO amps. Does turning up the volume/increasing output actually increase the voltage/current/heat going to the tube, or is the tube in its full-power state as soon as its powered on, and you are just using more or less of the available output capacity?

I 'think' a Class A (solid state) amp is like what I described. Always running at 'max' and you are just using more or less of what is there.

Title: Re: Do loud levels kill power tubes faster?
Post by GroovySauce on 11/01/20 at 13:12:55

My basic understanding is if the tube is in normal operating parameters, it's putting off the same amount of power. The grid controls if that power is being passed or not.

Said another way. Tubes are also called valves. The same amount of pressure is always on one side. Depending on how much the valve opens, controls how much pressure comes out.

I really these type of videos about tubes. there are a bunch!

https://www.youtube.com/watch?v=lIUIGdC0Tag&t=642s

Title: Re: Do loud levels kill power tubes faster?
Post by canonken on 11/01/20 at 15:28:11

That makes sense.

Usually when I think of increasing the output, that comes with increasing voltage, current to the output device. Otherwise...where is the extra power coming from!? And the answer could be 100% of the power is there all the time, and you just modulate it to anything lower you want.

Bonus question - if you start to hear clipping/distortion, does that mean you are actually hurting the tubes, or does it just sound bad? I understand on SS amps, clipping is bad, especially as it relates to speaker drivers (and tweeters being most at-risk).

Title: Re: Do loud levels kill power tubes faster?
Post by HockessinKid on 11/01/20 at 15:30:17

Volume should not affect a tubes lifespan. Setting the bias too high will shorten a power tubes life. There are numerous sources which provide setting ranges for different power tubes, depending on their plate voltage and power.

HK