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Do tube amplifiers improve with age?

I have McIntosh mc901 mono amplifiers connected to b&w 802D3 speakers. and a CJ gat2 preamplifier, which is part of the home theater signal chain. i use transparent super ultra premium plus speaker cables - frankly I don't remember exactly what they are but they were kind of expensive.

I'm finding my amplifier seems to have improved with age and may be getting even better since I bought it a couple years ago. I use stock tubes because I don't trust nos anymore. I tried telefunken small NOS tubes but then a few of them went bad so I went back to the stock JJ tubes. And they sound fine. The amplifier specs say 901 amps dont have any distortion to speak of so maybe that's why changing out tubes doesn't really matter that much. The biamp experience is marvelous.

I'm wondering in light of above does a tube amplifier improve with age? Maybe I should replace the power tubes at some point but they don't seem in need of replacement but maybe things will get even better if replaced. 

Maybe Jay was unhappy with me because I was disappointed he doesn't take interest in tube amplifiers, and no I owned my 901 before he even understood the functionality as he bought them when his speakers didn't have biamp capability.  Remember?

 

emergingsoul
mlsstl
1,597 posts
 

Tubes deteriorate with time. Running current through the filament wears it out, rather like a car engine or tires wearing out as the miles pile on. You might get 2,000 hours out of a power tube and maybe 10,000 from a preamp tube but a lot of that depends on the design, your use, and luck. Another issue is matched tubes may not age at the same pace making them mismatched. Finally tube amps run at high voltages which is tough on components, especially capacitors. 

I have a fondness for tube amps but I've never thought they improve as the years pile on.

larryi
4,642 posts
 

I doubt that they do; you are probably the one improving in your appreciation.  What they do is not deteriorate as fast as so many seem to think that they do (the caps need replacement after 15 years crowd).

I should be hoping that they do improve as my amp is made with critical parts that are now more than 70 years old.

knotscott's avatar
knotscott
1,414 posts
 

Some tubes sound better to me after a few dozen hours, but after that they're constantly degrading.  Other than some of the caps burning in for the first 100 hours or so, I can't think of why the amps might improve.

mlsstl
1,597 posts
 

@larryi Tubes and caps typically aren't perfect one day and bad the next. Sudden failures can happen but its not the more common way that they need replacement. So they do fade away over time. A power tube with 1,500 hours on it isn't as good as a new one. I spent years building and rebuilding tube amps and kept a tube tester around to keep an eye on things. You could watch them age.

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