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Listening for tube degradation

Hey, just wondering what specifically there is to listen for in regards to tube degradation. I don't have access to test equipment so I have to rely on my ear to determine if certain tubes are on their last legs. I've been able to notice a definite "scratching" or muddied sound whenever one or more of the tubes are in need of replacement. However, I find myself replacing ALL of the tubes since I can never pinpoint which exact tube or tubes needs replacing. Also, are there any visual cues to look for (ie.output tubes glowing brighter than others)? I have a 15W integrated tube amp that you can look at on my system page.
hitman_hifi

Showing 2 responses by newbee

newbee
4,751 posts
 
Treat your tubed components just like you do your car. Simply put them on a maintenance schedule and routinely replace the tubes accordingly. I replace power tubes at about 2000 hours. This takes care of incurring a serious loss of sonics, or major shorts, due to age. I replace my small tubes, depending on use, about every 4000 hours.

Some may consider this early, but at least I don't worry about subtle degredation in the sound quality. Why invest all that money in audio stuff and then cheap out on the tubes by seeing how long they will last

Oh, power tubes lose bias as they age and you will find that you need to increase bias (ma's) as the tube ages. If you let them age enuf you will be unable to get the up to recommended bias settings.

Small tubes can get noisy and or dullish, i.e. loss of detail with age! I replace them all at the same time if it is a noise issue related to age to retain good channel balance.

FWIW.
newbee
4,751 posts
 
I 'work', when I actually do, out of my home. I turn my 'casual' system on at about 7AM and turn it off at about 4PM every weekday. So, on this system, I change my power tubes in my amp at least once a year.

I have a second 'system' (different electronics - same speakers) I use for 'serious' listening sessions, those when I'm not multi-tasking - usually at night or on weekends. In that system I've maxed out power tube performance and average about 1500 hours on the power tubes. I get to change these about every three years.

I guess I'm more than a bit wierd but I just love music and don't watch TV in my spare time. FWIW.
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