Do valves wear out in time?

robgilmo

Ive heard they do, however I have an old Revox tape player from the 60's with the original valves in it, runs and sounds lovely.


So whats the story guys?


I have a Vox Cambridge amp, apparently its got a valve in it, do these need changing out as preventative maintenance? Do they wear out and degrade over time?

olafgarten

It depends on how much it's used, the Cambridge just has a preamp tube in channel 2 and that can last between 200 and 500 hours usually.

robgilmo

Ah, Ok, I have no idea how many hours are on it, when they eventually die do they take any components down with them?

ICBM

Old-production valves run correctly according to the design spec - as things like the Revox will do - can last for several thousand hours or more.

Modern valves often don't last as long, and most guitar amps run the power valves too hot (especially EL84s for some reason), which is where the idea that valves wear out quickly comes from.

It's quite normal to find vintage non-guitar equipment like that Revox with its original valves working fine.

The Cambridge should probably be OK too, since the valve is a preamp one - but if it starts to sound quiet, dull or noisy it might be worth seeing if a new one improves it.

It's very unusual for failing preamp valves to damage the surrounding parts, although power valves certainly can do.

robgilmo

I cant fault the amp, although it does sound quite cold but I just thought that's what Vox amp sound like, so probably best leaving it alone. It is noisy if I turn the volume up to say 3 o'clock with no signal through it but that's not really an issue as it never gets turned up that loud anyway.    

57Deluxe

I think I saw an Horizon prog about this at some stage...