I just ordered a new set of tubes for my EL34 SE int. and forgot about my EL84SE.
Here's the thing, the EL84 amp must have at least 1000+ hrs on all tubes (6CA4, EF86, EL84) by now. Maybe even 1500 hrs. All the tubes are Electro Harmonix. The amp still sounds dynamic. I don't think the sound quality has decreased at all.
Should I keep using them until a tube failure or buy some fresh ones?
I"m just curious because I've heard of people using amps for years and years without the need to re-tube and the tubes still test strong. And there are also amps that run tubes very hard which result in a shorter lifespan.
I wish I had a tube tester.
I've used a lot of tubes but sold many of them to a friend for his guitar amp, so I've never used a tube to the end of its life.
How do you guys determine when it's time to re-tube?