If they're starting to get noisy they're probably about done. Kind of a rushing slurry sound. By the time they make static they're getting close to failure I think.
Upscale I think still has British surplus Mullards. I bought two sets of the 12AT7s years ago for a VTA ST70. I'm still on the first set.
I agree, if you're using it for a home theater pass through you stack up the hours fast. I've gone through sets of 6922s in ARC preamps in a couple of years that way.
Upscale I think still has British surplus Mullards. I bought two sets of the 12AT7s years ago for a VTA ST70. I'm still on the first set.
I agree, if you're using it for a home theater pass through you stack up the hours fast. I've gone through sets of 6922s in ARC preamps in a couple of years that way.