How are tubes to be purchased in general?


I have never had a tube power amp. Although I have a tube preamp (AI3) it is relatively unfussy with tubes. If a power amp has a matched quad set of tubes, how do you replace them if only one goes bad? Most are sold in matched pairs. How many do I have to keep around for emergencies? Do all four ever go bad at once, or can I just pop in one or two. I talked to the manufacturer (Rogue) but the rosy picture of tubes lasting years finds me a little bit skeptical. Of course if this question is like an owner of a gas guzzler car wondering if he can afford the gas (tube replacements) please tell me so or to go get a SS amp. It's just that a cheap pair of matched KT88's/6550 go for about $70.00 new, two monoblocks mean 8 tubes so that is $280.00 investment.
drjjpdc

Showing 1 response by clueless

Agree with the posts above. Nice to measure the voltage (bias) running in your tubes - get a meter. The only time you are going to run into trouble is if your tubes are running hot and some amps change over time. Not like Sand amps where you plug them in and never think again for 10 years. Get to a local club or post on the audioasylum.com tube section. Someone will have your amp and will be able to tell you just how to take readings and what they should be. I think you will find the audioasylum site invaluable if you are new to tubes.
Good Listening!