AlexcThe B&K will not apply operating voltages, to the tubes. So at the 240v? it applies, everything is fine. But the amp applies operating voltage to the tubes, so at 470v?, the tubes show problems. Gs5556 Now you know to ask, not just is it tested, but how was it tested, what voltage, what the manufacturers spec, etc. This will give you a much better chance, of getting the most useful answers. Maxcast Welcome to the wonderful world of tubes. Above all, trust your ears!
Tube Myths- Tested Tubes
By the many emails, thanking me for the info, I have decided, to not let criticism, of my supposed intentions, stop me from posting, information.
Almost all customers, of mine, asked if a tube, has been tested. Most ask for the best testing tube, thinking, that it would mean, that it is , the best tube, as far as longevity, sonics, noise, etc. Testing tubes, will tell you, whether a tube, is within specs. It will give you a reading, that you can correllate, with the manufacturers specs, to determine if a tube, is good, and useable, or defective. It will not tell you, how good a tube, will sound. It will not tell you, how long a tube, will last. Noise testing, will not guarentee, that a tube, will not be noisy, as some circuits, place demands, on tubes, that no amount of testing, can predict, how they will act. Don't get me wrong, testing is invalueable, because it narrows the field, and gives the user, a much better chance, of a tube, that will meet their needs. It just not a carte blanche guarentee, that a better testing tube,ie; balanced sections,emissions, will be a better tube. Because a tube, tests higher, will not mean, that it will have a longer service life, than one that tests lower.
There are many tests, that a tube can be subjected to. The more testing, that is done, the better chance, of predicting, how the tube, will act. But none can tell you, how it will sound. That can only be determined, by the tube, being placed in the intended circuit, allowed to breakin, and listened to. And because circuits, run tubes differently, it's difficult to determine, that operation, in one circuit, verifies the same operation, in another. For instance, a tube operated at 240v, might be just fine, but at 310v, it shows some problems. Or a tube at 290v, is perfect, but at 210v, it exhibits problems. In a perfect world, it would be just fine, throughout it's entire operating range, but this is the tube world, we live in. Enjoy.
Almost all customers, of mine, asked if a tube, has been tested. Most ask for the best testing tube, thinking, that it would mean, that it is , the best tube, as far as longevity, sonics, noise, etc. Testing tubes, will tell you, whether a tube, is within specs. It will give you a reading, that you can correllate, with the manufacturers specs, to determine if a tube, is good, and useable, or defective. It will not tell you, how good a tube, will sound. It will not tell you, how long a tube, will last. Noise testing, will not guarentee, that a tube, will not be noisy, as some circuits, place demands, on tubes, that no amount of testing, can predict, how they will act. Don't get me wrong, testing is invalueable, because it narrows the field, and gives the user, a much better chance, of a tube, that will meet their needs. It just not a carte blanche guarentee, that a better testing tube,ie; balanced sections,emissions, will be a better tube. Because a tube, tests higher, will not mean, that it will have a longer service life, than one that tests lower.
There are many tests, that a tube can be subjected to. The more testing, that is done, the better chance, of predicting, how the tube, will act. But none can tell you, how it will sound. That can only be determined, by the tube, being placed in the intended circuit, allowed to breakin, and listened to. And because circuits, run tubes differently, it's difficult to determine, that operation, in one circuit, verifies the same operation, in another. For instance, a tube operated at 240v, might be just fine, but at 310v, it shows some problems. Or a tube at 290v, is perfect, but at 210v, it exhibits problems. In a perfect world, it would be just fine, throughout it's entire operating range, but this is the tube world, we live in. Enjoy.