Tube myths


Many have asked me the same question, "How does the tube sound?" Well, the sound of the tube, is affected by numerous factors, such as circuit interaction, voltage applied to the tube, system setup, use of the tube, etc. All these things, combine, to make the sonics that one's hears, in his system. A bright sounding tube, in a mellow system, will appear to sound neutral. A tube that accentuates, the presence region, in a room with a dip, in that same region, will sound neutral. A neutral sounding tube, in a etched sounding system, will pass the etched sound along, and appear to sound etched. See what I am getting at? It's very hard, to know how a tube will sound, to the end user, in his/her room, and his/her system, based on how it sounds, in yours.
Different tube manufacturers, had a "house sound", whereas the tubes, they manufactured, tended to follow. But to what degree, the end user, will hear this sound, is solely influenced, by the various factors.
Another question frequently asked, "Is the tube NOS?" Manufacturers published a "spec sheet", that listed a set of parameters, that determined, a NOS(New Old Stock) tube. In order to determine if a tube meets this specification, one must determine, the test conditions, and invariably, test for voltage gain(emission). The voltage applied to the tube, must meet the manufacturers specs, to determine, if the emissions, are what the manufacturers specified. The NOS spec, is 99% of the time, lower, than the actual emissions, of a true NOS tube. A true NOS, unused tube, tested, according to the manufacturers spec, will almost always exceed the NOS spec, by approx 10%. A tube with an emission reading of 100%, tested accordingly, usually indicates, some use. However small, it is still used. Not knowing the history, of the tube, it takes, a true emission tester, that the applied voltage, can be varied, and a working knowledge(experience) to determine, to any truthful degree, that a tube is NOS. Mutual conductance testing, is a great way to match tubes(except power tubes), but is very unreliable, in ascertaining, whether a tube is NOS. The cosmetic condition(the way a tube looks) means nothing, as far as to whether it is NOS.
I will periodically, post more info, on the various, tube myths, that are floating around the web. My best advice, is to find a tube dealer, who is willing to stand 100%, behind his products, and knowledgeable, about the product, they are offering.
fletchj
This is a discussion forum, not a place to advertise.

I do not disagree with the information you have provided regarding tubes and dealers. What I take exception to is your stance that you are doing this as service to your fellow hobbyist. When you initiate a post promoting yourself as a knowledgeable, caring provider of NOS tubes, you are advertising.
Herman, there was no reference to myself, as anything. I did not even state, what my experience, with tubes are, nor for that matter, what experience I have. I only stated, what one should look for. Everything else, you have assumed, is based on what is going on, in your mind, what you inferred, not what was stated. If you agree, that a knowledgeable, and dependable dealer is important, then we are in agreement. I am not advertising myself, I am simply stating, what I think, about tube myths. That is what this forum, is for.
OK, let's examine the facts, no inferences or assumptions.

1. Fletchj is a dealer in NOS tubes
2. Fletchj posts detailed information on NOS tubes setting himself up as being knowledgeable about these tubes
3. Fletchj advises us to buy only from knowlegeable dealers

Dictionary.com defines advertise as "To make public announcement of, especially to proclaim the qualities or advantages of (a product or business) so as to increase sales"

Wordsmyth.net says it is "to present (a product or idea) in a favorable light to win public patronage, support, or approval."

I have no way of discerning your intentions, so I will accept that you did not intend this as an advertisment. However, whether intentional or not, you placed an ad.
When one offers information, one should be knowledgeable about the information, one is offering. Think aboutit, if a doctor told someone, that they should visit a doctor, for an ailment, they were suffering from, is he advertising himself, or offering, what he thinks, is pertinent information?
Your analogy is flawed.

How will a doctor know someone is ill unless that person contacts the doctor for advice?

If that same doctor goes onto some public forum and proclaims that they are an expert in some field of medicine, then they are advertising by any definition of the word you choose to use. Just, like, you, did.

Evidently you are unwilling or unable to grasp this simple concept so I am wasting my time. I wish you the best of luck in your endeavor to sell NOS tubes. If you wish to continue to use this forum to advertise your expertise and solicit new business, and Audiogon is willing to allow it, then I suppose that is between you and them and I will butt out.