Interesting info

[bruce egnater]

http://www.guitaramplifierblueprinting.com/12ax7p2.html

It may be a few years old and things change quickly in the tube world. Just kind of interesting how different 12AX7 tubes, that should be essentially the same, can vary considerably. This is why you can't necessarily count on your results to be the same as someone else. Even is you try the same tubes, they can vary from one to the next.......so....good luck with your tube experiments.

 

[Steedee]

My questions are....
Who is driving this train? The current production tube manufacturers, or the amp manufacturers?
How can you assemble and sell thousand dollar plus amps with a possible failure rate of 30% because of tubes?

Current production tubes are the only thing I know of in all of electronics that can fail within 6 months and it's accepted by the consumer as "thats the way it is", but nobody knows why............ Are there not enough middle men for quality control?
Are the prices for current production tubes too cheap? Would higher prices produce a significant leap in quality?
What we have right now just doesn't make sense.

 

[bruce egnater]

The amp manufacturers are at the mercy of the tube suppliers. The way we deal with this is test, test and retest the tubes before and during production. At Egnater we have designed and built our own tube testing system to "weed out" bad ones so they don't get to production. One thing we have no control over is the long term life/reliability. No one can predict when a tube may fail down the road....other than assume they may. This is why you should carry spare tubes, fuses, strings, spare tire, etc. etc. All tubes are mass produced in countries who are simply manufacturing a commodity and are not really so concerned with producing quality products. There are individuals like Mike Matthews at New Sensor, Tom McNeil at RubyTubes and others who are dedicated to producing quality tubes but it is no easy task. A tube is a precision assembly that requires much hand assembly so consistency in manufacturing is a challenge.

 

[Len Rabinowitz]

The amp manufacturers also have no control over what arrives at their doorstep, so to speak. If the tube guys make junk, you have to deal with that. All you can do is test, test, test, and test again. Like Mesa, you probably reject a lot of tubes, and I am sure that adds a lot of cost, time, stress levels, etc... Still it is something you don't have any control over. You play the hand your dealt. Think about how many tubes have to get manufacturede every year. It is amazing that they are as consistent as they are, not that they fail sometimes. I will also guess that modern amps put a lot more demand on them then the old ones do, so they wear out.

 

[johnsonfredral]

Today many cabinet doors and drawer fronts utilize an MDF core. Doors and drawer fronts may also be fashioned of particle board surfaced with high-pressure laminate. Natural wood offers its subtle combination of color, grain, pore pattern, variable absorption and smoothness of finish, and variation with viewing angle and lighting condition.

Cabinet makers

 

[Steedee]

Today many cabinet doors and drawer fronts utilize an MDF core. Doors and drawer fronts may also be fashioned of particle board surfaced with high-pressure laminate. Natural wood offers its subtle combination of color, grain, pore pattern, variable absorption and smoothness of finish, and variation with viewing angle and lighting condition.