deadlift Posted April 26, 2017 Share Posted April 26, 2017 I frequently hear one had to give a tubes a certain period of break in time a range of hours. So I was wondering does anyone out there have a good method of tracking the actual number of hours that a tube has been in use ? Thanks Quote Link to comment Share on other sites More sharing options...
Kalifornian Posted April 26, 2017 Share Posted April 26, 2017 I would be interested to see some scientific evidence showing that there is a change in the sound coming out of a system over time as the tubes warm up. I think obviously 5 to 10 minutes to warm up but after that are there really any changes? I think more often than not it is the persons hearing that is getting accustomed to the sound.... Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted April 26, 2017 Share Posted April 26, 2017 23 minutes ago, Kalifornian said: I would be interested to see some scientific evidence showing that there is a change in the sound coming out of a system over time as the tubes warm up. I think obviously 5 to 10 minutes to warm up but after that are there really any changes? I think more often than not it is the persons hearing that is getting accustomed to the sound.... Other than the tube reaching a constant operating temp and burning of any gases that were in the tube, no additional break in. Basically, a tube is broke'in in 10-15 min. If you don't like what you are hearing then, the next 20-100 hours will do little to change it. You may grow accustom to the sound or the user needed a break'in period. 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted April 27, 2017 Share Posted April 27, 2017 Like Derrick mentions, once the tube is up to temp that should be it as far as break-in...it could depend on the tube as well. (size/type) Most vacuum tubes that are manufactured have to pass through the burn-in rack before other quality assurance testing, so it would be safe to say they are already broke-in once they leave the factory? Figure the entire tube amplifier as a whole warming to operating temperature, and how that affects the sound of the amp. A large tube amplifier with large OPTs, chokes, PS iron can take some time to warm up... Quote Link to comment Share on other sites More sharing options...
moray james Posted April 27, 2017 Share Posted April 27, 2017 When tubes are made and the getter is fired up to draw the final vacuum there is always some residual chemical left in there unburned. As the tube ages little by little over the years that chemical is burned up and that results in the tube slowly pulling a slightly better and better vacuum. Finally the day a tube dies it is sounding the best it ever did because the vacuum is at its best. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted April 27, 2017 Share Posted April 27, 2017 17 hours ago, deadlift said: I frequently hear one had to give a tubes a certain period of break in time a range of hours. So I was wondering does anyone out there have a good method of tracking the actual number of hours that a tube has been in use ? Thanks According to a paper RCA issued in '52, tubes actually do need 50-100 hours of use in-circuit for their operating parameters to fully stabilize. As to tracking that, a piece of paper and pencil should work just fine! Every time you use the equipment log how long it was on. One point about longevity which is rarely considered is the filament voltage. If it is more than 5% above rating (approx. 6.6V for the typical 6.3V tube) longevity will be reduced. I've worked on many pieces of gear which put around 7V on the filaments when furnished with the typical 120V from the wall outlet. That is not acceptable. Maynard Quote Link to comment Share on other sites More sharing options...
deadlift Posted April 27, 2017 Author Share Posted April 27, 2017 As for tubes sounding better or different after 100+ hours I'm still on the fence although I know many who firmly believe that is the case. I do know that with my current setup (Manley Neo-Classic 300B and Manley 300B SE/PP's) the first 30 minutes are less than stellar but after that everything starts to shine. That's why I usually start off with a CD and do other things, once the CD is finished then I settle down into the sweet spot and spin some vinyl. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted April 27, 2017 Share Posted April 27, 2017 12 hours ago, mike stehr said: Like Derrick mentions, once the tube is up to temp that should be it as far as break-in...it could depend on the tube as well. (size/type) Most vacuum tubes that are manufactured have to pass through the burn-in rack before other quality assurance testing, so it would be safe to say they are already broke-in once they leave the factory? Figure the entire tube amplifier as a whole warming to operating temperature, and how that affects the sound of the amp. A large tube amplifier with large OPTs, chokes, PS iron can take some time to warm up... I found the same as far as the whole amplifier warming up. My HH Scott LK-72 has large transformers that take up to several hours to FULLY heat up. As this is happening anyone can hear the amplifier is sharpening its performance. Not hard to notice by adjusting the volume up and down and listening. Gets more accurate and can play louder, cleaner as this process occurs. Just like an old car warming up. I don't agree about the tubes though. I find their sound changes as they age. Clearly for me. So I agree with Maynard on that point. By the way I also have VRDs, Peach, NBS, and McIntosh C220..............so I listen to a lot of tubes. 1 Quote Link to comment Share on other sites More sharing options...
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