Slow valves have been discussed before, and from the responses the main things I have seen to check for are
- obstructions, due to either a mechanical defect or dirt or other foreign matter in the valve
- playing technique
- valve oil considerations (too much, too little, wrong chemistry)
- some combinations of the above which by themselves might not be a problem
- an overly tight valve tolerance (sometimes resolved by lapping, even using toothpaste etc)
Anyway, I thought I had my occasional slow valve problems licked by keeping the trumpet as clean as can be, not eating before playing, and using the best matching oil for that trumpet (one of La Tromba T2, Ultra Pure and Hetman's Light #1) but despite that I'm stumped right now with my recent '41 Committee acquisition which has developed a slow 2nd valve return when playing certain passages. This was not a problem before that I noticed, but has developed since getting the old badly flaking lacquer replaced.
Can anybody point me to the sure-fire technique they use to improve valve response, other than giving it to a tech?