Although not exactly related to the topic, it would be helpful for any Air Force user to know the effect of increasing the volume of air reserviors.
I have tried to add one litre lab bottles to my AF1P. The air pressures used in Air Force both in vacuum and float are fairly small. There is no worry that the pressure is too high to break the glass. It is perfectly safe.
My impression was increase the air volume would soften the sound. The difference is not small, very noticeable. So as the diameter of the tube, using a bigger tube will have the same effect as increasing the bottle volume. The designer, Hishikawa san, said he has tried different tubes and different air volume and the current setting the best he could find. So one can regard the system was tuned to the designer preference, but that doesn't stop users to, at least, try different volumes to see if the sound suits them more.
Air Force users should try this addition in their system. It is very safe, completely reversible, does not harm your turntable and it is cheap but is good fun.
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