@tima,
@bazelio,
@marty:
Make no mistake, that the powerful UT tanks that are used being used for record cleaning can damage a record. I recently assisted someone who was using an Elmasonic P60 with temperatures as high as 50C with a Vinylstack spinner at about 0.15-rpm, and at least one record was damaged. The record surface took on a dull, mottled finish. Now there was no subjective audible damage but without comparison to a new record that could be debatable.
Now in this case, four factors were in play - the high power of the Elmasonic, the 37kHz which with power can damage surfaces (with the power of the Elmasonic and 37kHz - it could pit gold), the high temperature and the very slow spin speed.
When people try to compare other uses of UT to UT for record cleaning, very often the comparison is not applicable. Always remember, there is the power needed for onset of cavitation, which is not that much, and then there is cavitation intensity which is power dependent. Cleaning jewelry is easy and does not need a lot of UT power and given the nature of the substrate that is metallic or jewels that are relatively soft, you definitely do not want a lot of power - it will pit the surface. Additionally, the surfaces do not want to hold on to detritus like a record does.
The record is a rather odd beast to clean. The stylus can produce an audible response equal to a displacement of less than 1-micron, and trying to remove particles and films this and smaller is not easy. And this is complicated by the material (the substrate) that has these wild properties - first its plastic which wants to hold on to all forms of detritus - this isn't Teflon, its elastic - it's not rigid like metal so it can deform under high cavitation intensity, and it has this crazy looking groove with side wall ridges - it's like trying to clean the Grand Canyon.
So, on first glance the record appears pretty simple, but dive deeper and it becomes quite a challenge to clean it well enough to recover all the music it can reproduce with mostly absent any crackly background.
Ultimately the devil is in the details.
Take care,
Neil