Recorded Cleaning Machnies

@whart, 

Bill what you said is correct.  To amplify, Industry testing has shown that for low kHz machines (< than about 60-kHz), if the flow in the tank is >50% of the tank-volume/min the cavitation intensity drops off very quickly.  As the record spins through the bath, it essentially creates flow, and the book has a calculation that considers the number of records and the rpm, and based on one or other, determines the max rpm or max # of records.  However, there is a minimum rpm recommended of about 0.5-rpm otherwise depending on the UT tank power, the record may be damaged.  Even with the inexpensive Chinese UT tanks, which may not produce advertised power, the bottom of the record is very close to the bottom mounted transducers where the cavitation intensity will be highest.  

@gano, 

Basic rule of thumb for using a single UT tank, is that for best results and best bath management, you want the record to be visually clean before UT cleaning.  So, for a new record, do a simple quick brush with a soft brush to remove visual surface debris, and then into the UT tank.  For used records, you want to perform a pre-clean step before final UT clean, and that can be performed with your process of choice be it a SpinClean or vacuum-RCM.  

@antinn Thanks, Neil.

@gano - the answer is that proportion of older copies that have been contaminated. Visually, you may not see this. I was buying a considerable number of "rare" records and in some cases, particular pressings,  that were either not often seen for sale (even before the Great Disappearance™) or quickly went up to astronomical pricing. Therefore, I tried like the devil to get them to a high playing state. (Though in a few cases, I did wind up with multiple copies to get one that was a good, quiet player). 

I’d say there is a direct correlation between how many old pressings you buy and how often you have to resort to more rigorous manual cleaning. In some cases, I bought records that were never played, just bounced around among dealers, some of whom didn’t know what they had. Those days are over and I’ve slowed down considerably on buying, given grade and price inflation. Some are simply not on the market given the limited number of original pressings that were made, private label or obscure things that never succeeded in the market place at the time of release. There is no good answer to your question. Every record here gets cleaned before it gets played, including new records which for me, is a small fraction of what I have. But I vary how I approach each and also use a Furutech DF-2 flattener-- once you are sensitive to warped records, you’ll see how many are; I won’t flatten something that tracks properly but if the record is out of round, there’s not much you can do. Perhaps digitize it and rely on that-- I know that goes against the grain of the analog purists (of which I was once one), but I don’t want to risk my cantilever, especially on a linear arm where you can see the arm "hunting" on an out of round copy. 

PS: FWIW, if I had to choose between a vacuum machine and an ultrasonic, I'd opt for my Monks Omni, which is not a casual purchase. But, thankfully, I don't have to make that choice; I use both methods and they are synergistic in a real sense. 

It's been my experience that US cleaners perform best when cleaning one lp at a time. 

Neil and Bill have it right: you can't tell by looking, and some combination of mechanical cleaning and ultrasonic cleaning is needed for older records. Maybe if one only bought new records an U/S machine alone would suffice, but I can't see why anyone would limit themselves to only new LPs!

Having said that, any cleaning is better than none, and even a simple vacuum machine will give you most of the auditory gains. When you see the minutiae of cleaning solutions, kHz and KW discussed, we are in the territory of diminishing returns. Those smaller gains may be very important to some, but you can have 80-90% of cleaning benefits just by doing it at all, by whatever means.

@whart, @antinn

Thank you! 

I should have added:

I mostly buy very old, very used records. I wont use two machines, two processes. Not because I don’t believe in it, I just know I would not have the energy, I would a put a record after I bought it in the machine and then I would have little reason to do it again as I do my best to keep them away from dirt. I also don’t have the budget and space for two items (barely for one). I want to buy the one that does most of the job. Sounds like the vacuum based would be it. The ultrasonic does the final, smaller portion. Maybe I am very wrong in understanding it. 

So Pro-ject or HummingGuru?