Recorded Cleaning Machnies

Thanks, that was most useful! 

I have both an isonic and a degritter.  They work at different frequencies-the degritter at 120KHz and the isonic at 35Khz.  The higher the frequency the better the cavitation in the groove-so a cleaner record where it counts.  If cleaning more than 3-4 discs at a time, the cavitation isn't strong enough to completely clean the disc.  Neil Antinn has commented on this many times.  I think both are good machines and I use both, the isonic as an intermediary step and the DeGritter as a final distilled water and ethanol rinse.  If I had to choose one, it would be the degritter all day long.

I'll add a few things. First, I started using an ultrasonic machine to clean records when the Audio Desk original model came out. I found that it did a nice job on well preserved and new records but if you buy older copies, or have copies with a questionable cleaning history, you need to use a manual cleaning method (combined with vacuum) to clean some deeply contaminated records effectively-- that ultrasonic alone won't do it despite the convenience, lack of physical contact with the groove surface, etc. 

I also found that a lot of the problems with "used" records probably resulted from previous "bad" cleanings- sprays, wipes, etc. This form of contamination is essentially the residue of cleaning agents that were not effectively removed from the record. 

Third, and think Neil addresses this, the number of records in a given bath, spacing, location of transducers and the ultrasonic machine's power in relation to the bath size all factor in to  effectiveness of the ultrasonic process; there is some science to this and its also understandable when you consider how cavitation works: waves creating imploding bubbles. The implosions are what cleans.

A machine that does ten records at a time is not necessarily going to clean more effectively than one that only does a single or double LP at a time; it could be less effective, though it sounds more convenient. This can all be calculated.

You also have to consider whether you are going to use chemistry; it will enhance the cavitation effect by reducing the surface tension of the bath water, but you also have to remove the chemical residue once done. This takes us full circle to my comment about past bad cleanings. 

I'm sure Neil (@antinn) can correct anything I mistook above; I don't have the science or engineering chops but arrived at a lot of these conclusions through experimentation. And, I'm happy to say that I published Neil's book, Precision Aqueous Cleaning of Vinyl Records, and in the course of doing so, learned a hell of a lot about why certain things work and others are less effective or cause problems. 

I am thinking of buying an ultrasonic. Can anyone tell me an approximate number, percentage of records that need "contact washing" vs ultrasonic washing? 

And would I be able to tell by looking at the record if ultrasonic will suffice?

I was first under the impression that a regular clearer/vacuum machine would do a good enough job for MOST of my records but now it may be the other way, I'd be better off with an ultrasonic? 

@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.