Vacuum Record Cleaner Rreplacement

@richardbrand 

I do query your rule-of-thumb factor of three.  I set my ultrasonic bath level so the bath is a bit below the level of the label.  Records are vertical in the bath, so the inner part of the grooves get less than a third of a turn in the bath, depending on where the actual recording stops.

You are correct. The factor of three is just an approximation.

Do you have any observations showing the influence of cleaning temperature?

Higher temperatures do improve the ultrasonic cleaning efficiency for some contaminates. However because vinyl records can begin to warp at ~45 degrees C, it is recommended to keep the bath temperature below 40 degrees C. I typically operated my ultrasonic bath at ~35 degrees C. 

Instead of relying upon microscopic or submicroscopic examination to determine whether or what amount of US can damage the information in the grooves, I would look at the frequency response before and after.  To do that, one would require a test LP with a series of frequencies encoded in separate bands, say 100Hz, 500Hz, 1000Hz, 5kHz, and 10kHz. Take two copies of such a test LP and test them for response at the indicated frequencies, using an oscilloscope or other sensitive instrument.  You could normalize to 1000Hz; in other words, set the 1000Hz response to 0db.  Do this for both LPs in advance, so you know about any inherent differences in amplitude of the responses between the two LPs in advance of any treatment. Then take one LP and clean it with US.  Then test both LPs for frequency response again, using the untreated LP as a control.  This could get very complex, as one would want to test several different US conditions, including an extreme case that you know in advance is likely to do damage.  If such a test LP exists, that would be an interesting study. (In practice, one would probably think of more internal controls, but I think I have the main ones here.)

@richardbrand @ljgerens Re temperature and warping, yes, they star warping above 40C. However, after a few minutes the warping equalizes and the records are back in their original state. Done that countless times at 45–50C. Initially it looks scary, but soon after all is back in OG shape. No re-warping when taking them out of bath, vac, and air dry. So it seems to be caused by partial contact of record with warm water that induces the warping. Once entire record is at same temperature, no warping. Sort of makes sense.

@lewm Yes, use US machine with RO water (TDS of around 70). Re RO vs distilled water rinse, I have not done either. My observation is when listening to record with no rinse, just vacuum the cleaning fluid off and hearing nothing except music. No surface noise, no pops, no clicks, just nothing. I trust my ears here. Less than no noise is impossible, so no need to add any further steps if I already arrive at zero noise.

Absolutely agree, there are many way to skin that cat. Enjoy your taxidermy!

@oberoniaomnia 

I am curious why you are running your ultrasonic cleaner at 45 to 50 degrees C temperature. When we did our study we found no statistical difference in cleaning efficiency with bath temperature between 25 to 45 degrees C. The only reason to operate at a higher temperature would be to be at your surfactants CMC minimum. Warpage is certainly a concern at these temperatures but you seem to have no issue with it. The bigger concern is elevated temperatures and/or excess ultrasonic exposures will accelerate the migration of additives from the bulk to the surface. We have observed this on our record test samples as well as on numerous other polymeric materials. Some of these additives (plasticizers in particular) will form a sticky, tacky residue in the record grooves. This sticky residue is difficult to remove. If not removed, this sticky residue will attract airborne dust and dirt and create a gummy residue on the stylus when the record is played.