Thumbs up for ultrasonic record cleaning

As a follow up, directions I'm considering:

*80kHz tank since I use it as the 2nd stage and 80kHz process is more penetrating but gentler
*slower motor; anyone knows of a cheap 1/3rpm or so motors in EU? 230V synchro would be the best
*submicron filter - are carbon filters good? would they not filter out also the chemical solution out of the water?

I’ve been following this thread for some time now, very interesting reading and thanks to all the contributors.

Some observations:
I owned one of the original AD US cleaners and was not impressed with the results or the build quality. I replaced it with a KLAudio KD-CLN-LP200 with (IMO) much better build quality, but still unimpressive results. I’ve looked at the DIY machines and have been reading everything I can get my hands on wrt to US technology. There seems to be a considerable difference between low frequency US cleaners (28kHz) and higher frequency (80-100kHz), the former used primarily as industrial cleaners (car parts, large metal components etc), the latter used for more delicate structures, especially fine jewelry. The cleaning action is created by the collapse of the cavitation bubbles which can create extremely high pressure (10’s of Mpa) and high temps (5000°C), but on a very small scale, determined by the size of the bubbles: The lower the frequency, the larger the bubbles and the more concentrated the released energy. On high power, low frequency US machines, this process can be so aggressive the sides of the stainless steel tank are subject to etching.

I was curious about this, so I did some measurements on my KLAudio RCM which is assumed to be 40kHz. It actually runs at 34.72kHz which would seem to be more aggressive, almost midway between 28 and 40kHz. There was a frequency adjustment pot, and I monitored the AC power being consumed as I adjusted the pot. Increasing the frequency lowered the power consumption and lowering it increased the power; at 33kHz, it went from 200W to almost 350W. The power consumption also changed drastically between running the cleaner with and without a record (200W with vs 150W without) indicating that the load seen by the transducers affect power consumption and the load changes with mass, density and distance from transducers.

So my question is this: With so many variables affecting the performance and operating parameters of the US process (temp, surface tension, power, frequency, cavitation efficiency), how does one know what they are really getting and what they are doing to the record surface (not only whether it is effectively being cleaned, but whether it is being damaged in the process)?

@dgarretson Very interesting observation re 38 vs 80kHz! Have you made some systematic research on it? There is quite some discussion re frequency going on. You input would be very valuable.

At the moment I'm afraid to go past 35C and 15mins. If I have a Lp I can sacrifice, I'd try.

gbanderhoos

I replaced it with a KLAudio KD-CLN-LP200 with (IMO) much better build quality, but still unimpressive results ...

That’s interesting. I’ve had outstanding results with the Klaudio. It may not be the best device for extremely dirty LPs such as you might find at a yard sale. For them, I think the right fluid and a vacuum machine might be the best first step. But for everything else it works very well, imo. What could be more impressive than a pristine clean disc?

... how does one know what they are really doing to the record surface (not only whether it is effectively being cleaned, but whether it is being damaged in the process)?

If the record looks clean, and the phono cartridge stylus is clean after playing the LP, I’m satisfied that the US cleaner was effective. Because LPs almost always sound better after a cycle through the Klaudio, I can’t imagine how the cleaner could have caused damage in any way. The few LPs I’ve heard that may not sound better after being cleaned in the Klaudio were clean to start with. They sound about the same after a pass through the Klaudio.