Ultrasonic Record Cleaner 40 v 80 v 120 kHz

I think you have to back up and look at what kind of cleaning you need. I buy a lot of older pressings. They don’t clean up fully solely by use of US type cleaners. I learned that through experience. The question of frequency is a factor in choosing US machines-- the non-made for LP machines, like the Elma, can do two frequencies. Other machines can fire at different frequencies as well. These are not all the "audiophile" made for convenience machines. If you are using a surfactant, you need a way to get it off, other than blow drying.

Some, more elaborate adapted systems include two baths, one for rinsing.

I’m lazy. I clean on a big Monks Omni, then pop into a KL RCM- I do not do any chemistry on the US side.

But, depending on budget and objectives, as well as the nature of the records you buy, you should aim for what best suits your needs. I tend to buy M- older pressings. Nothing goes under the stylus before it has been cleaned and inspected (and on occasion, de-warped).

@jwr159 IMHO ultrasonic cleaners are a bad way to go. Ultrasound strong enough to clean a record will damage the vinyl. The weak ultrasound used in record cleaners does not do much, but the real problem is drying. Place a few drops of record cleaning solution on a glass slide or mirror and let it air dry. You will see a spot where the fluid was. This is what happens when a record is air or fan dried. To get a record really clean it has to be vacuum dried. There are a number of fine vacuum cleaning machines on the market. I like the Nessie. It does the job, is well made and a good value. The very best record cleaner is the Clearaudio Double Matrix Sonic Pro. It cleans both sides at the same time. You get a totally clean record in about three minutes without a drop being spilled. It is, unfortunately, more expensive than most people are willing to spend.  

I've had a DeGritter for 3 or 4 years, have cleaned hundreds of albums through it, and no vinyl has been 'damaged' - rather, it's been 'cleaned'. I don't even use record cleaning solution, just distilled water. 

I've been very pleased with my Klaudio US cleaner. Simple, one-button operation makes cleaning easy. For the rare occasion that I have a really dirty LP (such as one bought used or one that I'm cleaning for a friend), I clean it first in an original generation Nitty Gritty machine.

Neil will come and give you the low down before long. One consideration is that the size of the cavitation bubble that forms (as well as it's energy) is related to the frequency of ultrasonic vibration. 120kHz bubbles are likely to clean the bottom of a vinyl microgroove, whereas I believe 40kHz might not do such a thorough job in theory. Does that make a practical/audible difference? There's the rub, as there's a lot of money to be saved with a 40kHz machine. I have a MkI Degritter and I'm completely satisfied with it, used after a vacuum clean on a Loricraft.