Thumbs up for ultrasonic record cleaning

I've been experimenting with USC in the past few month, having cleaned about 30-40 2nd hand classical Lp's so far. I've added USC as a second stage after my regular Okki Nokki vacuum cleaning.

I must say it has not been so far such an epiphany to me as it seems to others, rather incremental. The biggest disappointment is that it does not seem to reduce clicks&pops, sometimes making them even more pronounced, probably due to quieting the background. I'm quite sensitive to clicks as I'm listening on high efficient Stax headphones, so all is in my ears.

Whats it does seem to do, provided I use right chemistry (see below), is  increase of micro and macro dynamics, and detail retrieval (so perhaps all the clicks I hear are due to permanent vinyl damage). On some LP's the sound becomes more direct which is a big plus for me.

Here is the hardware and procedures I use:

GT Sonic 6L 150W 40kHz machine + 1um filter+ 1rpm motor for rotation. I clean at most 3 Lp's at the time as evenly spaced as possible. I can clearly see the standing waves between the vinyls.
Currently I'm using 5% IPA + 0.05% Tergitol S7, which is available in Poland albeit v expensive. This Tergitol concentration is recommended by the archivists and the solution is already foaming. I was afraid to  use the higher 0.13% concentration as recommended elsewhere after my failure with PhotoFlo. I used it instead of the Tergitol and it was giving me unpleasantly "plasticky" sound despite a mandatory 2 step rinse on the vacuum machine. Had to US rinse all vinyls I cleaned with it and clean all that had contact, incl. the tank, the filter, brushes, etc.

The procedure is:
*1 step vacuum: Apply the above solution, let it soak for 5mins, biderectional scrub, vacuum.
*USC: 60% power 40kHz, 32-33C, 15mins (first degass for 10mins, filter before the batches)
*2 step vac rinse: First high purity DI water then 3% ethanol

I've once heard opinion that alcohol dries vinyl surface and one can never get rid of pops&clicks. I tried just DI water USC too but no real change and Tergitol softens the cavitation action at 40kHz, lowering the surface tension. I'm thinking of investing in a second 80kHz tank to see if the more refined cavitation would improve. Perhaps my initial vac + scrub is quite efficient in removing what's easy to remove.

Cheers,
b

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?

@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.

@whart Thank you very much for your informative input! This is similar to the process I'm currently using, but I do not rinse after the vac pre-wash since I US clean with the same solution as I vac (5% IPA + 0.05% Tergitol).
What do you use for your US cycle? Just high purity water?

@whart That's what I thought - KL discourages use of any add-ons no? Honestly, I'm sticking with alcohol just by some inertia. I like it for its grease dissolving properties. Also as far as I understand, it actually makes the 40kHz cavitation gentler by lowering  water's surface tension. Having said that, next tank solution I'm gonna try will be just water + 0.05% Tergitrol, excactly as used by the Congress Library and see if I get less clicks n pops. I also tried pure water US but I'm a bit afraid it may be too aggressive
plus I like the Tergitol solvent properties.

@terry9 Could you pls link to the diyaudio graph? Thanks

@terry9 Thank you, you shouldn't have spent so much time on that - was just asking out of curiosity. Sorry for causing trouble.

I must say I was perhaps a bit too harsh on US. Most of my experience was based on 10%IPA +0.1% PhotoFlo for 10min at 70% power, 33C, 3rmp, and then a US rinse with DI water to get rid of the crappy PhotoFlo "plastic"sound. Now I’ve cleaned about a dozen of Lp’s using 5%IPA + 0.05% Tergitol, 15min, 70%, 33C, 1rpm, and apart from the record I happened to use for tests (which turned out to be problematic), the rest does show v nicely quiet background with very much reduced amplitude of clicks n pops compared to what I’m used to. I did not take the time to listen inbetween initial vac pre-clean and the US clean, so this subjective opinion is based on the final result of my vac+US+vac cycle (which costs me an arm and a leg - I can’t do more than a dozen Lp’s per day). All in all, at this moment I can say US can be efficient but not out of the box (in the DIY version) - quite some experimentation and tuning needed.

PS I’ve found a 0.5um polyprop filter to better filter the solution....and ordered a Keith Monks record brush to perhaps improve pre-clean too. What I’m failing to find is a small (4-5W) 0.3-0.5rmp motor in EU.

@whart Interesting re the brushes. I've been using brushes (Osage for cleaning, Okki Nokki for the rinse) thinking they create more resistance, which is what I want (I like working harder through the vinyl surface). Never tried pads but will definitely do! I also scrub so motor speed is not an issue - I can create any speed my hands allow ;)  I pre-clean with the same fluid I use for US: 5%IPA + 0.05% Tergitol S7

@whart  Nope, I'm in EU, but can order that, thanks.

@terry9

1) Rotation - I know! See my posts.

2) Rinse - it’s 2 stage :) see above

3) I’m a bit afraid of passing 35C

4) Spacing - I use 6L 150W cleaner with 3records max but at 70% power. The central record is 37mm (the 40Khz wavelength) to both side records. Side records about 30-35mm to the tanks side. Could be more but I can see the ultrasonic action clearly in all the spaces.

On Kirmuss - he seems to go pretty much against all the usual US considerations. Perhaps he is right, I’m not judging. But its seems that in semiconductor industry, where they are most preoccupied with damage, they go not for 80kHz but for 800kHz to eliminate cavitation altogether and rely on acoustical streaming as the main cleaning mechanism. If I’m to buy another tank, I think I’d give 80khz a try, given that I pre-clean with vac anyway so no need for the stronger cavitation power.

BTW, those using Tergitol - what are your rinsing procedures? After  my PhotoFlo disaster I'm quite obsessed with rinsing: I first use high purity water. Distribute it with a rinse brush, rotate 3x with the brush on in one direction then 3x in the other, then vacuum. As the last step, I use 3% ethanol with the same 3x + 3x rotation. Perhaps so many revolutions (6 altogether per liquid) are a waste of time?

@gbanderhoos @terry9

Guys, I don't think that was really necessary. The multitude of approaches and opinions is what makes the progress possible. Quite surprisingly, US cleaning is still a pretty fresh subject even for scientists - I've googled out scientific publications in high impact physical journals as young as 9-10 years (!). Let alone the US use for vinyl, where in the absence of any structured research from the industry, we are left on our own with all the experimentation. So the exchange of ideas/procedures/results is absolutely crucial, no matter if we agree with them or not.

 

@fleschler Have you tried vac re-cleaning/rinsing those Lp's with rolled off highs?

I just changed the filter from 1um to 0.5um. After some 20 Lp's first pre-cleaned with vac the old filter did have some particles left on it - like a very fine grayish sand plus a bit of yellow coloration. So the US does extract something vac did not extract.