Tima’s DIY RCM

Tima’s DIY RCM

As a dedicated vinylista, I’ve been cleaning records for over thirty years. Sound familiar? Cleaning techniques and technologies evolved across that time and my approach changed with the times. I’ve been using a Loricraft RC3 point nozzle machine and more recently an Audio Desk System. After reading multiple threads on various audio forums about home made record cleaning kits built around larger volume ultrasonic cleaners, I decided to give that a try. Thanks to all who have gone before me, and especially to Bill at The Vinyl Press and Rob at Audionirvana.org, for encouragement, and to those who pointed me at the diyAudio site and an article in the Positive Feedback e-zine from Rushton Paul.

First, I purchased a Kuzma RD – As with everything Franc Kuzma makes/invents, his RD (rotating and drying) device is rational, easy to use, and top quality. It’s a motorized rotisserie type device that slowly spins records immersed in an ultra sonic cleaner (USC) machine. Kuzma claims that with the right USC tank it can clean up to 10 records at a time. You supply your own USC. Franc quotes the RD msrp at 1,200 EUR.

Franc Kuzma provides a list of USC machines that meet the dimensional requirements of both the RD and those features he believes a USC should support. He uses and recommends the Elmasonic P 120H 13 Liters (roughly 3.5 gallons) – a really high quality German made USC that includes power control and the ability to operate at two different frequencies: 37kHz (larger cavitation bubbles, stronger implosion) and 80kHz (more gentle action but smaller bubbles assured of getting deep into the groove). He suggests you select an USC with standard features that include a timer and temperature adjustable heating. Being the only unit I found to support multiple frequencies I really wanted to try the Elmasonic unit, but without any experience in this area I was a touch hesitant at it’s ~$2400 USD price.

I opted for a Chinese unit from Beijing Ultrasonic that had all the major features except the multiple frequency operation (only 40 kHz). Dealing directly with the factory was easy – they shipped their 10 Liter (~2.5 gal) model direct for a total of $350. I figured I could buy 6 of those for the cost of the Elmasonic and wanted to try out the concept before shelling out more dinero for the nicer brand. I may convince myself about the Elma, but not this year. 🙂

Inspired by user bbftx’s write-up on the diyAudio forum led me to add a filter to the process in order to continually cleanse the USC water as it bathes records. Not being particularly DIY myself, I adopted his design and managed to build a one micron (0.001 millimeter) filter driven with a pump. Doing that just took a little thought along with finding the appropriate parts and assembling them. I made a few small variations but he gets the credit. See his write-up here.

Here are the pieces of the Kuzma RD laid out for assembly. Audio cat Finzi checks it out as the Audio Desk RCM looks on in horror.

​​Putting together the Kuzma RD was super simple – it took twenty minutes.
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Here is the Kuzma RD with motor unit attached. It is height adjustable for use with different USCs while the Kuzma RD Web page gives length and width parameters with a list of suggested USCs.

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Here are the innards of the pump and filter. This option cost me ~$120 to build. I sourced every part separately with the biggest cost item being the pump motor. I’m using a 3/8″ intake from the USC and 1/4″ output to the filter and back to the USC.

 

 

Amazingly everything worked at the first test! My theory about the filter and diluted cleaning formula (below) is that I don’t need to worry about a separate rinse step. I’m sure there will be some who disagree with that concept though thus far I feel confident in this approach. Thus far I haven’t found a filter at less than 1 micron that fits in my canister – still that’s fairly fine. I believe an RO membrane would not allow sufficient throughput. I’ll see how it goes with more experience.

 

∞ 

Being audiophiles requires wrangling about stuff and there is plenty of debate about cleaning solution formulae. You may want to read LondonJazzCollector’s article on cleaning fluids.  

For now I am using roughly 2.5 gallons of distilled water with 200ml of Isopropyl Alcohol and 5ml of Ilford Ilfotol, a wetting agent.  It is not uncommon to read suggestions of 200ml IPA and 5ml wetting agent for each single liter of water so what I’m using is a highly diluted formula.  I’ll try different proportions down the road. But I’ll tell you the results I get with this less-is-plenty formula are spectacular. Temperature is another topic of discussion. For now I’m heating the water to 32° C (~90° F); the USC thermostat control makes this easy.

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You see records on their spindles ready for cleaning. Supplied pucks separate the records and the spindle mounts on the RD frame. At the lower end of each spindle is the gear that meshes with a gear on the motor that drives spindle rotation. Once finished in the bath, the spindle and records fit back on their support for drying. I bought an extra spindle to increase throughput. The Kuzma RD holds up to 10 records, but there is discussion about allowing enough space between each record for cavitation effectiveness. With my 10L 240W machine I cleaned no more than 6 records at a time at roughly 1.5 inches between records. There is a correlation between the power (wattage) of the USC, the bath size, the number of records for cleaning and the space between them.

For me, one of several objectives to this approach is throughput with maximal cleaning. When I’m in a record cleaning mood, I can process ~32 records in a couple hours including drying and bagging them up. Using a single slot RCM would take much more time than that, much of it in constant attendance to the machine, record after record. I found using the multi-record USC method no less methodical but more relaxing because I can leave the room, do other tasks like preparing inner and outer sleeves for new records and don’t hear the noise. With my USC, RD motor and filter pump all going a once, the noise, while still ‘buzzy’ is definitely less than an Audio Desk or KLAudio unit.​​       

Above is the setup in production. Before starting off on a cleaning run you can degas the cleaning solution by letting the USC run on its own; I degassed the water for 15 minutes.

With degassing started, I turn on the bath heater and pump+filter which I let run throughout the cleaning cycle.   After degassing completes, I load a spindle with records mounted.  At 9V the RD motor rotates the swatch of records at ~.5 rpm.  Typically I’ll set the USC timer to operate for 15 minutes and set its power level at ~60%.  Sometimes I’ll clean the records for an additional 5-8 minutes with the USC power level set at ~75%. 

 Here are cleaned records air drying. The spots you see are water droplets. I was skeptical of air drying but it works fine, just takes a while. I will also use a small (4 inch) fan at a 3 foot distance to keep air circulating in the drying area – this helps speed up dry time.

When I solely used a Loricraft point nozzle RCM I was a huge believer in plenty of clean water rinsing. For now with a highly diluted cleaning solution and active filtration I have no rinse step. I put drops of cleaning fluid on various surfaces, including white paper and white and clear plastic to see if there was residue when it dried; under magnification, I observed no residue.  

Once everything is ready to go, it is easy to clean multiple records with this setup. In terms of results, I’m very satisfied and a bit surprised. As the ancients teach us, you can never clean the same record twice, so gauging results between different methods can be dicey. Nonetheless, across new records, uncleaned records, older records in various states of prior cleaning (multi-step hand cleanings and rinsings with AIVS fluids and my Loricraft PRC-3, Audio Desk cleanings, etc.) this DIY setup offers top-notch sonic results. For now, I’m sold on this USC with filter. It yields better results than a single slot RCM, is less expensive than a standalone automated machine, and costs less money. While using a Monks or Loricraft point nozzle machine with plenty of fluid and light fluid agitation remains quite effective (albeit tedious), I have only so much real estate to devote to record cleaning. Today, the multi-record USC gets first claim on that space.

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Tima is Tim Aucremann. After years living in the 18^th and 19^th Century with Hume, Kant and Hegel, Tim switched to a career in IT architecture and project management. An avid audiophile since trading in his Bose 901s for Maggies and a Hafler DH500 kit, today Tim continues “Living La Vida Vinyl.” He writes for Positive Feedback.