I recently became aware of HumminGuru, a Hong Kong based company with a quite forward-looking perspective on the viability of vinyl. While reviewing their affordable and very effective ultrasonic record cleaning machines (HERE), I also discovered a couple of accessories that break new ground for LP spinners.
As with their record cleaners, HumminGuru's only outlet in the US is Amazon (HERE); prices there reflect prompt free Prime domestic shipping, return/replacement privileges, etc–and there are frequent "sales." Products can also be purchased direct (HERE) from Hong Kong, at lower prices, but the customer pays shipping costs, etc. I realize some folks refuse to use Amazon, and we have readers outside the US, so I will list both options.
The HumminGuru I-Brush
The HumminGuru I-Brush Vinyl Record Cleaning Kit is currently under $20 with applied coupon on Amazon (HERE) or $16 on their website (HERE). Yes, another manual record cleaning brush, but different. I have a small drawer full of record cleaning brushes, dating back to the original Decca and Discwasher. There have been many thin dry brushes, featuring fine carbon fiber or goat hair bristles, best used to lightly sweep away random surface dust particles prior to play; they are not effective on fingerprints or groove grime. And the dust tends to end up as a line of debris that has to be swept off the rim of the disc, an aggravation when the humidity drops and static electricity increases.
There have also been many wet brushes, mostly variations on the Discwasher, with wide velvet or microfiber pads. The general approach is to dampen the pad and "clean" the disc, then rotate the wrist a bit to remove any residue with the trailing edge. Too much fluid or pressure and the brush may only push debris further into the grooves. Or, after a few applications, the entire pad can become saturated, and debris picked up can transfer to subsequent discs. Some recent brushes combine the wet pad with carbon fiber dry bristles.
The HumminGuru I-Brush is a rethinking of the wet brush approach. First, by separating the fluid application from the debris removal by using two separate pads to minimize cross contamination. Second, the amount of fluid applied is cleverly controlled. The brush comes with a cradle with a narrow central groove. A supplied eye dropper is used to fill the groove with a precise amount of their alcohol-free, anti-static cleaner.
Pressing the orange pad over the groove in the cradle transfers just a thin line of fluid to the pad, The disc is now cleaned with the orange pad, followed by a sweep with the blue pad to remove any residue. The cradle even has a "wiper" ridge to squeegee off any accumulated gunk from the pads, and the entire brush can be washed and air-dried on the cradle.
In practice, the system was quite effective removing surface debris and reducing static before play, minimizing the problems associated with both traditional dry and wet brushes. Why then even buy a HumminGuru ultrasonic record cleaning machine? Because deep ultrasonic cleaning a truly dirty disc just gums up the filters, and using the I-Brush pre-wash is recommended. Of course, either device can be used independently, but they do complement each other nicely. Besides, any crud in the grooves can and will get scraped up by the stylus.
The HumminGuru S-DUO Pro
The second product of interest is actually a twofer, ($169.99 Amazon or $139 on their website HERE) combining two important stylus care mechanisms, back-to-back on one chassis. One end is a 3 digit VTF (Vertical Tracking Force) gauge, used to measure the down-force of the stylus on the LP. At the opposite end is the totally unique ultrasonic stylus cleaner. Both are battery powered, rechargeable via the provided 5v USB C cable from standard power block or computer when placed on the storage base.
A VTF scale is not just a "bonus feature" free with the innovative ultrasonic stylus cleaner. It's a necessary tool for cartridge set-up. The S-DUO Pro scale includes a 5g reference weight for calibration, after which you merely tap the measure button to zero (00.00) it out. It's very sensitive, so to measure VTF, you should always set the stylus exactly on the little black dot. The display will time out automatically, but you have to zero it out between readings. In practice, you should measure the VTF with the S-DUO Pro sitting on the platter mat, not the LP itself, for geometric reasons as well as disc safety.
This is because the S-DUO Pro's measuring platform sits about 6mm (~1/4") above whatever surface it sits on. In a perfect world, a VTF scale platform would be at the same height as the LP's surface. An average LP is about 2mm thick at the rim, so the recessed grooves sit about 1.5 mm above the platter/mat (a bit higher with thick audiophile pressings). That means the scale platform will still be about 4.5mm higher than a LP when the scale is sitting on the platter mat. But if you tried to measure the VTF directly, that 4.5mm difference tilts the arm up significantly, which changes the VTA (Vertical Tracking Angle) of the arm. Which in turn can affect the VTF, and the reading may be inaccurate. How inaccurate depends on the arm geometry and cartridge design. VTF, VTA, WTF? You are surprised that vinyl spinning involves circular reasoning?
Almost all cartridges come with a "range" of recommended VTF measurements (my Lyra Kleos is 1.7g-1.8g, 1.72 preferred; my Miyajima Zero Mono is 2g - 4.5g). This is partly because the manufacturer can't know how or even if the user measures VTF, so they play it safe. You can probably confirm the range for your cartridge HERE. I'd recommend starting with a value midway up the range. For example, if the range is 2g-4g, use 3g.
Additional tools
In addition to the S-DUO Pro, you may need the appropriate tool (usually a metric Allen wrench) to loosen and tighten the arm height adjustment (assuming your tonearm allows this; some, like the Regas, don't—but see below). The default VTA position for 99% of cartridges is to have the head-shell parallel to the record when the stylus is in the LP grooves. The tool for checking this could be as simple as a lined 3x5 index card placed behind the head shell and, sighting across it, carefully adjusting the arm height at the pivot until the head shell is parallel to the lines on the card. There are also many inexpensive clear acrylic blocks with printed lines available online (google "Azimuth Scales"). They work much better than a card for leveling the head shell, especially if you back them with a contrasting color. Any white or masking tape is fine, but I like yellow USE CAUTION! electrician's tape on the un-printed side. That puts the lines closer to the cartridge, but reverses the printing.
Fortunately, for an adjustable height arm, there is a simple VTF/VTA inaccuracy workaround I've routinely used for various VTF gauges over the years, called indirect measuring. As the HumminGuru scale platform sits 6mm above the platter mat, you first want to raise the arm level with the scale platform. Doing that precisely is easy—CDs are exactly 1.2mm thick, so a stack of 5 is... also 6mm. Set the stylus down atop the the stack, level the head-shell by raising/lowering the arm, and lock it in place.
Replace the CDs with the S-DUO Pro and set the desired VTF with the counterweight.
Put a LP on the platter, then lower the arm without changing the counterweight, and just re-level the head-shell with the stylus in groove by raising/lowering the arm at the pivot. Done.
See, you knew those CDs would come in handy someday.
Rega tonearms and turntables
If you have a non-height adjustable Rega arm on a Rega turntable, it's a bit complicated. You can leave it as is if you use Rega's own or a Rega compatible (HERE) cartridges. Most other cartridges are too tall, so you might not even get the head shell level. OK, you can if you raise the arm mount with a special shim—just Google "Rega shim"; many choices, but 2mm seems to be the most popular.
My old Rega Planar 3 uses a 12.7mm (1/2") thick removable glass platter, with a 1mm platter mat under a 1.5mm high LP surface—so 15.2mm from the sub-platter to where you want the measuring platform to be. I replace the glass platter with an elegant $5 cork/plastic, 10" planter base (mine is 5mm thick) with a 3/4" hole drilled out to go over the spindle. A random piece of 1/4" (6.325mm) plywood would also work.
With the 5mm cork planter base I add three CDs (3.6mm) under the S-DUO Pro (with its 6mm high scale platform) for a total of 14.6mm. For 1/4" plywood put two CDs (2.4mm) under the S-Duo-Pro (14.725mm total). Either is close enough, so measure away.
Optimized Cartridge Setup
Basic cartridge set-up with the S-DUO Pro is easy, but due to factors like manufacturing tolerances assembling the tiny parts of a cartridge, a given sample may well sound better with a bit more or less VTF, and/or a bit of VTA tilt up or down. But take a break and play a few LPs with the head-shell level and mid-point VTF settings the S-DUO Pro provided—just to enjoy your vinyl and familiarize yourself with the sound.
Optimized, a specific cartridge set-up is a more complex process, using your ears to be the judge, and beyond the scope of this review or the S-DUO Pro instruction booklet. Fortunately, there are countless such discussions at online audiophile forums (Google adjusting VTF or VTA). I'll just add a couple tips here.
First, as you will be repeatedly changing settings and listening to one LP, (preferably one that has complex, dynamic music at the end or a side), always take a picture and record the info and results. Second, adjusting VTF precisely by unlocking/moving/locking the counterweight can be frustrating. You may have noticed the odd colored bands on my tone arms. They are large size Clover Coils (HERE), which I got at a local yarn shop. Put one on your tonearm at the pivot end. Set your starting VTF with the S-DUO Pro a bit below your desired setting (i.e., 2.2g rather than 2.5g), and slide a coil a half inch or so at a time towards the head shell, remeasuring to get it exact. Add a second coil if needed to reach the desired value, or to avoid the tonearm rest.
Adjusting the VTA requires an accurate tool to measure the height of the tone arm at or near the pivot (unless your arm incorporates a height scale. Few do). There's no universal measuring tool as every arm and turntable design is different—you typically measure from the plinth or arm board to some convenient point on the pivot housing. You might use a small ruler, with dividers or a compass, anything that works with +/- 1mm (or 1/32") divisions. I've used them all, the most precise on my rig being a digital caliper, used upside down:
But as adjusting tonearm height always seems to require three hands, I've settled on a 6" pocket rule jammed into a gob of temporary adhesive atop a quarter. As the cartridges on the interchangeable wands for my Audio Origami unipivot tonearm require different VTAs and VTFs, I have two with the correct heights secured with different color tape, and marked with the needed VTF. I can change out the the arms in a minute or two.
Ultrasonic Stylus Cleaning
Now's the time, turn the S-DUO Pro around and meet the world's first true ultrasonic stylus cleaner. Yes, there have been other devices that would claim that honor, like my venerable Audio-Technica AT-637, but they have been basically just brushes that are rapidly micro-vibrated, at maybe 3kHz or so, not enough to even wake up your dog.
Ultrasonic record cleaning machines like HumminGuru's may be state of the art for LPs, but lots of delicate and pricey medical/dental, optical, and industrial stuff has long been routinely and safely cleaned in ultrasonic tanks. And of course, jewelers also use ultrasonics: bring in Milady's priceless necklace for an ultrasonic spa-bath, and all the sparkle comes back. Maybe somebody looked at a grubby stylus at the end of a cantilever and realized it's just another dirty diamond.
If you routinely play older records, you don't really want to know where the stylus has been—folks smoked, spilled, sweat and sneezed on LPs over the years, and those fingerprints are greasy by definition. Even new records can suffer from "mold-release compounds" from the pressing process which the stylus is expected to "burn-off." A stylus tracking at 2-grams actually generates a lot of heat and pressure at the minuscule moving point of contact, and all sorts of stuff can end up stuck to the stylus.
If you compare the various stylus shapes available, from the mono-era conical to elliptical to up-market line-contact, Shibata and MicroRidge designs (HERE), you realize the higher costs come from precisely narrowing the edges of the diamond to better track the finest stereo groove modulations. Unfortunately, they also end up looking like miniature garden spades, making them even more efficient at scraping crap off the groove walls.
Naturally, I also have a drawer of stylus cleaning products, including an Audio-Technica AT-637 faux ultrasonic gizmo. There are dozens of options out there: brushes soft and stiff, fluids with surfactant, alcohol, lubricant, or unknown active ingredients, and others that are basically sticky-gel grime-grabbers. They have all worked well enough to remove the obvious fuzz-ball, at least. I was never in with the Linn crowd's idea of using the abrasive strip from a matchbook cover to clean a stylus, or the early internet influencer's suggestion of letting a vacuum cleaner hose suck on the head-shell.
But seriously, the potential of ultrasonic stylus cleaning is simply a game changer. Of course, the basic rule remains… first do no harm. Do check your cartridge manufacturer's cleaning recommendations, keeping in mind they will not discuss ultrasonic cleaning (yet). There are two basic concerns: first, how the diamond is "bonded" to the cantilever, perhaps with a chemically soluble adhesive; the second caution is any tendency of excess fluid to "wick" up the cantilever into the works—particularly if the cantilever is hollow.
HumminGuru is confident their approach is safe. The S-DUO Pro uses only a few drops of distilled water, and when used properly, the stylus is barely dipped in the fluid for a 20 second blitz of 110KHz ultrasonic energy (which can then be repeated if necessary). Of course, as with other intriguing new activities like sky diving, Crypto, or the Kama-Sutra, one wants to follow the directions and exercise caution. The S-DUO Pro manual is well illustrated, so I will focus on my own experience and observations here.
The S-DUO Pro is designed to avoid disaster, but that's ultimately up to the user. Included are three rubber rings with different diameter openings, which can be stored in the unit's charging base along with a couple of drying pads and a mini eyedropper. The ring's rim is where the cartridge body (not the cantilever) will rest, and the distance from that point to the stylus tip determines which size opening is best for a given cartridge.
HumminGuru has a Cartridge Compatibility List (HERE) with recommended rings on their site, regularly updated from user comments, but it's just a small fraction of the thousands of cartridge designs sold over the years. There is no one size fits all, as some cartridge bottoms are square, many angled, a few round, and the most problematic being "naked" ones like my Lyra Kleos. The only similar cartridge on the list when I checked was the $900 Sumiko Songbird. No mention of any of the up-to-$15K, top-of-the-line bare-bottom babies from Dynavector, Van den Hul, Benz Micro, or Lyra, none of which have a housing to rest on a ring.
Lyra is quite specific about minimizing fluid-based cleaning of their cartridges, and as their cantilever suspension is unique, I have held off using the S-DUO Pro with the Kleos, pending a response to my inquiry. There are variants of my (Zu) Denon DL-103 and Miyajima Zero Mono cartridges on the list, so I was more confident dunking them.
I do have some general suggestions. First would be to prevent the turntable platter from rotating unexpectedly by using shims or tape. Second, the ring fitted to the ultrasonic well sits about 9.5mm above the platter mat; the drying pad is about about 12mm high. Not all arm lift levers can raise a cartridge that high, so you might have to use the manual finger lift. Even then, the stylus end will be tilted up, away from the fluid reservoir. In most cases, you can simply raise the pivot end of the arm high enough that the cartridge is level when sitting on the ring as the instructions depict. Third, before cleaning a stylus the first time, do a "dry" run with the S-DUO Pro, lowering the cartridge onto the ring to confirm that when it sits with the cartridge level, only the stylus and part of thecantilever would enter the water—but without touching the bottom or sides of the shallow well. If necessary, adjust the set-up. For some atypical cartridges, see further comments below. My final suggestion is to practice with an older or less expensive cartridge if you have one. First try for me was the inexpensive yet surprising Audio-Technica AT-VM95 I use on the old Dual 5000 in my work-space system–with no problems at all.
Okay, now for the cool stuff. The supplied mini-eyedropper facilitates precisely filling the small ultrasonic reservoir with distilled water, a drop at a time. Place a couple drops in the reservoir, and notice that, just like raindrops, a small puddle of water creates a dome because of water's normal surface tension—the manual's illustration is a bit misleading here, but part of the rubber ring's function is to help level the surface. While the manual suggests filling the well virtually to the top of the ring, I prefer adding water drop by drop until the stylus is barely immersed. You may need a loupe and/or a penlight to facilitate this; I used the $4 green keychain mini-light visible below with the Miyajima Mono cartridge:
Slowly lower the cartridge onto the rubber ring. Add water drop by drop until the stylus is barely immersed, and we're ready to go—you may need that magnifying glass here. Press the "drop" icon button and the unit will start, count down 20 seconds, and shut off.
After 5+ seconds, the cleaning can be repeated, or just lift the cartridge clear of the well, and remove the rubber ring.
Moisten one of the grey drying pads, and squeeze out any excess water. Position the pad in the well to absorb the water; the stylus and/or the cartridge body can also be placed on the pad to absorb any random fluid safely. Residual water in the well can be removed with the eyedropper or cotton-tipped swab.
Unfortunately, while my Miyajima Zero was happy sitting level on the S-DUO Pro ring, my Zu/DL-103 is basically naked under the hood. Part of the "works" protrude below the sides of the enclosure, and might get an unwanted soaking with the cartridge sitting level. It would clearly be "safer" to position the cartridge a bit nose down. The easiest way to do this is to leave the cartridge lift lever all the way down, then raise the arm from the pivot end, position the cartridge over the ring, and carefully lower the arm from the pivot end until the "works" are just above the ring but the stylus is below it, and lock it in place. It will probably take a few tries, and it is difficult to see (or photograph). One way to assure clearance is to rest a small strip of very thin, stiff plastic (clear produce packaging works fine-mine came from a box of blueberries) on the rim and adjust/lower the arm from the pivot end until the "works" lightly sit on it, then remove the plastic. Now you can fill the reservoir drop by drop, raising and lowering the arm with the lift layer after each drop until the stylus breaks the surface with a tiny ripple, and you are ready to go.
The picture below is the dirty Zu/Denon stylus—note the accumulated grunge on the right(rear) side of the stylus, and many years of micro-dust on the cantilever.
Here is the result from carefully titrating the water level drop by drop. Note that only the bottom side of the cantilever and the stylus were cleaned.
To me, that represents precise control of the process. The same approach would work on many "naked" cartridges, too. I have a lifetime supply of "retired" cartridges going back to the Supex and Fidelity Research days to experiment with, and several have bulges below the body, so would also dunk safer nose down, so always check the side view.
Although I normally only play clean(ed) LPs with a "clean" stylus, I had spun up a few iffy LPs straight from the local thrift shop–just to get my styli good and grungy before using the S-DUO Pro. I then also cleaned the LPs with the HumminGuru record cleaning machine, and listening to them again with a clean stylus left me quite impressed. The scruffy LPs turned out to actually be pretty decent, and both of my carts sounded "refreshed and right." No mis-tracking, highs clean and sibilance free, midrange expressive, and bass deep and dynamic. Indeed, a pristine stylus on each cartridge was easily confirmed by visual examination with a 45x loupe or my USB microscope.
You may wish to repeat the S-DUO Pro process for the initial cleaning of a well used cartridge (I definitely want to do that with my vintage stash). Subsequent ultrasonic cleanings may only occasionally be needed if you play clean LPs, and the process will get less fraught as you settle in with this unique new technology. If old school stylus care is like daily use of a toothbrush, the S-Duo is like professional plaque removal at the dentist, but with less floss shaming.
The HumminGuru I-Brush and S-DUO Pro together bring effective, affordable, and cutting-edge tech to the all-important stylus-groove interface—exactly where the magic begins to happen. Add one of their ultrasonic record cleaning machines and you have the complete package for modern analog HiFi hygiene.
Highly recommended!
HumminGuru I-Brush
Retail $25-16
HumminGuru S-DUO Pro
Retail $170-139
HumminGuru
