02/05/2023
HOW TO BUY A PHONO CARTRIDGE
The cartridge is the heart of any vinyl rig. This is where the physical grooves in the records are converted into electrical music signals. The phono cartridge is a simple yet complex tiny electromechanical marvel. The principle is simple, but implementing it perfectly is ever so complicated.
PRICE
Phono cartridges can be bought for a few dollars, or for a few thousand dollars. As with anything, there’s a point of diminishing returns, which is different for all of us, but at a certain point, the perceived difference is no longer worth the cost.
However: The cartridge is THE single part of a turntable rig (above a certain minimum quality at least) that can make the biggest difference in sound. The tiny parts of fine mechanics aren’t easy to make, and most cartridges are (to a degree) hand built.. Tolerances cost money, and at this tiny scale, narrowing the tolerances to make a more precise cartridge raises the cost exponentially.
We won’t put a number on it, but as the cartridge is a very important part of a vinyl playing system, it should be allocated a considerable part of the budget. Many turntables are sold with a cartridge not matching its quality, and I’m often tempted to see them simply as “placeholders”.
TYPES
There are a few types of phono cartridges available. We’ll just leave the ones for 78/shellac and mono records alone for now, concentrating on the most common variants, for playing stereo LPs. (Yes, yes. Of course a stereo cart can play mono records.)
MOUNTS
P-MOUNT/T4P
P-mount cartridges are a great idea for maximum user friendliness. Their mass, compliance and geometry are standardised, so all you have to do is to plug one into the end of a tonearm with this mount, secure it with one little bolt, and you’re all set. No need to worry about mass/resonance matching, geometry, protractors, null points or overhang like you need to with a standard mount.
The drawback is that the selection of cartridges with T4P mounts is very limited, and they are mostly found in the lower end of the quality spectrum.
There are adapters available for using T4P cartridges in a ½” headshell, should you want to.
HALF INCH/STANDARD MOUNT
The ½” mount is the most common, and what the majority of cartridges are built for. The cartridge is attached to the headshell of the tonearm with two M2.5 (or sometimes, annoyingly M2.6) bolts ½ inch (12,7mm) apart. The tonearm wires have to be connected to the cartridge manually. (Carefully!) Sometimes, the headshell is detachable from the tonearm, making assembling a cartridge a lot easier.
There are also a few cartridges that mount to the tonearm as one combined headshell/cartridge unit. These are also plug and play. Many DJ carts are like this, as well as Ortofon’s classic SPU series, etc. These fit tonearms with detachable headshells and SME type headshell mounts only. A few cartridges are sold pre-mounted on headshells that also fit such arms.
MC, MM OR MI
The way phono cartridges work, (Again, let’s leave old, ceramic carts out of it for now.) is by electromagnetic induction. (Remember Faraday’s Law from High School?) When a coil of conducting wire is moved within a magnetic field, an electrical current is induced in the coil. The three main principles for implementing this in a phono cartridge are as follows:
MOVING MAGNET (MM)
Most cartridges sold today are MM. They are the easiest to build and therefore the cheapest. The magnet is attached to the end of the cantilever and moves around when the stylus follows the record grooves. The conductor coils are fixed in place in the cartridge housing.
MM carts have reasonably high output levels and don't need as much amplification in the phono stage as MC carts do. This makes MM phono stages simpler and cheaper too, and these are ordinarily the ones built into amplifiers and turntables.
Another big advantage with MM carts is that the design makes it possible to make them with user replaceable styli. MC carts don't have that.
MOVING COIL (MC)
In Moving Coil carts, the inductor coils are attached to the cantilever and the magnets are fixed in the cartridge housing. Because the coils are considerably lighter than the magnets, MC carts have a much lower moving mass than MM carts. This gives them better tracking ability and dynamics. MC carts start a little higher up the price ladder than MM carts, and they climb quite a bit higher up it’s high end too. Those several thousand dollar carts we mentioned, are MC.
MC carts have considerably lower output levels than MM carts, and put greater demands on the phono stage. Both in terms of gain and adjustability.
There are also High Output MC carts. These are wound with bigger coils to boost the output level enough that they can be used with phono stages built for MM carts. Some see it as a great way to get an MC without swapping their phono stage, others see it as “the worst of both worlds”. Regardless of that: One of yours truly’s favourite cartridges, and possibly the most engaging and fun cartridge I have ever tried, was a HOMC.
Although MCs don’t have replaceable styli, they can be retipped or rebuilt by the manufacturer. ...or by a third party. Retipping means cutting and splicing the cantilever, so everybody might not be completely comfortable with everybody’s methods of doing that. A rebuild by the manufacturer should be like getting a brand new cartridge, though. Other manufacturers offer a discount on a replacement cartridge instead.
MOVING IRON (MI)
In a moving iron cartridge, both the magnets and the coils are fixed, and a piece of iron is fastened to the end of the cantilever, moving around in - and changing - the magnetic field. These also have a low moving mass.
For most other practical intents and purposes, they can probably be seen as a subset to MM carts, but be aware that some MI cartridges have as low output voltage as MC carts.
OPTICAL
It’s also worth noting that recently, optical cartridges have popped up. They’ve thrown electromagnetic induction out the window and are using optical sensors to detect the stylus’ movements and to generate the audio signal. They need special phono stages. Neither said carts or phono stages are cheap at this time.
STYLUS PROFOLES
Simply put, there are three main categories of stylus tips:
-Spherical/conical
-Elliptical
-Line contact
In addition to this, styli can be “bonded” or “n**e”. A n**e stylus means the whole stylus is one piece of diamond that is attached to the cantilever. A bonded stylus is a small diamond tip glued to a piece of cheaper material that in turn is attached to the cantilever. The latter adds mass, which decreases tracking ability and in a worst case scenario, also a big glob of glue.
SPHERICAL
A spherical “or conical” stylus is the cheapest and simplest type in use today. This type of stylus is a circular cone with a spherical, “blunt” tip. Because the tip’s relatively large radius and the tiny contact point it has with the groove, the amount of detail it will pick up from the grooves will be reduced compared to more advanced styli, and the higher pressure in the tiny contact point will probably increase record wear.
They are, however, the most forgiving in terms of setup, and very cheap.
ELLIPTICAL
One way to slightly increase the stylus tip’s contact area with the grooves and to narrow its profile, is to flatten the round stylus cone into an oval. That makes it an elliptical stylus. A sharper profile that drops further into the groove, picking up more detail than a conical stylus. The narrower side diameter improves tracking and reduces high frequency distortion. (Sssssibilance, etc.)
LINE CONTACT
Line contact stylus tips are more advanced refinements of the elliptical stylus, where the diamond is ground into clever shapes to make the stylus profile more like the cutting head that made the original grooves, to land even deeper in the grooves and to increase the contact area between the stylus and grooves even more. Manufacturers often have their own names for their own line contact stylus profiles, like “Shibata”, “Gyger”, “Van Den Hul” and “Microline”
The more advanced the stylus profile is, the deeper into the groove it rides and the bigger its contact patch is, the more detail it can pick up and the better its tracking ability gets. But there’s no such thing as a free lunch! These advanced shapes are expensive to make, and they demand a great deal of precision in aligning them. Set up correctly, a line contact stylus will dig the absolute most detail and quality out of your records, and laugh at stuff like Inner Groove Distortion. The most advanced stylus tips also cause the least amount of record and stylus wear. BUT: If they are poorly aligned, the wear caused by the sharp stylus can actually be worse.
CANTILEVER MATERIAL
The cantilever (The “rod” that sticks out from the front of your cartridge, with the stylus tip in one end and magnets or coils in the other.) should be as light and stiff as possible.Up to a certain level, they generally are aluminium tubes, but more advanced designs use materials like boron, carbon fibre, diamond or even cactus spikes. (OK. I admit it. Cactus cantilevers are rare.)
COMPATIBILITY
This is the part I suppose many will skip, but it’s still very important. A phono cartridge needs to be matched to the tonearm it is mounted on and to the phono stage it’s connected to. Here’s what you should consider:
If you don’t want to deal with all this, just make sure you get a cartridge with similar mass and compliance specs to the one you have.
TONEARM
The tonearm, including headshell and cartridge, is a mechanical system consisting of a weight suspended by a spring (the cantilever suspension). That system has a resonance frequency which we need to manipulate. The system’s natural frequency should be above the typical frequency of record warps (4-6 Hz) and lower than the audible spectrum and/or your system’s frequency response. The normal goal to aim for is the 8 to 11 Hz range.
To do that, we need to know:
-The tonearm’s (including headshell) effective mass, (Not its actual mass, but “the mass it seems to have when responding to forces”. This will be in the tonearm manufacturer’s specs. You can do the math, or reverse engineer it using a test record and a cart with a known compliance, if you really want to.)
-The cartridge’s mass.
The cartridge’s dynamic compliance (Measured in um/mN at 10Hz. (Or 10-6 cm/dyne which is the same unit if you do the math.) Some manufacturers, like Audio Technica and other Japanese suppliers, specify the compliance at 100Hz. If that’s the case, we can multiply by 1.7 to 2 to approximate the 10Hz compliance. If you get a “static compliance” number, divide by two to approximate the dynamic compliance at 10Hz. These won’t be exact, but in the ballpark will suffice.)
You can do the math for this too, but anyone not masochistic will just use the calculator at Vinylengine: Vinyl Engine's Cartridge Resonance Evaluator
Punch in your tonearm’s effective mass, find your cartridge mass along the top (adding 0.5 grams for mounting bolts) and your cart’s compliance along the left side. Where they cross is your resonance frequency. If it’s in the green, you’re OK. (In a pinch, it is possible to add weight to the head shell using special spacers or bolts to increase the effective mass.)
To make a long story short: Heavier arms need stiffer cartridges (low compliance) and lighter arms need softer cartridges (high compliance.)
..Oh, it’s also worth noting that if your new cart is taller or lower than your old one, make sure there is a way to adjust the VTA on your tonearm if necessary. (Worst case: It can always be done with spacers and mats.)
PHONO STAGE
For MM carts, this is pretty easy. The industry has standardized all MM carts to work with a load impedance at 47KΩ, and that is what every “MM” input is fixed to. They generally need about 40-45dB of gain on their typically around 5mV output to end up at a sensible level out of the phono stage. Some MM phono stages have the option to load the cartridge with extra capacitance to tame the top end a bit if necessary, but that’s pretty rare. And if necessary, that can be done with a longer interconnect.
For MC carts, it’s a whole other ballgame. Depending on your phono stage, it may be dead easy, or quite a bit of work. It’s not something most people dig too far into anyway. Most modern MC phono stages probably have a simple way of changing these settings, though.
An MC has much lower output than an MM. Around 0.3 mV is pretty normal. Meaning that they’ll need around 60-70dB of phono stage gain.
They’ll also need the correct load impedance. There will probably be a recommended figure in the manufacturer’s specs. (If not, or if you’re just a nerd like me, a starting point for finding the correct load impedance setting on your phono stage is 10-20x the cartridge’s internal coil impedance if you’re using active amplification for boosting the signal to MM level (And if you don’t know otherwise, you probably are.). If you’re using passive step up transformers, your load impedance should be around 1-5x the cartridge’s internal coil impedance.)
These settings should be available on your phono stage to experiment with, if you’re so inclined. Playing with the loading can change the sound pretty noticeably.
MAINTENANCE
There’s not much you can do in terms of maintenance of your cartridge, except being careful not to damage it. The stylus tip, cantilever and suspension are very fragile, so don’t touch them unnecessarily. ..Which for the most part means: “Don’t touch them at all!”. Keep the stylus clean, of course, with a stylus brush, giving it a gentle stroke forwards from the rear, without applying any pressure at all to it. ...Or by lowering it - using the arm lift mechanism on your tonearm - carefully onto a sticky stylus cleaning pad like the “Onzow Zerodust” and lifting it again. Some people clean their stylus quite often, but others, like yours truly - clean it only when necessary. When there’s visible dust and grime on it, or when it just feels like it has been too long, that is. The Zerodust sticky pad seems a gentler and better solution than a brush. Just be careful!
The best way to maintain your cartridge is making sure your records are always clean. (!)
Of course, making sure that your cartridge is properly aligned also minimizes wear on both it and your records.
I also recommend always using the arm lift lever to lower and raise the stylus onto the record, to avoid any expensive mishaps.
LONGEVITY
How long will a cartridge or stylus last? That’s a common question. Manufacturers often recommend changing it after 1000 hours of use, and that number is thrown around a lot on forums etc. as well.
Different stylus profiles wear out at different speeds, and of course it also depends on how clean your records are.
Some enthusiasts buy USB microscopes to inspect the stylus tip, but of course: Then you will have to know how to identify and quantify stylus wear.
Of course you have to listen for sound degradation, and try to recognise stylus wear that way. The problem with that, however, is that such degradation will be very gradual, and might not be easy to notice.
Some will keep track of the hours, some will swap on a time schedule and others will play with the same stylus forever and just don’t care. Just remember that a worn out stylus will also damage records. And, of course, many are also overcome by the urge to upgrade long before stylus wear becomes an issue.
ALIGNMENT
We won’t go through this in detail here. A proper article about cartridge alignment might be written in the near (or distant) future. Just remember that when attaching a new cartridge to your tonearm, it will need to be adjusted and aligned properly. It will need to be mounted to the headshell at just the correct position and angle. Your turntable probably came with a template for this. Additionally, your tracking force, vertical tracking angle and anti-skating will also probably need to be readjusted. Many find that tinkering with this yourself is an interesting part of the hobby, while others happily leave it to their dealer to sort out.
If all you’re doing is replacing the stylus on an existing cartridge, it will be a simple plug and play process.
EXAMPLE CARTRIDGES
Again, not recommendations as such, but noteworthy options from different design principles
AUDIO-TECHNICA AT-VM95 SERIES
This is a perfect example of the advantages of MM cartridges with replaceable styli. If you have a cheap OEM elliptical stylus in an AT-VM95E, you can upgrade to a Microline or Shibata stylus by just swapping the stylus. Plug And Play for relatively little money:
DYNAVECTOR DV-10X5 MK2
Remember I wrote earlier about a High output MC that maybe was the most “fun” and engaging cartridge I have tried. That was this one’s predecessor. The Mk2 have been upgraded from elliptical to Shibata profile:
NAGAOKA MP-200
Nagaoka makes awesome and musical cartridges. The MP-200 is at a sweet spot in the range. An MI with a boron cantilever and a very sharp elliptical stylus.
HANA SL
Excel Sound Corporation has built cartridges for other brands for over 50 years, and when they decide to launch their own brand packed with all their know how at very competitive prices, it’s time to sit up and take notice. This one is a low output MC.
LYRA DELOS
When Japanese masters of their craft put their pride in their work, skill and meticulousness to use, great things happen. This is also a LOMC, or “MC”, as the “low output” usually is implied.
VIABLE UPGRADE PATH EXAMPLES
We’ve run the numbers on a few popular turntables and have come up with possible upgrade paths for them. Just as examples, or as inspiration to look into it on your own turntable.
PRO-JECT DEBUT CARBON
The Debut Carbon has a very light arm, with an effective mass of just 6 grams (Debut Carbon (DC) – Pro-Ject Audio Systems), which means it’s set up with a light, high compliance cartridge. It comes with the well known Ortofon 2M Red as standard. (7.2 grams / 20 µm/mN compliance)
A very simple way of improving its tracking ability would certainly be to replace the 2M Red stylus with a 2M blue. Plug and play. Pull off the old on and slide the Blue on, and you’re done. Bonded elliptical upgraded to n**e elliptical.
But, if we try to make it a little more interesting, how about upgrading to an Audio-Technica VM750SH? Sure. That’s a stretch for a budget table, but it will sound good, and it could always be the first step on a further upgrade path. The cartridge could be moved over to the owner’s next turntable down the line. Anyway, let’s see if it works:
VM750SH - Dual Moving Magnet Cartridge tells us that the VM750 weighs 8.0 grams with a dynamic compliance of 10 x 10-6 cm/dyne (100 Hz). An example of a Japanese manufacturer speccing compliance at 100Hz. We want it at 10Hz, so we need to approximate the number by multiplying the 100Hz dynamic compliance by 1.75 to 2.0. Let’s call that 19 µm/mN.
Punching in 6 grams of tonearm effective mass into the calculator at https://www.vinylengine.com/cartridge_resonance_evaluator.php, and finding where 19 µm/mN and 8.5 grams (for the cartridge and mounting bolts) intersect, we see that the resonance of that combination would be around 10Hz. Well into the green. Perfect!
The VM750S is 0.7mm lower than the 2M Red, which will increase the tonearm’s VTA (Vertical Tracking Angle) by 0.2 degrees. This is completely negligible, but if you want to compensate for it (Personally, I often find that an ever so slightly negative VTA sounds better as well.) you could do so by using a 1mm cartridge spacer shim between the headshell and the cartridge.
Another alternative to the classic Red to Blue swap, would be spending the same as a 2M Blue stylus costs on an Audio-Technica AT-VM95ML or VM95SH. That’s a Microline or Shibata cartridge for less than the price of a 2M Blue elliptical stylus. (!!!) Of course, that means you have to align the cartridge and redo your tonearm settings.
AUDIO-TECHNICA AT-LP120
It’s pretty much impossible to find any specs on the tonearm on the LP120 anywhere. It is possible to do this by using a test record to find the system resonance and estimating it from the cartridge’s known compliance. ...BUT: Since this turntable comes bundled with the Audio-Technica AT-VM95E cartridge, there’s a much easier option. Almost a “no brainer”.
Replace the Elliptical stylus with an original VM95 series Shibata or Microline stylus. AT-VMN95SH or AT-VMN95ML. Plug and play! No research or work involved. Line contact styli at great prices. Job done!
This goes for all turntables that have a lower end AT-VM95 series cartridge, of course.
Note: The AT-VM95 series replaced the AT95 series only a couple of years ago. If you have an LP120 with the older AT95E cartridge, you’ll need to replace the whole cartridge. Which includes aligning it and setting up the tonearm.
REGA PLANAR 1
If there was ever a prime candidate for a stylus upgrade, it’s the Planar 1. The Rega tonearms - even the cheaper ones - are pretty solid and can handle big upgrades, and the included Rega Carbon cartridge, which is a rebranded, bonded spherical stylus Audio-Technica AT3600L is easily improved on.
Rega doesn’t list any mass specs for the RB110 tonearm, but since almost every other Rega arm has an effective mass of 11 grams, it is safe to assume that this one does too.
It is very tempting to just recommend the Audio-Technica AT-VM95ML for this too, which would probably be a stellar upgrade and a good fit, but to mix things up a little, how about an Ortofon 2M Bronze? 7.2 grams, linear contact stylus and 22 µm/mN compliance. Punch in 11 grams in the calculator at Vinyl Engine's Cartridge Resonance Evaluator and find 8 grams (cartridge and bolts) and 22 µm/mN to see where they line up. In the green, at 8Hz. That’s sorted then. :)
Normally, Rega cartridges are much lower than others, and when swapping a Rega cartridge for an ortofon, you’d normally need to compensate for this by adding Rega’s spacers under the arm base to correct the vertical racking angle. In this case, however, the Rega Carbon/AT3600L is 17mm tall, just one mm lower than an Ortofon 2M, so it should be perfect.
TECHNICS SL-1200MK2
Finally, a setup I have been playing with in my head for ages. The classic workhorse from Technics has a 12 gram effective mass tonearm, with the light 6 gram original headshell. If we swap that for a 12 gram Jelco HS-25 headshell (or similar), we’ll raise the effective mass to probably around 16 grams. Now, the Dynavector 10x5 MK2 I have been raving about (A Japanese manufacturer that apparently specifies dynamic compliance at 10Hz) is a little stiff at 12 µm/mN, and weighs in at 7.5 grams. (8 grams with bolts.) Looking at the Vinylengine calculator, we’re smack dab in the middle of the green zone at 10Hz. I’m going to own this as a second setup sometime in the future. Mark my words!
