“One of Hi-Fi’s best kept secrets.” That was how I myself described the Audio-Technica AT150MLX cartridge in its 2015 review, praising its ability to track even the toughest vinyl, and its sound that “can rival a very very good digital front end”. When I wrote that review, I was unaware that less than a year later it would be pulled from the market. Its replacement comes in the form of Audio-Technica’s new flagship moving magnet cartridge, the AT150SA. A cartridge that has split opinion, thanks to the replacement of the microline stylus that made the previous model so desirable with a theoretically inferior Shibata diamond.
Originally invented by Norio Shibata of JVC, the Shibata stylus was designed to track the high frequency (40kHz+) content of the CD-4 quadraphonic records without causing undue groove wear. Like all line contact styli, the Shibata stylus maximises contact with the groove walls which in turn means less surface pressure and thus less groove wear. The more technologically advanced MicroLine or MicroRidge styli are laser cut and comprise a pronounced ridge at their tip. This lessens inner groove distortion and increases the life of the stylus tip, as the curvature radius of the scanning surface of the tip is worn such that it remains consistent, extending the life of the tip and also reducing groove wear.
I myself was sceptical. Viewing the cartridge as an exercise in cost-cutting at the expense of the consumer, and wishing I’d done so before the inevitable price hike that occurs when stock levels of any desirable product are nearing depletion, I quickly purchased one of the last remaining AT150MLX models available in the UK. Typically however that cartridge had a manufacturing defect (it happens to the best of them), and by the time the cartridge had been through the check / refund process the MLX cartridge had all but disappeared from the UK market, leaving only used examples and Japanese imports, none of which I was particularly interested in chancing.
Needing a cartridge for a newly purchased Technics 1210, I decided to purchase a new AT150SA to see how the 2 models compare and whether my scepticism was warranted. On the surface at least, the 2 cartridges are fairly similar, sharing the same body style and dual magnet paratoroidal signal generator. Even the stylus assembly looks identical, complete with the flip-down stylus cover that received my approval on the previous model. However where the at150MLX featured a microline stylus mounted to a gold-plated boron cantilever, the AT150SA sports a Shibata profile diamond mounted to a tapered aluminium cantilever.
Even the packaging has been carried over from the previous model. The cartridge is housed in a plastic display case, mounted to a device that also serves as an overhang gauge. In a separate compartment, a bag of accessories includes a small flathead screwdriver, 4 screws of both 5mm and 8mm lengths, 2 nuts, 2 washers and a stylus brush. You also get a set of the same PCOCC headshell wires as supplied with the previous model, along with some documentation.
Specs wise, the frequency response is rated at 20-25000Hz. Channel separation is rated at 30 dB (1kHz) balanced to within 1dB, and the cartridge outputs 4MV at 1kHz, 5cm/sec. Recommended loading is 47K ohms at 100-200PF capacitance.
As with all products the pricing can vary. Introduced at £299.95, the AT150SA can at the time of this writing be had for as little as £264. The previous MLX could be had for as low as £215 before being discontinued,. I don’t see the 150SA dropping below £250 any time soon, but with retail competition being what it is who can say. It’s priced competitively, below rivals such as Ortofon’s 2M black which retails for almost twice the price.
The AT150SA was mounted to a standard 7 gram Technics headshell, and then to the stock tonearm of a Technics SL-1210 MK2. The included PCOCC wires were used, and the cartridge aligned to the Technics standard alignment. Unlike other alignments, the Technics is designed to optimise the tracking angle for minimal distortion at the inner grooves of the record, which are the most difficult to track and thus are where the distortion is most prevalent. Other alignments aim to equalise the distortion across the surface of the record. The Technics alignment was chosen simply because it is the alignment for which the arm was designed, and in reality the audible difference between alignments isn’t significant providing the null points (the 2 points on the record where there will be zero tracking error) are correctly chosen.
I opted to ignore the overhang gauge and used a custom alignment protractor, and would suggest you do too. With its Shibata stylus, the AT150SA requires careful setup and fine tuning of all parameters, including alignment, vertical tracking force (VTF) and, to some extent, vertical tracking angle (VTA). Though I don’t believe the latter to be as important as many would have you believe, achieving a rearward arm height that results in the arm being parallel to the record will optimise the vertical position of the stylus within the record groove.
As for the vertical tracking force, Audio-Technica recommend a range between 1-1.8 grams, with 1.4 being the standard value. The AT150MLX, for which no standard tracking force was specified, tracked best at 1.6 grams. Here the recommended 1.4 grams was found to provide optimal results. Anti-skate compensation was set to around 1.3 grams, though of course both the tracking force and anti-skate compensation settings will differ slightly depending on the turntable and arm used.
While the AT150MLX was without doubt an incredible cartridge, it wasn’t particularly adept at portraying a large stereo image, nor did it flatter poor recordings or poor pressings. The AT150SA is a cut above its predecessor in both areas. That Shibata diamond gives it a mid range presence that the 150MLX was lacking, resulting in a far more coherent and musical sound with excellent imaging. Sound stages are truly magnificent extending into a seemingly infinite space around the speakers.
It’s less revealing of the deficiencies in poor pressings too, though its ability to track louder pressings capable of sending many cartridges into fits of distortion are equal to that of the 150MLX, if not a little better. It does an admirable job of tracking well worn albums, a truly ruined (though cleaned) copy of Bat Out of Hell was perfectly listenable, the soft crackle of a well loved vinyl only serving to add to the recording where on many cartridges it would render the sound unpleasant. And that little bump in the mid range doesn’t come at the expense of detail. The 150SA unearths a lot of information from the grooves of the record, and presents them in a coherent yet musical fashion that is non fatiguing and a joy to listen too for hours on end.
As it turns out, my scepticism was thoroughly unfounded as the AT150SA is a worthy successor to the long running and highly revered AT150MLX. While it certainly may be true that cutting a Shibata diamond is less costly than cutting the microline tip of the previous model, I don’t personally feel that the AT150SA was a cost-cutting exercise on the part of Audio-Technica. Rather it is a cartridge that builds upon the strengths of the AT150MLX, taming its sound that is, in comparison, somewhat cold and clinical.
If you’ve been holding out, waiting to see whether the 150SA attains the awards and commendations of its predecessor, look no further. If you’re desperately searching the market in an attempt to uncover an AT150MLX, I’d suggest you simply opt for the AT150SA instead. The AT150SA may just be one of, if not the best moving magnet cartridges on the market. Highly recommended.