Audio Technica AT-OC9ML/II

Type: Moving Coil (MC)
Stylus: Nude MicroLine
Compliance: Medium
Price: £400

RECOMMENDED

Background

The Audio Technica AT-OC9ML/II is my only low-output moving coil (MC) cartridge, although I do own a high-output MC. Therefore, this review is written against a backdrop of predominantly moving magnet (MM) cartridges. When I bought my first phono pre-amp with an MC input, I was keen to experience my first low-output MC cartridge and was looking for a good entry-level model. Then I was offered a used, low-hours AT-OC9ML/II on my entry-level budget and I bought it. The cartridge features Audio Technica’s MicroLine stylus, which has an enviable reputation for tracking, mounted on the end of a boron cantilever (another first for me). The cantilever is so fine that it is actually difficult to see in some lights, which makes brushing the stylus a nerve-racking experience. I use this cartridge in an ADC LMG-1 headshell on my Technics SL1200 Mk5, the set-up on which this review is based.

Equipment

Turntable: Technics SL1200 Mk5 with ADC LMG-1 headshell
Phono Pre-amp: Musical Fidelity M1 ViNL (with 47kΩ impedance)
Amplifier: Yamaha A-S501
Speakers: Q Acoustics 3050

Sound Quality

Given its price tag, my expectation was that the AT-OC9ML/II would give me the full MC experience. However, it is difficult for me to discern between the qualities that are down to this specific cartridge and those that are common to MC cartridges in general, so this is a bit of a novice review. 

Treble: The treble is evidently very clean and clear. The MicroLine stylus excavates the grooves for high-frequency detail to great effect, and these frequencies are delivered in a measured and controlled manner with delicacy. Thus, the high-res information is not presented in an analytical or over-powering fashion, but manifests itself by way of texture and refinement.

Midrange: Like the treble, the mid-band is exquisitely clear and detailed. It lends a sense of presence to vocals and texture to midrange instruments. Sibilant vocals are delivered with virtually no fuss at all, thanks to the superb tracking of the MicroLine stylus.

Bass: The bass is pretty taut and textured, and goes down deep. It has a quality feel and, like the treble, is delivered in a measured way, my only reservation being that it sometimes lacks punch.

The cartridge achieves a very well-integrated sound with a neutral overall balance. Quality is undeniably high across the full frequency range. This results in a clean, smooth, sophisticated sound that is extremely easy to listen to – this cartridge is unlikely to induce listening fatigue. Dynamics may suffer a little in this controlled delivery, but the sound is sufficiently lively and expansive to keep me happy. This is a cartridge with a character that tends towards the mellow and is capable of great finesse, which I guess is what you’re paying for.

Tracking

The tracking-force range for this cartridge is 1.25-1.75g, with a normal value of 1.5g, which is the value I adopt. The exceptionally clean sound of this cartridge is surely down to its superb tracking abilities. Notably, the MicroLine stylus works wonders with sibilant pressings.

Compliance

The dynamic compliance of this cartridge is quoted as 9 cu at 100Hz, which translates to about 16 cu at the more usual 10Hz. This makes it a medium-compliance cartridge, most suited to medium-mass tonearms. The Technics arm with ADC headshell on which I use the cartridge has an effective mass of around 12g, at the bottom end of medium-mass. I would not put this cartridge on a low-mass arm for fear of diminishing the bass output. Due to the apparent delicacy of the cantilever, I would also be very reluctant to use it on a high-mass arm.

Load Impedance

The impedance presented to an MC cartridge by the phono pre-amp has a significant effect on its sound. Some phono pre-amps allow this impedance to be adjusted. Audio Technica recommend an impedance greater than or equal to 100Ω for this cartridge. I have found the sound to be ill-defined at low impedances and I use 47kΩ, the highest impedance setting of my pre-amp.

Output Level

The cartridge has a quoted output level of 0.4mV (at 1kHz), which is not especially high for an MC cartridge. My phono pre-amp has a gain of around 56dB for MC cartridges, which is again not particularly high. As a result, I must turn the volume control on my amplifier significantly higher than when using a typical MM cartridge. I would therefore recommend that a phono pre-amp with MC gain greater than 56dB be used with this cartridge.

Comparison

I don’t have another low-output MC cartridge to compare with the AT-OC9ML/II, although it shares a mellow overall sound with my high-output MC cartridge, the much cheaper Denon DL-110. The Denon perhaps has a slightly warmer balance with a little more body supplied by a chunkier bass, but it does not have the same finesse in the treble and midrange as the AT.

My closest MM cartridge in terms of price is the Goldring 2400 and the sound of this cartridge is not dissimilar to that of the AT-OC9ML/II – they are both well-balanced and have a refined, mellow quality. The AT, however, pips the Goldring on treble refinement while the Goldring may have the edge in the bass. Above all, the AT has far superior tracking ability over the Goldring. The advantage of the Golding is that the stylus is replaceable (it is not on the AT and most other MC cartridges) and its cantilever is easier to see, making stylus cleaning less of an ordeal.

Summary

The AT-OC9ML/II pretty much met the expectations of my first genuine MC experience, with its highly refined sound, particularly through its clear and delicate treble. It also has a nicely integrated sound that is not going to tire the listener, although sometimes I wish it had just a bit more bass oomph. A notable advantage of this particular cartridge is its very fine tracking ability and the exceptionally clean presentation that results. Is it worth the money over cheaper options, particularly MM cartridges? For those with sensitive ears, yes! I mean this in two senses – for those who can appreciate the subtleties of good sound reproduction and for those who are easily offended by the rough edges of some cheaper cartridges. However, it is true to say that some of my MM cartridges can produce a more dynamic and entertaining performance. From my limited experience of MC cartridges, I can certainly recommend the AT-OC9ML/II, purely from the benefit of its MicroLine stylus.