Why Use a Dedicated Mono Cartridge? A Guide to Miyajima Kotetu, Spirit, Zero and INFINITY MONO
A stereo cartridge can reproduce a mono record, but Miyajima Laboratory takes a much more specialized approach: it manufactures cartridges intended specifically for monaural LPs.
The distinction matters because Miyajima's dedicated mono models are mechanically designed around lateral groove modulation and are not intended for stereo records. The manufacturer explicitly warns that its vertical-axis-concentration mono cartridges should not be used to play stereo or Duophonic LPs.
For a collector with a serious library of mono pressings, that makes a dedicated mono arm or removable-headshell setup more than an audiophile curiosity.
What Makes Miyajima's Mono Design Different?
Miyajima calls its approach the "vertical axis concentration method." According to the manufacturer, the mono cartridge is designed so that the stylus responds to the lateral modulation of a mono groove without the vertical movement required for stereo playback.
Miyajima also states that modern mono reissues cut on stereo cutting equipment can be used with its mono cartridges when the groove contains only horizontal modulation.
The important warning is equally clear: these cartridges are not for stereo LPs.
Kotetu MONO: The Entry Point
The Kotetu MONO is the lightest model in this group.
Miyajima currently specifies:
Weight: approximately 6.4 g
Impedance: approximately 4 ohms
Output: approximately 0.3 mV
Compliance at 10 Hz: around 8 x 10^-6 cm/dyne
Tracking force: 3.0-4.5 g, with 3.5 g recommended
Stylus: 0.4 x 0.7 mil bonded elliptical diamond
Miyajima states that the Kotetu uses the same basic structure as the Spirit and the discontinued Premium line, with the model created to provide the mono design at a lower price.
Spirit MONO: Low- and High-Output Options
The Spirit MONO broadens the system-matching options because Miyajima offers both standard and high-output versions.
For the standard Spirit MONO, the manufacturer specifies approximately 5 ohms impedance and approximately 0.5 mV output. The Spirit MONO high is specified at approximately 90 ohms and approximately 5.0 mV output.
That difference is important for phono-stage matching. A 0.5 mV moving-coil output and a 5.0 mV high-output cartridge do not make the same demands on gain.
The body weighs approximately 9 g and the recommended tracking force is 3.5 g. The MONO stylus is a 0.4 x 0.7 mil bonded elliptical diamond.
Zero MONO: Different Stylus Choices for Different Eras
The Zero MONO uses an African Blackwood body and is specified at approximately 10.2 g, 6 ohms and 0.4 mV output.
It is available with either a 0.7 mil or 1.0 mil pure conical diamond stylus.
Miyajima's guidance is unusually specific: the manufacturer recommends 0.7 mil for reissue mono LPs and mono LPs after 1960, while 1.0 mil is recommended primarily for deep-groove first pressings from the 1950s. Miyajima also states that both sizes can trace mono LPs from all generations, with 0.7 mil the recommended all-round choice.
That is exactly the kind of detail that should come from the cartridge manufacturer rather than from a generic vinyl guide.
INFINITY MONO: Check Tonearm and Headshell Compatibility
The INFINITY MONO is physically much larger and heavier.
Miyajima specifies:
Weight: approximately 14.8 g
Body dimensions: 24.0 x 28.6 mm excluding terminals
Tracking force: 3.0-4.0 g, with 3.5 g recommended
Impedance: approximately 6 ohms
Output: approximately 0.4 mV
Stylus: 0.7 or 1.0 mil pure conical diamond
The manufacturer specifically tells users to check whether the cartridge can be used with their tonearm or headshell because of its size and weight.
That warning should be taken seriously. Cartridge mass, counterweight range, headshell clearance and arm geometry all need to be checked before purchase.
What About 78 rpm Records?
Miyajima offers separate 78 rpm versions of several mono models.
The manufacturer's current guidance identifies 3 mil as the basic stylus size for most 78 rpm records and 4 mil as suitable for certain older 10-inch 78 rpm wire recordings from around 1925.
A 78 rpm collection therefore deserves its own cartridge/stylus decision rather than assuming that a mono LP stylus is suitable.
Do You Need a Second Tonearm?
Not necessarily, but it can make a serious analogue system much easier to use.
If a turntable has multiple armboards, a second arm can remain permanently aligned for mono. Another practical option is a tonearm with a removable headshell, provided alignment and tracking parameters are handled correctly.
The advantage is convenience: a collector can move between stereo and mono playback without repeatedly reinstalling cartridges.
FAQs
Can a Miyajima MONO cartridge play stereo records?
No. Miyajima explicitly warns against using its vertical-axis-concentration mono cartridges on stereo or Duophonic LPs.
What is the output of the Miyajima Zero MONO?
Approximately 0.4 mV according to Miyajima.
What stylus should I choose for 1950s deep-groove mono LPs?
For the Zero and INFINITY MONO, Miyajima recommends the 1.0 mil stylus primarily for deep-groove first pressings from the 1950s.
Is the Spirit MONO available in high output?
Yes. Miyajima specifies the Spirit MONO high at approximately 5.0 mV output.
Conclusion
A dedicated mono cartridge is a specialist tool, and Miyajima's range makes that specialization explicit.
Kotetu offers the most accessible route into the concept, Spirit adds low- and high-output choices, Zero introduces stylus options tailored to different mono eras, and INFINITY requires more careful tonearm compatibility because of its physical size and weight.
For collectors with important mono pressings, the correct cartridge, stylus and phono-stage match can turn mono replay into a purpose-built part of the system rather than an afterthought.
LINKS:
- Explore vinyl playback equipment at Simco Audio
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- Contact Simco Audio for mono cartridge and phono-stage matching