If you are thinking of getting your stylus reconditioned then it would be well worth your time to read this outline of stylus specifications to help you make the right choice...
This gives info on specific specifications offered while also trying to give a good overall understanding of stylus specifications as there is lot of confusion over the subject.
This is well worth reading through carefully, paying attention to details such as the useful life. The spec you choose will depend on your usage and budget. The different specs offer different levels of audio fidelity and different useful lives. The useful life is how many hours of use it will last before wear of the diamond has reached a point where it is not advisable to use it anymore; using it past this point will cause record damage and distortion.
It is recommended to replace the stylus well before noticeable distortion occurs, because if you wait for noticeable distortion you will have already damaged your records. All useful life’s are given as maximum useful life, this is because if your records or styli are dirty this will significantly increase stylus wear by increasing friction between the diamond and record surface. Also having the wrong tracking weight either too high or too low, both will increase stylus wear.
This is a basic stylus type and the most common, it will be the original stylus of many systems. The main drawback of this stylus type is that it is unable to accurately reproduce some of the higher frequencies, i.e. adds some distortions, particularly evident on classical music, none the less many people are perfectly happy with these styli. This specification is not usually offered because elliptical is a vast improvement.
Useful life: 1000 hours under ideal conditions.
This is a spherical diamond that has some of the front and back ground off, this allows the diamond to more accurately reproduce high frequencies The upgrade to elliptical is quite evident in sound quality in the vast majority of systems.
Closest to original B&O cartridge spec: SP12 MMC20E MMC5 MMC4 (significant upgrade from SP14 SP10 MMC20S)
Useful life: 1000 hours under ideal conditions
This is one of the line contact designs it allows the diamond to more accurately reproduce high frequencies, in comparison to the elliptical design, it has more contact area, and is able to track with slightly less force. This represents a further upgrade in sound quality over the Elliptical. In addition it lasts longer.
Closest to original B&O cartridge spec: MMC3 MMC20EN MMC5000
Useful life: 2000 hours under ideal conditions
Micro Ridge is an advancement of the contact line design. It lasts about 2x longer than contact line styli such as the MMC1. Boron is better than sapphire for audio quality due to being harder. It measures 9.5 Mohs with diamond at 10 Mohs and sapphire at 9 Mohs. Since it is harder than sapphire it is also much less likely to break in the event of an accident. This specification surpasses all original Bang and Olufsen designs.
Closest to original B&O cartridge spec: MMC1 MMC2 MMC20cl MMC6000, this specs surpasses original spec of any B&O cartridge.
Useful life: 4000 hours under ideal conditions
The same as above with the improvement of having a diamond cantilever this is harder than boron which gives an increase in audio quality.
Useful life: 4000 hours under ideal conditions
Please note you are not required to do these tests as each cartridge will be tested on arrival and you will be informed if your cartridge has a fault. However if you want to test them yourself, then here is how to do it;
Every stereo phono cartridge has two coils one for each channel. The best way to test that these coils are functioning as intended is to use an ohmmeter to test the resistance. Each coil should measure about the same as the other. If both are the same or similar resistance then the coils are fine.
For B&O styli and cartridges this method can be applied for the MMC1-5 cartridge, the resistance should be approximately 700-800 ohms for this series. The two opposing pins are one coil and the other two opposing pins are the other coil. If both coils measure about the same resistance then it's fine.
For other cartridges, the resistance varies but this method can be applied to any stereo phono cartridge. Or if you are able to play a record and audio comes from both channels as long as your system is all working correctly and mono is not engaged then both coils are fine.
For the MMC20xx and MMCx000, these are difficult to test as the contacts are hard to get to. The easiest method is to use one of the ¼ inch adapters to make the contacts easier to test. If you do not have one of these then you can use thin probes to test inside. For this series, the two furthest to the right are one coil, and the two furthest to the left are the other coil. The resistance should be approximately 700-800 ohms for each coil.