What innovative, unconventional cartridge designs can you recommend?
Most cartridges have a stylus and cantilever where the transducer (magnet, iron or coil) sits on the far end of the cantilever. What other designs are there?
I am mindful of two designs which put the business end right on top of the stylus. The first is the moving coil (MC) Audio Technica AT-ART1000 which places two tiny coils, each 0.9-mm diameter, with eight turns of wire directly above the stylus. Australian price is about AUD-7000 and there apparently is a newer model, slightly less exxe. the ART1000X. This has square coils for a bit more output, and threaded mounting holes.
A downside is that stylus replacement involves a factory maintenance program and the Australian website page describing this service does not exist.
Another design is optical, exemplified by DS Audio's range. While these still need a stylus to trace the groove, the signal is produced by reading the intensity of light produced by a Light Emitting Diode (LED) hitting two sensors. Between the LED and the sensors are two 'shades' mounted above the stylus which change the amount of light as the stylus vibrates. These cartridges need a special "photo-stage" to replace the conventional phono-stage which is an additional expense.
Australian prices including photo-stages range from AUD-2,150 for the DS-E1 to the DS Master 3 at approximately AUD-40,800, which is a bit outside my price range! Where is the sweet spot?
What other way-out designs are there?
There is a stylus wear test being performed by Ray Parkhurst over at the Vinyl-Engine with some very interesting results; it's a 30-page thread, but starting at this page will give some insight - SWS3: Stylus Wear Study 3 - Page 24- Vinyl Engine. The whole concept of the stylus bottoming is now being analyzed with the details showing that records are cut differently which can impact when the stylus bottoms-out. There is a lot to digest. |
I am writing this before diving into @antinn 's references but here's my back of the envelope thoughts! One ton is about 1000-kgs, and pressures used to often be stated in tons per square inch. For example, mild steel had a tensile strength of about 40 tons per square inch (before SI forced the Pascal on us). So one ton is a million grams, and the pressure of one ton/sq in = the pressure of one gram per millionth of a square inch. The same as a square with sides a thousandth of an inch. There are about 25 mm to an inch, so 25-microns per side. The half-wavelength of a 20-kHz tone towards the inner limit of a record is about 5 microns. The combined length of both groove walls is about 50-microns. A line stylus with a downforce of 1 gram, that completely fills a half wavelength, would exert about 25 / 5 x 25 / 50 or about 2.5 tons per square inch. Double the downforce and you get 5 tons per square inch. Change to a less filling stylus shape, and the numbers go up again |
richardbrand OP
"Thanks for the need for a SUT in addition to my MC input." Noooooo, you need one or the other, not both. An MC Input typically has enough gain for LOMC Low Output Moving Coil cartridges, (that would include the 0.22mv of the ART1000x) and they also include RIAA Equalization, the end result is a LINE level signal. SUT Step Up Transformers are used to simply pre-boost the signal strength enough to use a typical MM Moving Magnet Input, which then performs both some boost and RIAA Equalization. RIAA Equalization must occur somewhere, but not twice. |
