These are a unique moving iron design, which mimics most closely the mastering of the LP with a cutting head. Here is first a side view and then a frontal view of the generator assembly. It has "vertical right angled cantilever", which is hinged at the back. Like most cartridges, it has two lateral coils, but unusually it only has one vertical coil.
The original catridges were called FFSS (Full Frequency Stereo Sound), to go with the FFSS records, which Decca produced at the time. The first 4 iterations (Mark I - IV) came with a speciall integrated headshell, which had a special Decca fitting (on the Decca International arm). There was a SME adapter made to allow these to be fitted to a standard SME tonearm.
With the Mark IV, they also produced cartridges with a standard 1/2 inch fitting, so that they could be mounted on any tonearm. These were the RC4 (conical tip), C4E (elliptical tip) and the SC4E (specially selected C4E).
The Mark V is also commonly known as the Blue (domestic) and Grey (export version) and introduced the plastic mount, which continues with the Mark Vi (Maroon, Gold and Super Gold).
Until recently, the Decca cartridge mounts had only 3 pins (rather than 4), so the ground from the two channels on the tonearm leads need to be attached to the single ground pin. Sometimes, you might get away with attaching only one lead and leaving the other ground lead free.
The Decca brand was sold to Tatung electronics (I think) when the Decca Special Products department folded back in the late 80s. John Wright, who worked at Decca SP, then bought the rights to the cartridges and started to make them under the London brand. JW then went on to refine the cartridges, producing first the Jubilee and then the Reference.
They are high output cartridges and will go straight into a standard MM phono input. A 47k loading is fine, but some say it works better on a 33k loading (which I have).
Sound wise, they are probably the most live sounding cartridge ever made. They can sound a bit edgy at times, if not properly set up. There are stories about Deccas ripping up the grooves in your LPs. These are fairy tales. I have been using deccas for 35 years and not had any problems, which might not be associated with poor care (eg using dirty stylus, poor set up, worn tip etc).
