LONDON Decca, Tzar DST and similar cartridges

normansizemore
I have the Decca London, and use it with a Grace 747 tonearm. Everything you’ve read is true. It has a unique sonic presentation, and I haven’t found anything that it doesn’t play well.

Some other arms people have found to work well with Deccas and Londons: The Arm by David Fletcher (designer of the original SOTA table); Mission Mechanic (a U.K. arm similar to The Arm); Fidelity Research FR-64/66; Keith Monks (a somewhat rare U.K arm---I've never seen one for sale); Eminent Technology or other air bearing straight tracker (Kuzma perhaps?); Decca International (no surprise there, ay?! It's a unipivot, though).

The long-held common wisdom was the design liked a damped unipivot arm, which London still recommends. I really dislike them ergonomically, however (the left-to-right-"floppiness". Plus, I'm not convinced highly modulated grooves are not capable of rocking the cartridge and hence rotating the arm tube about it's center, if you see what I mean).

The other belief was that the arm should be of higher than rather lower mass, for those who, unlike halcro, believe in getting the arm/cartridge resonance to around 10-12 Hz. After discussing the matter with Robert Levi (he recommends an arm with a lower "moment of inertia", i.e. mass), I entered the mass figure of the London Reference and Rock outrigger hardware (17.5g total) into the arm/cartridge resonant frequency calculator on The Vinyl Engine site, and was surprised by the results. Any arm is going to be a compromise, as the lateral and vertical compliances of the cartridge differ (15 and 10, respectively). Straight tracking air bearing arms have different moving mass figures, but I'm not sure if it's in the right direction (lateral versus vertical), or the opposite. The calculator suggested an arm with rather low moving mass for the 17.5g figure, like 8-10g, to achieve the 10-12 HZ figure.

Whether or not one is concerned with achieving any certain resonant frequency figure, a stiff self-damped arm tube (Geoffrey Owen claims his Helius arms are self-damped by means of their differential mass design) or externally applied damping is highly advisable, and all cartridges benefit from good bearings, none more so than the Decca/London. The massive amount of mechanical energy the cartridge passes down the arm tube and into those bearings is really going to put them to the test!

The only table that is of particular appropriateness for the Decca/London is the Townshend, because of the damping trough endemic to it. One thing to be aware of is that because of the cartridge's unshielded magnets, Decca/Londons can not be used on a ferrous platter, like the one on the original version of the Thorens TD-124, though the aluminum plattered Mk.2 is fine.

As for arms for the cartridge, Ken Kessler (a long-time Decca enthusiast) is happy with the SME V, others with the Well Tempered, and the Zeta is an old favorite. Geoffrey Owen of Helius Designs in the U.K. has a fair amount of experience mating his arms with the cartridges (Robert Levi has his Reference mounted on a Helius Omega Standard), and the Kuzma's seem like they should be a good match (nice stiff tube and excellent bearings), though I haven't heard one way or the other. Art Dudley thought the Rega 300 was good enough for the Decca Maroon (spherical stylus) he just reviewed, but the cartridge deserves better. In fact, the best you can afford, just like any other great cartridge!

Art Dudley talks about the Decca cartridge in the December Stereophile (I would provide a link, if only I knew how!). His review is of an older model, and the current London's are considerably improved, from the entry-level Super Gold to the Reference. They all put out 5mV, needing no more than 40dB or so of gain, and are best loaded with 15k to 22k Ohms resistance and 220pF capacitance (which electrically damps the design's high-frequency resonance). George Couness provides a 15k Ohm input on his Zesto phono amp specifically for the Decca/London!

As halcro, I too dislike unipivots, though they are recommended for the Londons by their maker. The cartridge has no suspension to speak of, so some form of damping is found beneficial by many users. Whether the chosen arm does or does not offer damping, it had better have a very stiff arm tube and chatter-free bearings, as the Londons put a LOT of mechanical energy into the arm. As Warren Gregoire told me, any arm that's good with a contemporary mc will be fine for the London.

I prefer the cartridge to all others by such a large degree (again, as halcro said, it is by far the most alive---I like the old Gordon Holt term "immediate"---sounding design I've heard), that I picked not just my arm to best suit it, by my turntable as well. The Townshend Rock could have been designed specifically for the cartridge, as it provides mechanical damping right at the source---the headshell. A side benefit is that the Rock's "outrigger" hardware adds 11 grams mass to the cartridge's 6 grams, aiding in balancing the arm and achieving a good resonant frequency, which is tricky---the cartridge's compliance in the lateral and vertical planes differ considerably.