MM cartridges

Oops, sorry for hijacking the thread. I shan't do it again mates!

Dover and Dougdeacon, what is it about the Audiomods arm that makes it unsuitable for use with Decca/London cartridges? The common wisdom has always been that they like damped unipivots, but London importer Warren Gregoire tells me they actually require a stiff arm tube and good bearings, both of which the Audiomods arm possesses. As to effective mass, the compliance of the cartridges is 10X10-6cm/dyne vertical and 15X10-6cm/dyne lateral, which requires an arm of medium mass to get the arm/cartridge resonance around 10Hz. The Audiomods can be had with a counterweight of several different masses, one of which will enable that figure to be reached. Are there other considerations than those I've mentioned?

Great Dover, thanks for all the info. The Kuzma Stogi Reference looks like it might be able to handle all the physical energy the Londons (or other low-compliance designs) throw into an arm. The arm tube is pretty massive (similar in shape to the SME V), and Frank's bearings appear to be respectable, though they are only common carbon steel of a good but not excellent grade. Have you mounted a Decca/London on a Reference?

Powder1, the "pod" is called Deccapod, and is a thick chunk of aluminum machined in the exact shape of the Gold/Super Gold body. It replaces the standard flimsy plastic mounting bracket (which is a joke and should be done away with, the Deccapod becoming standard), rather than being added to it. It becomes the new top of the cartridge (with threaded holes for mounting the cartridge to a pickup arm), and does indeed damp the cartridge (but not by damping "the energy between tone arm and cartridge"---read on); without it the thin tin body is unsupported and free to resonate like crazy (you can hear the record even with your pre-amp muted!), and very microphonic. It also stiffens the whole cartridge assembly and facilitates the passing of the massive amounts (for a cartridge) of physical energy the cartridge produces into the pickup arm, making the stiffness of the arm's tube and quality of it's bearings even more important. The Deccapod's extra cost is definitely justified---I would go so far as to say a Gold or SG should not be purchased without it. The Jubilee and Reference London's don't need it (because of their different bodies), and in fact can't accommodate it.

Thanks Pryso. I put in a call to Scot Markwell at Elite Audio, the U.S. distributor for Kuzma. The Stogi Reference is available with a number of upgrades (silver wire, etc.). The more I look into it, the better it looks. Dick Olsher really likes the 12" version, and his taste and mine are consistently aligned.

Right Pryso, Kuzma arms come standard with continuous wiring from cartridge clips-to-Eichmann Copper Bullet RCA plugs (THE way to do it, IMO), with a choice of copper or silver (at extra cost). Robert Levi has his London Reference on a copper wired Helius Omega, feeling silver wire will be too brash with the London. My phono and line stages are both tube (as is my power amp), so either will probably be fine, silver providing a little more resolution and low-level detail. Powder1, the Audiomods arm is also available with copper or silver---which does yours have?

The choice of wire may be a recent development. It's not mentioned anywhere on the Kuzma site, I only learned of it when speaking with Scot Markwell. Silver wire increases the price of the arm quite a bit, more than seems justifiable. There's nothing "wrong" with copper wire, after all! But I'm glad arm makers are starting to do the internal wiring in one continuous piece, from cartridge clips to RCA plugs. It's standard on all Kuzma arms, and an option with both Audiomods and Helius.