Decca carts

If by Decca you literally mean a Decca-labeled cartridge, you are taking a huge chance. They haven't been made for years, Decca itself selling the company in 1989 to Decca engineer John Wright. Even when new they were unbelievably variable in quality, some being fine, others complete pieces of junk. I know, I had some. When buying used, you have no idea what you're getting.

If, on the other hand, you actually mean a London cartridge, that's a very different proposition. JW, who builds each and every London, took it upon himself to do it right after buying the rights to it's manufacture, and current London's are magnificent! But be forewarned---they are a very idiosyncratic, demanding pickup. You can't just mount one in any ol' arm, plug the arm's cable into any ol' phono stage, and use it like any other cartridge. They require a certain kind of arm, have to be capacitance and resistive loaded, and used in a certain kind of way. One false move---a record rotated in the opposite direction with the stylus in the groove---and you have just destroyed the cartridge.

There is much more to say about Decca/London's; you should thoroughly research the cartridge before even considering getting one. They can provide the best sound you've ever heard from LP's, but they can also be the worst!  

Ah, fourwinds, you went through the Warren Gregoire "interview" ;-) ! A 12" unipivot sounds like a fine arm choice; London’s throwing a lot of mechanical energy back into whatever it’s mounted on, and can cause any but the best bearings to rattle. Warren told me the current London’s need the same arm as any other high-quality cartridge---medium effective mass, a stiff arm tube, and good bearings.

The owners manual with the current London’s gives recommendations for resistive and capacitance loading. I believe the Super Gold is spec’ed at 22k ohms resistance and 220pF capacitance, but some owners prefer the standard 47k ohms. Another thing to keep in mind is that the Londons put out a very high 5mV, so a phono amp with very high overload characteristics is a real good idea. They need no more than 40dB gain, and low-gain phono circuits typically have higher overload margins than do higher-gain circuits, a happy coincidence.

What the London provides in spades, even in comparison with far more expensive pickups, is an extremely dynamic, immediate, "live" sound, making many others sound anemic, bland, restrained. Boring!