The output of my Decca London Gold Cartridge went low and when I opened it up and found that a pole piece had gone adrift. Would anyone know when this pole piece sit.
Thanks

Could you post a picture, or at least describe the situation? I'll go look in my Export to see where it should go, but I can't tell from your description which part is loose. Odd design -- even though the stylus puts more energy into the cartridge than practically any other design, the physical construction is preposterously flimsy. Amazing how great they sound when things are right, but its not amazing how variable they are.
But I have to reiterate so people who haven't heard them don't get the wrong impression -- its amazing how great they can sound!

Hi,
I will try my best to describe:
1. CArtridge is a moving iron design with 3 coils. One sits right angle to the stylus with the moving iron part going thro' the coil's contre hole. A piece of moving iron is mounted at the other end of the stylus tip. So the assy looks like a spear with moving iron as the handle part. One can see this coil without opening up.
2. Cartridge can be opened quite easily by lifted its lid. Can see 2 more coils sitting horizontally at either side of the centre. A 'V ' shaped armature goes through the centre of the 2 coils. Together with the moving iron element just described, the whole armature is a 'Y' shape, with the moving iron part moving, sitting close but non touching the V part. The 3 coils mentioned earlier whose contre passes through each of the ' Y '.
3. There are 3 pole pieces - 2 that is in the first coil assy, that can be seen without opening up sitting either side of the coil.
4. It is the third pole piece that came adrift, it is related to the 2 coils and the 'V' part of the armature.

The Decca London Gold cartridge is a wonderful one if one can set it up right. The best reproducer for Jazz and percussion type of sound, so lifelike. No a good tracker though.

It sounds to me like you may be describing the magnet. Its a square block that sits between the two iron polepieces that the coils are wrapped around. Its held in place solely by magnetic attraction and can be pushed out of place , or if the cartridge were dropped it might shift. I believe its supposed to be in contact with the polepieces as symmetrically as possible.
I am trying to post a picture, but the file is too large, and I haven't figured out how to do it.

Yes, that is the magnet I refer to - it is free to move and I don't know where it should sit.

The rectangular magnet fits right inbetween the two cylindrical pole pieces that stick up out of the two coils visible from the top. It is in physical contact with both of them, and magnetic attraction holds it in place. I believe the pole pieces should contact it in the middle of the side of the magnet. I think that the magnet is alnico or maybe neodymium or some rare earth magnet, so it is surprisingly powerful, and may be not so easy to move into place, and obviously steel pliers or tweezers are probably not a good idea. I would be careful about all the wires that are haphazardly bent all around -- they might offer a chance to short out the signal even though they are insulated with varnish -- if the magnet has been roaming about, it might have scraped some of it off.
And its always worth checking to see that the tonearm leads don't contact each other -- its pretty tight back there.
I wonder if a bit of white glue might help damp out resonances in the magnet and coils and in all the various plastic pieces that are simply trapped in place. I thought it helped the case to run a small bead of glue along all the seams. The case is actually simply held on by pressure and the glued on Decca Label (!), and the glue seemed to give a bit of structural integrity. And of course, its easily reversible. But I have not tried glue inside.
Its amazing that this cartridge, which must put more energy into the body than any other, is so pitifully constructed, yet can sound so good...

Hi Nat,
Got the cartridge working again after reading your Mail! I also found out that the orientation of the poles of this magnet is of utmost importance, wrong N-S orientation will result in mono working only.
I love the Decca sound too, so vivid, but I guess it is partly due to the characteristics of moving iron principle. Had the B$O SP1 in the long gone past and the MM6000 in my current B&O 4002, both cartridges offered more lively sound than the MM ones.
Many thanks for your help.

Glad you are back in business. The n/s orientation issue you mention is interesting -- I also have a non export london -- blue case, and it only has one channel -- do both channels work in mono when the magnet is backwards or does only one channel? It would be great if wrong magnet orientation was the only thing wrong with it. Thanks for the tip.

Both channel carries the same mono sound, in case of wrong N-S orientation. If only one channel have sound, then almost certain that it is some wiring came loose.