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Decca London Gold cartridge nightmare

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Decca London Gold cartridge nightmare

Postby razzwills » 10 Oct 2008 03:49

Having read so much about the Decca London Gold cartridge, I decided to try one. Time passed and I finally found one on ebay that was within my budget. Cartridge was guaranteed to work with good results by a seller with very good feedback. Physically the cart looked neat, and everything, except for the mounting screws, was intact.

I had intended to install the cartridge in a new Kuzma Stogi S arm on a LP12 turntable but since the arm is scheduled to arrive end Oct 2008, I decided to try the Decca on my Lenco L75, with the original Lenco arm. At least to make sure all connections were OK, if not for any other reason.

What happened afterwards was pure nightmare. The results were horrendous, to say the least!

Tell me where I went wrong.

I tried tracking between 1.5 to 3gm but the sound ranged from tinny to severe breaking up. Even more startling, the groove vibrations picked up by the stylus was transmitted to the entire headshell, so you could actually hear the sound of the grooves generated acoustically by the vibration, kind of like a diaphragm or a gramophone horn. Lightly placing my finger on the headshell while a record played confirmed this. The headshell was quaking! With the preamp gain down to zero, you could hear the headshell vibration from a distance of a foot and a half, maybe even further, I kid you not.

The cartridge that I am presently using on my Lenco is a low output Audio Technica MC, the AT-OC3. No problems there. Tracks pretty well too, but not great, considering the Lenco arm was not made for MC carts. But the results were definitely more sane than the Decca!!

What's happening? Help!

Thanks for any advice, suggestions, feedback.

beck
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Postby nat » 10 Oct 2008 15:52

The Lenco is right up there with the worst choice to use with Deccas. Because they don't have much or any damping, Deccas put a very large amount of energy into the arm, and the Lenco has knife edge bearings that rest in rubber or nylon v blocks, so any vibration can lead to rattling. The Lenco doesn't look very well balanced right and left either, so one of those knife edges may be even less tightly coupled than the other.
Deccas do very well with unipivots and with damping. You might be able to damp the Lenco, but I don't think the effort would replay itself.
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Postby markse » 11 Oct 2008 09:24

I agree with nat that the lenco arm is not a good choice for the Decca cart. It's probably just the boxy, tinny headshell that's resonating and the bearing system is really not up to the job of taming such a wild beast of a cart. I used to get the same thing on an RB300 with a super gold, and that's a pretty rigid arm compared to the Lenco! Having said that I'm having no problems with my current arm- a Thorens TP25, which doesn't look anywhere near as rigid as the Rega arm but does have good tight bearings compared with the Lenco.
It should work great in the unipivot Kuzma arm though so don't give up on it yet!
There is also a chance that the suspension is damaged- can you post a close up pic of the stylus and tie back string? If you are very careful you might try wiggling the stylus VERY gently using a wooden cocktail stick or similar (something soft that won't chip the diamond!) You should notice that the stylus is easy to move side to side and stiffer up and down, but there must be some compliance up and down. Be very careful doing this and only if you feel you have the dexterity and gentleness of touch not to accidentally snap the thing off- I don't want to be responsible for a real disaster!
(as a footnote I have found Deccas to be much more robust than some would have you believe- my current cart has snapped with its strong magnets stylus down onto a metal ruler I was using to check overhang, and been dumped unceremoniously onto the rubber platter mat several times. Despite taking years off my life in those heart stopping moments it is still beguiling me! But I was lucky and you should take real care with yours!)

Hope you persevere and get to enjoy the cart as much as I do mine,

Mark
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Postby razzwills » 11 Oct 2008 09:58

Thanks nat. Thanks markse.

I have no argument there. The Lenco L75 arm headshell feels like a tin box. It's not even heavy!

The cartridge that I am now using on the Lenco arm, a low output Audio Technica AT-OC3, also vibrates when tracking high energy passages on stereo discs. The sound this vibration produces is of course passed on to the amps.

I think the heavily damped Kuzma unipivot will be (I wait with bated breath) the perfect foil for the iconoclastic Decca.

markse—I will do the wiggle test but need to gather up courage first :lol: I did slid open the top cover for a peek inside. A bit of dust but no severe rusting or corrosion.

And yes I can take a photo but I need to charge up the camera battery first.
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Postby razzwills » 12 Oct 2008 06:14

markse—This is the closest I can get before the camera focus blurs up.
http://picasaweb.google.com/razzwill/DeccaLondonGold#[/quote]
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Postby markse » 12 Oct 2008 09:51

Hi razzwills,
it's very difficult to say from your pic but it does look like maybe the tieback string needs adjusting/replacing. If it stretches too much the armature that holds the stylus naturally springs upwards and can come to rest too close to the pole pieces inside the cart. That could mean it bottoms out on them and you literally have no vertical compliance, which would cause the problem you are experiencing. Take a look at this pic of my blue and you can just about see that the string should have an angle approaching 15deg like a regular carts cantilever:

Image

Having said that my super golds stylus was far more recessed than this blue so yours may be fine. The only way to tell is with the toothpick!

Here's another pic of the insides to help explain better:

Image

This cart had this problem and you can see (not very clearly- sorry) that there is little to no clearance between the armature and the vertical pole pieces. It's possible to adjust the clearance quite easily by adjusting those 2 tiny black screws that set the pole piece vertical spacing but the setting of that gap also influences the stereo separation so it may be best to get the cart serviced by an expert.
If you're in the UK you could send it to the Cartridge man or Presence audio to have it checked.

Good luck,
Mark
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Postby razzwills » 12 Oct 2008 14:58

Hi Mark,

I did the toothpick test. Left and right movement is about as compliant as a cantilevered stylus. Up and down is like pressing down on a firm spring. When placed on a record surface, the bottom of the cartridge body rides very close to the record surface but in no way could they be described as touching. I remember playing a warped record when I first mounted the Decca onto the Lenco and to my surprise, the Decca tracked it without skipping. And despite the severe headshell rattling and resonating, the arm did not skip like a deranged bunny all over the LP.

Does Van den Hul still service the Decca carts?

beck

p/s I'm in Malaysia.
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Postby desktop » 14 Oct 2008 18:18

Can you take a photo looking directly at the bottom of the cartridge? It would be interesting to see the alignment of the stylus with respect to the hole it fits through. Most Decca stylus/cantilevers eventually have their mounting threads go a bit slack. Then at 2.0g-2.5g tracking force or so they have no compliance at all. Getting the suspension threads fixed isn't a problem, but riding the inner bottom of the cantilever on the V block is a definite problem.
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Postby razzwills » 15 Oct 2008 02:42

desktop—The stylus tip looks almost dead centre within the 'doughnut ring'. I say almost because when I look at it head-on, the diamond tip veers ever so slightly to the left. It's an anomaly I see on cantilevered cartridges that ride in tonearms with too generous a bias setting, so the cartridge is constantly being pulled outwards. Not sure if I can apply this finding to a non-cantilevered cartridge though.

Can I?
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Postby desktop » 16 Oct 2008 18:19

In all likelihood your "sound" problem can be fixed by having Decca restring the stylus/cantilever support. They can pull the assembly "down" so that when you are looking at the stylus from the bottom view, the stylus is slightly nearer to the "rear" edge of the cartridge body, and only centers itself when tracking force is applied to the stylus assembly when the cartridge is set down on the disc. In addition by the direction of the restringing's twist and the amount of "twist tension" there is on the restringing's twist, the slight pull to one side can be corrected. At that point you will have the awesome sounding cartridge many of us love. But if you don't do this and you want to dump the cartridge if it doesn't sound great in your new arm, let me know. I have used my Deccas in many different arms and even though they don't work properly in the worst of the disco turntable arms, they do pretty well in most others.
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Decca London Gold—RIP :(

Postby razzwills » 18 Oct 2008 14:18

The worst happened. The stylus armature snapped off my Decca London Gold when I tried to blow some dust off the inside of the cartridge. The two powerful magnets came loose, landed on the stylus and rest was history.

I had actually got the Decca working on the Lenco arm, using some blu tack as damping material. It could only track mono pressings though, as stereo grooves gave it the shakes.

Some of the mono LPs I tried out actually sounded great, particularly Traffic's "Mr. Fantasy" (pink label UK Island, ILP 9061). The Beatles' "Revolver" (Parlophone PMC 7009) was pretty good too. The quiet passages on Schubert's "Tragic Overture" (Nixa, NLP 913) was sublime. When the orchestra went tutti however, it was pure horror.

I was actually contemplating capturing some of the Decca Gold sound, when it behaved, onto MP3 files and sharing it with you guys. Sadly, that will not happen.

I've spent like less than 12 hours with the Decca Gold. But what I heard truly confirmed what aficionados have always said about the Decca—When it was good, it was very, very good. When it was bad, it was horrid.

I'm not sure if I will have the cartridge rebuilt, or use the money on a saner, more predictable, hopefully not boring MC like a new Benz Gold or something.

Thanks guys for all the feedback, opinions, suggestions. It was great while it lasted.
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Postby markse » 18 Oct 2008 20:49

That's very sad news Razzwills- very sorry to hear it.
What were you blowing it out with?! Those magnets should be held quite tight by glue and their magnetic attraction to the steel casework. Is the armature actually snapped off or just damaged? You should be able to get it replaced by one of the repair people should you chose to go that route. From your description of the sound and it only working on mono records it does sound very likely that the armature was bottoming out on the pole pieces. I hope you manage to get it up and running properly- shame to abandon it having only partly hearing what it can do. How bad is the damage- do you have a picture?

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Postby desktop » 19 Oct 2008 04:03

Bad news but possibly also good news too.

As long as you didn't lose anything important, or the stylus didn't break off the cantilever armature, Decca will reassemble everything better than you've heard it thus far. The bad news is that it might cost you a couple of hundred pounds. Sometimes Decca takes a kindly interest in someone when their glues have come unglued and if they can see generally careful handling, they will be very fair. It can't hurt to try. Be sure to include a self addressed stamped envelope.
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Postby razzwills » 19 Oct 2008 11:25

Aye! But there was nothing holding the magnets or the 'doughnut' coil down. No glue, nothing. That much I was sure.

In fact I was contemplating securing the magnets and the two tiny L-shaped bits to an anchoring support after the tragedy.

A case of being wise after the event, or too little too late?

The armature broke off right where the 'bent' is. So there's a tiny piece left in the cartridge and the longer part 'outside'.

I've never known cartridges to literally fall apart. Now I'm not so sure!
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Postby nat » 23 Oct 2008 14:55

Sounds like the metal may have fatigued, perhaps because it was being stressed as a result of a loose tieback string.
My experience of various things being loose inside Deccas is the same as yours -- there may have been some glue at one point, but not enough to do much, and the magnet in mine was out of its correct place as a result, I assume of a sharp knock sometime before it came into my possession.
I have two -- one a grey and one a blue. I fixed up the grey and wore the stylus out. The stylus in the blue was unused because a coil was open, so I transferred the coils from the grey to the blue. It works, but I haven't actually listened to it -- that's coming up.
If you need a cantilever/armature, let me know. I would imagine that Decca or a retipper would have them, but if its cheaper to just replace the stylus, you're welcome to my used one.
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