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Interesting difference between 12" and 9" tonearms

So I just got my 1987 Decca Super Gold cartridge back from John Wright with a Decapod fitted and new Paratrace stylus. Modified Garrard 401 with 2 arms. (see my Virtual System). I installed it in my 9" Jelco TK-850 and it didn’t sound good. Lots of surface noise and missing inner detail. I adjusted VTA and VTF and improved it some but it hadn’t a patch on the other Decca (Garrott Bros Gold with new LC stylus and Decapod) on the 12". A little irked, I tried it in the 12" version of the same arm on the same table. Same cables and armboards. Ridiculous. Transformed. Minimal surface noise. Tons of detail. Crystal clear. Musical as all hell. In fact, I can’t stop playing album after album. Ridiculous! (Cross posted from a comment on @halcro post)
128x128noromance
11 responses Add your response
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rauliruegas
13,052 posts
 
Dear @noromance  : My post was only to tell you that the 9" with that cartridge resonates at 16hz, not good match . That'a all.

In the other side each one of us like different kind of distortions and that's why you like the knife bearing.

I remember very well, because I owned, the warning that Dr. Sao Win  puts in the LOMC cartridge MC-10: don't use with knife bearing tonearms. I was owner of the SAECs 560 and 8000 knife bearings and even that are very good looking and builded with a high quality level as performers are really bad. But to each his own. No problem.

Regards and enjhoy the MUSIC NOT DISTORTIONS,
R. 
noromance's avatar
noromance OP
9,769 posts
 
Thanks @halcro .

halcro's avatar
halcro
2,664 posts
 
My LDR also performs better on my 12" FR-66S than on my 9" FR-64S or 9" DV507/II where it mistracks at several locations.....🤔Just accept it.....if you have it sounding well.....be happy 🎉🤗
noromance's avatar
noromance OP
9,769 posts
 
@millercarbon There's no cantilever on the Decca. 
@rauliruegas The 12" Jelco 850, knife bearings or not, sounds fantastic with the Decca. 
@chakster The 12" Jelco 850 sounds fantastic with all three of my Deccas. 
Gentlemen, thanks for your comments. It seems that the 9" is not a great match whereas the 12" is completely fine. I'll try it again with some mass added.
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chakster
6,144 posts
 
When i was reading about Decca cartridges i quickly learned that they are not for every tonearm, actually very limited choice of tonearms are suitable for this specific cartridge. I could not stand its design, so i never bought any Decca, the journey ended up with cantilever-less Ikeda 9 III.  
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rauliruegas
13,052 posts
 
Dear @noromance  : Your TK850 and Decca cartridge could be a not good match because the resonance frequency in between is 16hz and additional to that the Jelco comes with knife bearing that develops more resonances/distortions that gimbal bearing designs.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.
millercarbon's avatar
millercarbon
12,531 posts
 
If you listen to Lederman and some others talk about jitter, and how much "surface noise" is really internal cartridge resonances that cause the stylus to bounce around microscopically, and then think about your surface noise and everything else you heard, you’ll have your answer. Its not the length of the arm. Its the interaction of the arm and the cartridge and resonances traveling back down the cantilever to the stylus that are causing the awful sound and noise. Call it jitter. Call it mis-tracking. Either way its a problem of vibration control.
Skip about 4 min in https://www.youtube.com/watch?v=WmwnN_T_wW8&t=7s
Or skip to 13:35 for a fascinating story about this very subject.
Jitter begins at about 21:30
noromance's avatar
noromance OP
9,769 posts
 
@stringreen Set up exactly as the 12" except for overhang. They're on the same table. However, you got me thinking. The 9" has the standard Jelco base while the 12" has the Ammonite base. Could there be an azimuth issue? Would that cause surface noise? I run other Deccas without issue on the 9" but they all sound better on the 12". I wish the plinth supported 2 x 12". 
stringreen's avatar
stringreen
6,468 posts
 
..just a guess......the 9 inch wasn't set up properly.
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noromance OP
9,769 posts
 
Dan,
My guess is the additional mass of the larger arm and possibly the better tracking ability of a long arm made all the difference.
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islandmandan
1,260 posts
 
Brian, that's interesting, as even Mikey Fremer says there's no real advantage in having more than a 9" arm. I guess that's not always the case.

Regards,
Dan
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