Help with Tonearm/Cartridge Compatibility

 

Silver Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 772
Registered: Dec-07
Awhile back, Jan posted a link to a tonearm and cartridge database where you could check resonance and compatibility of arms and carts. I am trying to check the compatibility of a VPI JMW 9 tonearm with a Clearaudio Beta S Aurum (wood) cartridge. My problem is I cannot find the compliance for the cart. It seems to be on the light side for the arm. What I do have:

Arm effective mass: 7.7 g
Cart weight: 6 g
Tracking force: 2 g

Arm shows range of 7-12 grams for cart. By contrast, the JMW 9 signature arm (9.9 g effective mass) has a range of 5-12 g for the cart. Seems like the stainless cart at 10 grams would be a better match for the lighter VPI arm? Thoughts?
 

Gold Member
Username: Mike3

Wylie, Tx USA

Post Number: 2062
Registered: May-06
The first part of the post you seem to have answered your own question.

The arm is more critical to your sound than the cartridge FWIW, so if all is relative to your budget I would upgrade there first.

My thoughts? Why Clearaudio?
 

Silver Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 777
Registered: Dec-07
MW,

http://www.audiogon.com/cgi-bin/cls.pl?anlgtabl&1252162232&/VPI-Scoutmaster-with -JMW-9-ton

Trying the gage whether the combo is worth a further look. Not sure it is very compatible, so wanted to check using tool JV had submitted before, but did not have all the specs to do so.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 13738
Registered: May-04
.

He's asking about the mechanical match between the arm and a specific cartridge, i.e. where the resonance of the system will fall.

Here's the link to the database; http://www.cartridgedb.com/


I don't understand this sentence, "Seems like the stainless cart at 10 grams would be a better match for the lighter VPI arm?"

A "stainless" cartridge? I know VPI has a stainless steel arm but I was not aware of anyone building a stainless steel body for their cartridge.



You want to stay as close to the "ideal" center of arm/cartridge pairings as possible. Straying a bit to one side or the other will move the system resonance up or down depending on the direction the pairing falls. Higher resonance is normally the more destructive of the two since this pushes the resonance up towards warp/off-center frequencies and means the pair will have less success faithfully tracking discs that are in bad shape.

It's a fair assumption that virtually all LP's have some degree of warp (watch your woofers when you play a disc, they probably bobble in and out no matter the quality of the disc) and most mass market discs will be slightly off center. You know how many and to what degree you have warped LP's in your collection. A record clamp or outer ring will minimize any warps and make the arm/cartridge match a bit less relevant. Matching the two pieces together results in less wasted energy (wattage/woofer motion) as the resonance is decreased in amplitude. The more the woofers stand still while tracking an LP the more energy is being used driving the system with the information in the grooves and not from the warp.


You can search the database for exact numbers but I would guess the ClearAudio cartridges are all medium compliance designs. That and medium mass tend to be in the majority in today's market.



.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 13741
Registered: May-04
.

One important advantage of the Signature arm would be its damping system, which is not to my knowledge available on the lower priced version. The viscous damping system will work to stretch the acceptable range of cartidge matches. It also minimizes the uni-pivot bearing's wobble which can be somewhat disconcerting until you get used to its movement. The result is smoother, more consistent perfomance across the disc.

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Silver Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 781
Registered: Dec-07
Jan, thanks for the info. The signature arm also has higher mass, which I think extends the lower range. They show 5-12 grams for the cartridge for the signature arm, and 7-12 grams for the straight JMW 9.

The subject cart comes in wood (6 g) or SS (10 g). The pic in the audiogon ad shows it as wood.

http://www.needledoctor.com/Clearaudio-Aurum-Beta-S?sc=2&category=367
 

Platinum Member
Username: Nuck

Post Number: 12939
Registered: Dec-04
I still did not get to weigh the mounting screws, which are part of one calculation.
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