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Does 21g seem high for effective tonearm mass?

Hi there, I've been looking into these somewhat popular Jeclo tonearms. Actually the 10" liquid dampend unit SA-750e. I've got an email from Jelco and the effective mass is 21grams. Does this not seem shockingly high compared to nearly everything else on the market these days?
I plan to mount a Sumiko Celebration on it but I'm not so sure about the match. It seems this arm may be limited to cartridge choice and that would be too bad.
If anyone can shed some light on this it would be appreciated.
My other options for arms of course would be the Rega/moths, Hadcock and I can get a pretty good deal on a VPI classic arm.
This wasn't supposed to be confusing at all as I was taking a step away from my ET2 and trying to simplify my setup. Now it seems I've opened a can of worms
alun
dcbingaman
90 posts
 
21 grams is medium mass. It will work better than all those skinny-mini 10 gram arms, especially for low-compliance cartridges.

In general higher mass arms control the cartridge instead of the other way around - am I right, Raul ??
bpoletti
1,004 posts
 
The Jelco headshell is a perfect candidate for the drill. A lot of mass can be removed without impacting the rigidity by drilling holes. I can't remember the drill pattern or how much mass was removed, but IIRC, there were a couple of people on vinylengine that pretty successful.
lewm
6,770 posts
 
To my way of thinking, 21 grams is in the range of "high mass", not "medium mass". Medium mass is more like 10 to 15 grams, IMO. Of course, to some degree it is a matter of opinion. In any case, 21 grams is not stratospherically high. Most notably, the well-liked (by some) Fidelity Research FR64 and 66 are much higher in mass. And some have mated the FR tonearms with relatively high compliance cartridges and report good results. You can easily find headshells that weigh as little as 6-8 grams, so as to effect a reduction in effective mass for the Jelco. But like Raul says, it is best to keep an open mind; don't be a slave to those formulae for mating compliance to effective mass.
bpoletti
1,004 posts
 
IMO, the classification of low, medium and high mass arms seems a bit arbitrary. The goal should be to match a given cartridge compliance with the effective arm mass. Plenty of calculators around to help in matching.
fleib
1,124 posts
 
"In general higher mass arms control the cartridge instead of the other way around - am I right, Raul ?? "

Interesting way to look at it. While the arm should provide a stable platform for the cart to track, there's a delicate balance between stability and hindrance. These days 21g is considered high mass. Most modern carts are between 15 and 22cu. The Celebration is 12cu and should be a near perfect match, compliance-wise.

Despite the Jelco sales mgr, the Jelco 750d is around 20g, so 21g for the 750e sounds about right. I suggest using as little fluid damping as possible, to preserve transient response. While good results can often be realized with compliance/mass mismatches, you'll experiment at your own risk.
Regards,
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