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Is the at 150mlx a bad match on the jmw9 tonearm

I am asking because I just installed the at150mlx on my vpi scout 1.1 and am getting woofer pumping. I had a ortofon 2m blue before this and had no pumping. The table is on a flexy style stand with 4 butcher block shelves and a laminated top shelf of 1/2" acrylic ,1/2" aluminum, 1/2" acrylic. The table sits on the top shelf on top of a sand box. The stand is spiked into carpet on a concrete slab. It is located about 12' away from the right speaker behind the listening position. I am not sure what other information would be helpful but it seems to happen at normal listening levels( slightly louder than conversation).If it is a bad match I would like to figure it out ASAP and return it for something else. Thank you for any help.
128x128wilson667
stringreen's avatar
stringreen
6,393 posts
 
Wilson...it looks like they have changed the arm since you got your table...the new ones can be damped...they come with a bottle of damping fluid. Also...I know this is an anathema, but try no anti-skate. Makes the cartridge sound better to my ears.
zd542
5,339 posts
 
"09-19-15: Stringreen
What doesn't look right to me is flexistand? Don't know what that is, but VPI's don't like flex."

Look at the pic of his rack. I think he meant plexy not flexy.
johnnyb53
3,510 posts
 

09-19-15: Wilson667
Johnnyb53 I am not sure that I want to add a headshell weight. It sounds like you are saying adding a weight of about 13 to 18 grams.that seem like an awful lot of weight to add.
No. The effective mass of the tonearm alone is 7.7g. The mass of the cartridge plus hardware adds 8.8g for a total effective mass of 16.5g. This is an unmodified effective mass, as VPI would certainly know that the cartridge is going to weigh something in that range.

So I'm talking about adding a headshell weight of 3 to 5g. VPI even makes a 3g headshell weight for JMW tonearms, so it must be OK with them too.
andrew9405
225 posts
 
It's not a good tonearm to begin with.
None of the vpi arms are really.
wilson667's avatar
wilson667 OP
93 posts
 
Hey Johnnyb53
thanks for pointing that out I totally grazed over adding the weight of the cartridge to the calculation.Is there any way to see if the added weight will work perhaps a penny and some blue tack? Another thing has got me confused Audio-Technica does their compliance calculations at 100hz and not 10hz as the calculator calls for. I have no idea how to do the conversion to the 10hz number that is required.
Andrew9405
It is not very helpful in solving my problem to tell me the arm is not very good. It is what I have to work with. I don't want this to devolve in to a debate about how good the arm is or is not.
Zd542
I did say [http://www.tnt-audio.com/clinica/flexye.html]flexy[/url] It is not quite the flexy stand outlined by tnt audio with only three legs it is more like a salamander nock off it has 4 legs and i used salamander's points for the feet.it is a very solid stand.
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