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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.
wilson667
andrew9405
225 posts
 
It's not a good tonearm to begin with.
None of the vpi arms are really.
wilson667's avatar
wilson667 OP
90 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.
johnnyb53
3,490 posts
 
I knew somebody used a different frequency for its compliance calculation,
but forgot that it's AT. For that you might ask a customer service rep at
LpGear how the 100Hz spec translates at 10 Hz. It could be that your
compliance is spot on and something else is amiss.

When you think about it, a high amplitude cart/arm resonance in the 12 Hz
range would cause the woofer to flutter rather than pump, as the woofer
excursions would be 1/12th of a second apart. Visible woofer pumping
would occur at a few Hz (e.g., 5) or less, more like 1 or 2 Hz.

So maybe this is related to 33-1/3 rpm, which, if eccentric, would be about
1.8 Hz, ideal for visible pumping.

So what could cause eccentric tracking? I could guess a few:

o Antiskate out of adjustment
o Record with off-center hole
o Cartridge azimuth out of alignment
o Tracking weight too high
o Belt stretched and needs replacing
o Platter bearing needs lubrication
o Turntable not absolutely level
o Maybe even VTA or SRA setting

Something along those lines.
zd542
5,339 posts
 
"I did say [www.tnt-audio]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.
Wilson667 (System | Threads | Answers | This Thread)"

I see it now. The top shelf looks like plexiglass, so that's where I got the idea from. I have 2 Scouts and one of them is on a stand similar to this. Its one of the ones that Michael Green designed and sold through The Cable Co. I've never had any problem like this with either one. The only real difference I can see is that I use lower output MC carts, but I don't see why that would make a difference. Of all the answers so far, Johnnb53's seem to be the most plausible.
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