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JMW 12.5 ZYX Cosmos azimuth setting

I have been exploring setting azimuth on my JMW 12.5 with a Fluke DMM, Cardas test LP and the (great) MF DVD.

I'm sure I'm doing everything right but have found I need to adjust the JMW azimuth ring to a surprising degree. If you can imagine that the two 'side screws' on the ring, which when in the neutral position, are at quarter to three (on the clock), my set-up has to shift to twenty to two.

I've double checked the TT level, made sure everything' tight and the cartridge alignment is accurate. And i've got the azimuth set within 3% so I'm pretty happy about that, but feel a bit uncomfortable seeing such necessary twist of the ring!

Has anybody had a similar experience with the ring setting?

Thanks

Peter

rennie_perth
4 responses Add your response
socoaste
53 posts
 
I use the Tracking Force weight at the back for adjusting azimuth.
since the bore on the weight is off center, When
the weight is rotated to one side, the weight will
be shifted more to that side & cause the Arm to tilt
accordingly.

It's a bit tricky because you can easily slide the weight
off of your VTA adjustment. just recheck VTA as You go
to get both Azimuth & VTA dialed in.

IMO I dont believe the outriggers (when rotated) really do
much to change azimuth. when you rotate It, both of the
"Knobs" move at the same time so it is always balanced.
think about it.
rennie_perth OP
23 posts
 
Thanks for the feedback - I hadn't thought about the 'balancing knob' theory, but it seems to make sense as I need to make a major adjustment for little gain.

On the use of the counterweight; my 12.5 has a groove/channel cut in the back part of the arm tube for the c/weight locking screw, so I cant off-set it (it locks it into a central position). That's the most frustrating part, because all the commentary is about using that to set the azimuth.

I might see if I can remove those 'balancing knobs'
stringreen's avatar
stringreen
6,470 posts
 
Rennie_Perth There HAS to be a way to tilt the arm to correct for azimuth. All the new arms from VPI are adjusted by swinging the dropped counterweight. Yours is an older design. I checked the VPI website and the owners'manual is not posted for your arm. I had a ESL arm once whose azimuth was adjusted by rotating the base which was cast with a slight angle to it. Try rotating yours and/or call or write to VPI. They certainly will have the answer.
rennie_perth OP
23 posts
 
Thanks Stingreen. I have now removed the 'outrigger' fittings from the azimuth ring which makes it much more flexible it terms of adjustment.

With the outriggers in place I was struggling with the arm-lift getting in the way - not being able to twist the ring far enough. Now it's perfect - sound and balance.

I'd be interested if anybody else has tried their JMW sans outriggers. I think they'd be pleasantly surprised.
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