JMW 12.5 Tonearm helpppp (Southern Callifornia)

shaizada · « **on:** 24 Jun 2009, 04:49 pm »

Hey guys,

My rig has landed. Now, I am completely overwhelmed by this thing.

I've put up the basic pieces, and the motor is spinning the platter fine. Now comes the arm.

The cartridge is pre-mounted on the arm. The issue is that the arm seems to be tilted inwards a bit. I'm trying to read the manual, but I'm just not going to get anywhere by myself. I'm extremely wanting to learn this stuff, but I need some sort of guide / teacher.

Is there anyone in the Southern California region who would like to help me at my place?

Basically I want to make sure all the settings are correct before the first time the needle gets dropped. You have no idea how much torture it is to see such a piece sitting right here and my inability to play a record.

Helpppppp please!

I'm home all this week so anytime would be great....I'll work with your schedule

Mike B. · « **Reply #1 on:** 24 Jun 2009, 05:27 pm »

jeez, if the picture is not distorted it really is leaning inward. I hope you find someone who can help

kgturner · « **Reply #2 on:** 24 Jun 2009, 05:48 pm »

i'm not clear on what you mean by leaning. do you mean that the cartridge/needle aren't perpendicular to the record? i believe this is referred to as azimuth. try rotating the counter weight on the back of the arm to the left or right. looking at your picture, it appears you may want to turn the weight counter clockwise.

kevin t

Sonny · « **Reply #3 on:** 24 Jun 2009, 05:57 pm »

I have a VPI as well. I think what you're talking about is the "azimuth", which, based on how VPI set it up, it's a matter of how you twist the Lemo Connector.
That's the problem right there. If you unhook the Lemo Connector (the one that comes from the tonearm into the RCA Box) and give it one full twist (looks like you need to go clockwise) and that should fix it. if not, twist it back the other way (original) then give it one full twist counter clockwise.

What could happen is that at set up from VPI, they set the azimuth and ant-skating based on the twist they had, but you could have twisted one way or another...so try that first. if all else fails, you can give me a call or email me and I can help.

Tuan

PS pm me and i can give you my number.

Sonny · « **Reply #4 on:** 24 Jun 2009, 05:59 pm »

basically, it looks like the twist is too tight, loosen it one revolution!

kgturner · « **Reply #5 on:** 24 Jun 2009, 06:08 pm »

i'm not familiar with the jmw-12.5, but on my jmw-9, azimuth is set by rotating the counterweight. anti-skating is set by the twists in the lemo connector. whether or not the jmw-12.5 azimuth is set by twists, it does appear that his lemo connector is twisted a bit tight from the picture.

per the 12.6 tonearm manual (http://www.vpiindustries.com/pdf/JMW_12.6_Manual.pdf), azimuth is set by rotating the counterweight. unfortunately, there is no setup manual for the 12.5 arm. the manual for the 12 arm mentions an azimuth ring which i don't believe is present on the 12.5 arm.

kevin t

Sonny · « **Reply #6 on:** 24 Jun 2009, 06:17 pm »

Kevin, you are right about the Azimuth setting, but what I mean to say is that since VPI set it up...I am sure they had already set the azimuth, therefore, if he loosens the twist, he should be fine.

Tuan

Quote from: kgturner on 24 Jun 2009, 06:08 pm

i'm not familiar with the jmw-12.5, but on my jmw-9, azimuth is set by rotating the counterweight. anti-skating is set by the twists in the lemo connector. whether or not the jmw-12.5 azimuth is set by twists, it does appear that his lemo connector is twisted a bit tight from the picture.

kevin t

shaizada · « **Reply #7 on:** 24 Jun 2009, 06:27 pm »

Guys,

This is one of the first turntables that I am handling in my life, that's what kinda has me cornered.

A little newbie carelessness on my part and I might ruin a perfectly new cartridge. It doesn't help that the cartridge is a very expensive Clearaudio Accurate Moving Coil.

Darn table is sitting there without any record spinning on it....what torture!

BobRex · « **Reply #8 on:** 24 Jun 2009, 07:04 pm »

A couple of points, make sure that the tonearm is locked down when you do this, or better yet, remove it from the pivot...

The cable looks wrong, there should be a loop from the top of the tone arm to the junction box. Remove the cable from the junction box (you should have done this already if you removed the arm) and make sure the cable isn't crimped. Untwist the cable and make make sure it goes up from the tone arm and loosely curves down and back to the junction box. Once you have a good loop, pull the connector and twist it once, then reinsert the connector.

If that doesn't fix it, then do this...

From the back of the tonearm, take a fine tipped marker and mark where the counterweight sits on the stub. Once that is done, loosen the set screw and remove the counterweight. Now, hold a pencil horizontally and place the counterweight on the pencil. Notice how the counterweight hangs - since the hole is offset from the center it will hang with the mass centered under the pencil. This is the position the counterweight should have had on the tone arm stud. Put the counterweight back on tone arm in it's original position, but hanging like it did on the pencil. Once that is done you will have a neutral azimuth, which SHOULD resolve the problem.

That should fix the problem. If not, you may need to visit a VPI dealer.

shaizada · « **Reply #9 on:** 24 Jun 2009, 07:42 pm »

BobRex,

The first method worked out well. Now I have the cable doing a more natural loop and the arm now loosely moves away from the table. Here are some newer pics now:

I played with the counterweight at the back and now the arm is floating a little more laterally as opposed to being tilted in.

Wayner · « **Reply #10 on:** 24 Jun 2009, 07:49 pm »

What everyone is trying to say, but not really mentioning is that all of the VPI arms are a unipivot. They have one needle bearing pointing straight up and the whole assembly pivots on the needle point. The problem is that the arm needs to be balanced on that needle point with the cartridge mounted, the wires connected and so on. If you see the arm tilting inward, you need to "couteract" on those forces and use the mass of the counter weight to offset this. This can be done by locking the counterweight in a slightly skewed angle (from being going straight down, or hanging naturally) to being locked in an outward position (not 90 degrees but maybe 10 degrees). this will help counteract the tipping to one side. Just think of the arm as a boat. If you have all the gear on one side, the boat is going to lean to that side. Hope this helps, too. The cartridge has to be perpendicular to the record surface so this part is really important. Also recheck your VTF, 'cause you've been screwing around with the counterweight.

Wayner

shaizada · « **Reply #11 on:** 24 Jun 2009, 07:54 pm »

That helps a lot. Thank you.

I've adjusted it a little to have the arm just float. However, I think my overhang isn't right. as when the needle is dropped with the lever, it seems to go down too low. That would need adjusting with the counterweight as well.

I hate NOT knowing what to do exactly, but gotta start somewhere. I think my frustration is a little more to do with having records to spin and not spinning them. hehe

Wayner · « **Reply #12 on:** 24 Jun 2009, 07:54 pm »

To other VPI owners: I thought the round chrome cylinders on the sides of the tone arm screwed in and out, too, to help fine tune the balance. Isn't this true?

Wayner

Wayner · « **Reply #13 on:** 24 Jun 2009, 07:58 pm »

That's not called overhang. That is called VTA, or vertical tracking angle. When the needle is one the record surface, the tonearm (imaginary centerline) is suppose to be parallel with the record. I believe your model
has an adjustment that raises or lowers the entire assembly. I believe it's adjustable in the tower next to the main pivot, where the wires go into.

Overhang is the distance the stylus is from the spindle when looking down at the table.

Wayner

kgturner · « **Reply #14 on:** 24 Jun 2009, 08:55 pm »

Quote from: Wayner on 24 Jun 2009, 07:54 pm

To other VPI owners: I thought the round chrome cylinders on the sides of the tone arm screwed in and out, too, to help fine tune the balance. Isn't this true?

Wayner

wayne:

on my jmw-9, the cylinders on the side of the tone arm and attached directly to the arm. they aren't moveable. i think they are there to add mass below the pivot point, at least on my arm.

from shaizada's pictures, the cylinders appear to have a set screw on them so perhaps they are moveable on his arm.

kevin t

Wayner · « **Reply #15 on:** 24 Jun 2009, 09:17 pm »

OK Kevin, that makes sense I guess. Perhaps the arm was top heavy without the extra mass. You'd think they would make them extend outward to use a little ft/lbs (OK mm/grams) in their favor. More like a tightrope walker with a long balance bar to keep verticle. New Idea for you folks at VPI (hint, hint). Send money to:...... aa

Wayner

Sonny · « **Reply #16 on:** 24 Jun 2009, 09:28 pm »

Gaurav,

I don't think VPI could miss the overhang/set-up of the cartridge. The only way to know if the overhang or alignment is off is to put the jig on and lower it on the jig...if it does not line up with the jig, then it's off, but you have to make sure that the the jig is place on the platter with no record and that the tonearm is parallel to the platter. What you mean by overhang really is probably just VTA adjustment. Make sure that the tonearm is parallel to the record or the cartridge body is parallel to the record.

Tuan

BobRex · « **Reply #17 on:** 24 Jun 2009, 10:40 pm »

Quote from: Wayner on 24 Jun 2009, 07:54 pm

To other VPI owners: I thought the round chrome cylinders on the sides of the tone arm screwed in and out, too, to help fine tune the balance. Isn't this true?

Wayner

Maybe on the original arm, but not that I'm aware of - that was a Graham thing. From what I remember, the azimuth used to be set by rotating the ring that holds the azimuth weights. In fact, early 10s (and probably 12s) had a calibrated ring. Weisfeld has since eliminated that and now you need to shift the counterweight.

BobRex · « **Reply #18 on:** 24 Jun 2009, 10:53 pm »

Quote from: Wayner on 24 Jun 2009, 07:58 pm

That's not called overhang. That is called VTA, or vertical tracking angle. When the needle is one the record surface, the tonearm (imaginary centerline) is suppose to be parallel with the record. I believe your model
has an adjustment that raises or lowers the entire assembly. I believe it's adjustable in the tower next to the main pivot, where the wires go into.

Overhang is the distance the stylus is from the spindle when looking down at the table.

Wayner

Actually, I'm wondering if the VTF is too high. Shaizida, did the table come with a little lever type tracking force guage? If not, you need to get some sort of tracking force guage - You need to at least verify the tracking force and possiblly reset it.

Make sure you have a guage and we can walk you through the procedures.

I've got to say, for a first table you sure bought a doozy! It's a great table, but the arm (as good as it is) really wasn't designed for a beginner. It's so adjustable that screwing it up is child's play. We can walk you through the basics, but you need tools.

shaizada · « **Reply #19 on:** 25 Jun 2009, 12:21 am »

Hey Bob,

It's a catch 22 situation. I sprang for it knowing that I don't want to bother purchasing any other vinyl gear after this. This should be it for many years.

It did come with a Shure stylus force gauge.

I just leveled the table now by pumping air into the bladders (had to buy go buy a cycle pump).

Now the table AND platter are perfectly flat.

It's all about setting the arm now. I did talk with Sonny over the phone and he gave me a basic set up idea. However, actually DOING it without any knowledge is the part that just gets me.

Is there no body local who would be willing to come over?!