Need help trouble shooting 3D arm

Re: Need help trouble shooting 3D arm

Postby Golear » Thu Dec 20, 2018 5:19 pm

I said in an earlier post that I wished there was a way to measure anti-skate force. I forgot that I did come across this:

http://www.simplyblack.net/WVC/tools/skater.htm

So whatever method you use - twisted wire/mechanical anti-skate/combination of both - you can measure the anti-skate at different spots, and make sure it's not too much or too little.

Seems like a worthwhile purchase, given how much one spends on an arm and cartridge, and so we don't damage our LPs via mistracking.

My approach is:
1. Set VTF to max recommended level.
2. Have minimal twist on the wire. And dress it so that it's a nice curve, and without kinks.
3. Set up the mechanical anti-skate as indicated in the "Modified Mechanical Anti-Skate" thread. The only variable will then be the position of the O-rings on the lower arm.
4. Adjust the O-rings on the lower arm, according to SoundSmith's method.

If you still hear mistracking on all LPs, then my view is that there's something wrong with the cartridge or the stylus. There might be uneven wear on the stylus.
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Re: Need help trouble shooting 3D arm

Postby Mr_Putty » Fri Dec 21, 2018 12:33 am

Audiom3,
Your photo shows your mechanical antiskate is not aligned correctly with your arm. The A/S mount needs to rotate clockwise about 20 degrees, viewed from the top. (The A/S line should be parallel with plane of travel of the two arms with the rubber donouts as much as possible.) This needs to be checked when the arm is near the center of a record. It’s best seen from the rear of the TT as a sight line. You will need the supplied Allen wrench to make an adjustment.
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Re: Need help trouble shooting 3D arm

Postby Bill Stevenson » Fri Dec 21, 2018 11:43 am

Follow up report:

Well my problem has resolved itself, but I am not sure what was wrong or what fixed it. I took Brf's advice and switched cartridges because I figured that any anti-skate issue would also be resolved in setting up the new arrangement. Putting the 2M Mono SE on the 3D arm worked fine. Putting the 2M Black on the metal arm also worked fine. Switching them back also worked fine. ??????? I have no idea what changed to fix the problem. I have a theory that the arm lift, which is very close to the 3D arm, might have been close enough to interfere. But it is only a theory since there is no interference now. To say the least I am frustrated.

If I were to trade up from my Prime, what VPI turntable would make the most sense? My dealer has both a used, like new TNT and an HRX on hand right now, and of course anything new is possible. This might just be talk, but right at the moment I am not loving my Prime.
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Re: Need help trouble shooting 3D arm

Postby jonathanb » Fri Dec 21, 2018 1:15 pm

Better to buy a new cartridge than a new turntable.
Prime Signature #9 | 10" 3DR/VdH RG-8 | 10" 3DR/Transfiguration Phoenix S | 10" 3D/VAS Nova Mono | Aurorasound ViDA | Gryphon XT MC | Gryphon M100 (x2) | Evolution Acoustics MicroOne | Morrow and Gryphon cables
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Re: Need help trouble shooting 3D arm

Postby Golear » Fri Dec 21, 2018 3:21 pm

audiom3 wrote:If I rotate the device as others have mentioned, it will pull the A/S device 'over the crown' and it'll fall backwards and thus, disengage. So that just doesn't work.


It's good that you moved the thread so that it is flush with the anti-skate hub, and used one O-ring. There will be minimal change in the angle that the thread makes to the horizontal plane, as the arm moves across the LP. And it precludes the upper arm from complicating things.

I think the body of the anti-skate device does need to be rotated as Mr Putty indicated. If it is in danger of going "over", then the thread is too short. Even if it doesn't go over, there'll be very low force on the thread. You can look at the pictures in the thread. On my turntable, it all works fine when the lower arm is at the 6 o'clock position, when the stylus is at the start of the LP. This sets a small amount of anti-skate force at the start, and this gradually increases as the tonearm goes across the LP.

And I'd add O-rings or O-rings and brass washers to the lower arm and move it, until the anti-skate works according to the SoundSmith's method. The SoundSmith does also stress that there should be no twist in the tonearm wire. If there's a twist, you may need to add or remove mass on the lower arm. The big advantage of my method is that it has just two adjustments: the amount of mass on the lower arm, and the position of that mass on the lower arm.

It's also true that you can't just listen to one LP, as it may be damaged. Better to play a wide range of LPs and listen for mistracking, sibilance, etc.
Last edited by Golear on Fri Dec 21, 2018 8:59 pm, edited 1 time in total.
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Re: Need help trouble shooting 3D arm

Postby Gshepardbuster » Fri Dec 21, 2018 7:47 pm

I also have a stainless arm along with a 3D arm on my Classic Signature. Now that I think about your issue I had the same. The stainless and 3D arm have a slightly different path along the lift arm pad. I had to slightly adjust the lifting arm when swapping arms to accommodate whichever arm was used. Otherwise about mid record I was getting skips.
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Re: Need help trouble shooting 3D arm

Postby Bill Stevenson » Fri Dec 21, 2018 9:31 pm

In what way did you adjust the lift pad to compensate for the two arms? It is interesting that you experienced it on the Classic, which in my opinion is a hell of a lot better TT than the Prime. But it does seem to be related to the arms rather than the TT itself.
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Re: Need help trouble shooting 3D arm

Postby Gshepardbuster » Sat Dec 22, 2018 6:51 am

To adjust the lift arm you loosen the set screw by the lever with an Allen wrench.
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Re: Need help trouble shooting 3D arm

Postby MMMC » Sat Dec 22, 2018 8:52 am

Golear wrote:
audiom3 wrote:If I rotate the device as others have mentioned, it will pull the A/S device 'over the crown' and it'll fall backwards and thus, disengage. So that just doesn't work.


It's good that you moved the thread so that it is flush with the anti-skate hub, and used one O-ring. There will be minimal change in the angle that the thread makes to the horizontal plane, as the arm moves across the LP. And it precludes the upper arm from complicating things.

I think the body of the anti-skate device does need to be rotated as Mr Putty indicated. If it is in danger of going "over", then the thread is too short. Even if it doesn't go over, there'll be very low force on the thread. You can look at the pictures in the thread. On my turntable, it all works fine when the lower arm is at the 6 o'clock position, when the stylus is at the start of the LP. This sets a small amount of anti-skate force at the start, and this gradually increases as the tonearm goes across the LP.

And I'd add O-rings or O-rings and brass washers to the lower arm and move it, until the anti-skate works according to the SoundSmith's method. The SoundSmith does also stress that there should be no twist in the tonearm wire. If there's a twist, you may need to add or remove mass on the lower arm. The big advantage of my method is that it has just two adjustments: the amount of mass on the lower arm, and the position of that mass on the lower arm.

It's also true that you can't just listen to one LP, as it may be damaged. Better to play a wide range of LPs and listen for mistracking, sibilance, etc.


Gentlemen,

I don't want to play the role of "The Grinch who stole Christmas", considering the time being devoted to setting anti-skating, but I have not seriously concerned myself with other than the Harry old school anti-skating method of the twisted tonearm wire since I read this bit from Harry about what seems like a million years ago and I haven't worried since. I've owned an original Scout, an Aries I with 10 inch JMW, an Extended Aries with a 12 inch JMW, and my current HRX with a 12 inch 3DR.

......"Weisfeld tells this tale: "I was so excited in getting a working prototype of the arm that I forgot to hook up its anti-skate mechanism. And the arm sounded great. So when I noticed what I hadn't done, I hooked up, and the arm sounded worse. I could hardly believe my ears." He speculates that anti-skate devices, with their vibrating metal and twine, just provide another vehicle for the accumulation of unwanted resonances. He also argues that there is a touch of anti-skate, effect, because of the outward tension occasioned by some of the arm's wiring....."

Gentlmen and Ladies YMMV. At the time, approximately 2002, I owned a VPI Scout with only a 9 inch arm, but found it seemed to work very well even though initially thought the wire twist was effective only with the 10 and 12 inch unipivot arms.
I hope this post won't break the site with a flood of posts that will be positive I am advocating ruining their vinyl.

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One of the last HR-X production/ 3DR 12" arm/ ZYX Universe II LOMC with Copper wire/ RCM Sensor 2 phono preamp/ Silver Audio Appasionata IC/ Audio Sensibiity Statement Silver Phono V2 IC
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Re: Need help trouble shooting 3D arm

Postby Golear » Sat Dec 22, 2018 2:14 pm

Peter Ledermann, I believe, encourages use of the mechanical anti-skate. And VPI includes the mechanical anti-skate as original equipment. If you decide to use the mechanical anti-skate, you might want to read my post, as well as others' posts. But you're free to do whatever will work in your system.
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