Magnepan Unitrac tonearm balancing

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Samcoffeeman
United States of America
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Joined: 04 Jun 2019 16:18

Magnepan Unitrac tonearm balancing

Post by Samcoffeeman » 16 Jun 2019 01:34

Hey,
I'm a novice, just upgraded I bought a second hand Rega Planar 3 with this tonearm and I can't get it to balance. I may be a bit out of my league since this is the first time I'm trying to balance a tonearm. I've got the weight all the way back and the scale reads 4.5 grams. Haven't even come close to it floating. Anyone have experience with this arm? I don't have a manual or anything so I'm just going off of what little there is out there on the net. I do have a digital needle scale and some BBs to use for the counterweight. It's got a Denon 103R with cocobolo cover. Previous owner swears it balanced and worked well.

JaS
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Re: Magnepan Unitrac tonearm balancing

Post by JaS » 16 Jun 2019 12:07

How heavy is the cartridge? According to the manual an auxiliary weight may be required 'for cartridges weighing 8g or more'.

https://www.vinylengine.com/library/mag ... ac-1.shtml

Regards,
JaS

Samcoffeeman
United States of America
Posts: 3
Joined: 04 Jun 2019 16:18

Re: Magnepan Unitrac tonearm balancing

Post by Samcoffeeman » 16 Jun 2019 22:52

Thanks, for some reason I haven't been able to download any of the documents. Maybe it doesn't work on mobile, I'll have time tomorrow to try on my PC.

nat
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Re: Magnepan Unitrac tonearm balancing

Post by nat » 17 Jun 2019 00:25

That is a great arm. Don't do anything rash with it. You should be able to get it balanced with no problem, but the chance of any problem being caused by mechanical issues is vastly lower than the chances of the problem being unfamiliarity with the arm. So get the manual, which is in the library because I have consulted it, before doing anything more.
I say this because the first response of quite a few people to any confusion about how to set up an arm is to start taking it apart, rather than to find out what the intended method is. Putting a tightly toleranced arm back together correctly is a lot more difficult than the disassembly is.

pivot
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Re: Magnepan Unitrac tonearm balancing

Post by pivot » 17 Jun 2019 01:53

Sold 'em back when they were new - you NEED the manual.

You also need to check that the mounting has been done correctly. Seen more than one that were just dropped into an existing mounting hole on a turntable. The base and pivot are in a unique relationship and the geometry does not match any other arm. The base will fit into a 7/8" hole made for another arm but will not be able to be adjusted to correct offset/null points. (Interesting it may fit into an SME cutout if used with the supplied washers)

Do you have ALL the weights? You need the vertical alignment weights to set azimuth.

Do you have the anti-skate cup assembly and the shot to load the cup?

Do you have the VTA adjustment wrench? If you are very careful you can use the wrench to do "on-the-fly" VTA adjustments.

There is a list of parts/tools in the manual.

Designed around the no longer available Denon 103D. The "D" was a high compliance variant for the 103. The Unitrac is a low effective mass (8 grams) arm......NOT suitable for the current 103 or 103r.

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