Magnepan tonearm


Hi,

I posted some time ago about an old Micro Seiki turntable (BL21) that I purchased w/ a Magnepan Unitrac tonearm. I just purchased another turntable, a Systemdek 2X2 (similar to the current Audio Note 1 table), and moved the Magnepan to the Systemdek. Even with a budget Grado, this combination is quite impressive, and an improvement from what I thought was quite decent sound with the Micro Seiki. Very coherent, with a nice midrange. Perhaps not the best LF, but only compared w/ much more expensive vinyl rigs. The Systemdek came w/ a Rega armboard, which fit the Magnepan. However, I understand that the ideal mounting distance for the Magnepan is slightly off with the Rega armboard. I asked this question once before here or at AA, but does anyone know what adjustments I should make to the armboard to get the Magnepan in an ideal setup? Thanks,

TLH
tlh28
Here is the relevant information.

http://db.audioasylum.com/cgi/m.mpl?forum=vinyl&n=586421&highlight=magnepan&session=

Also, read the complete thread.
Hope this helps.
Jeff
I have the Magnepan arm which I have not yet mounted/used. I got it as a "throw-in" on a TT I bought last year. So, I'm not at all an expert but here's what I have found out:

The mounting distance is 224.1 mm vs 222 for the Rega. There's a mounting template available to get it set up right though.

The Magnepan mounting template, manual and a brochure are available on Vinyl Engine. Here's the URL for them: http://www.vinylengine.com/library_model.php?make=Magnepan&selected_model=Unitrac%201

There's a fair amount of discussion of this arm on Vinyl Asylum - search on "Unitrac". At least one of the inmates is somewhat of a guru on the arm.
Bdgregory,

The mounting distance is not 224mm. That is the pivot to spindle distance....the pivot and mounting hole are different distances from the spindle. Look at where the actual pivot is and you'll see that it's not over the mounting hole.

The spindle to mounting hole is ~220mm.
This post and the others regarding the Unitrac show that is has a loyal following. Too bad Magnepan doesn't bring it back into production.
The mounting distance is not 224mm. That is the pivot to spindle distance....the pivot and mounting hole are different distances from the spindle. Look at where the actual pivot is and you'll see that it's not over the mounting hole.

The spindle to mounting hole is ~220mm.

. . . thanks Jeff. I was just quoting the measurement from Vinyl Engine's tonearm db, and assumed it was right. I haven't had a chance to look closely at the arm geometry.

either way, the net is it's 2mm different than the Rega. Is that correct? Is that significant enough to be concerned about using a Rega armboard? Based on TLH's comments, it seems the standard Rega mount at least work satisfactorily. (I'm interested in this because I already have a Rega armboard - and it will be easier to try mine if I don't have to build a new armboard for it initially)
Thanks to all. The arm sounds really good on the Systemdek, even with an inexpensive cartridge, but I my ears tell me its not quite set up ideally. I'm upgrading to a little better cartridge and will play around with setup some more once I get the new cartridge. I was hoping that the armboard had a little play so I could adjust the distance if needed, but the arm fits pretty snugly on the armboard. I would have to cut into the armboard hole a little to make adjustments. Anyone think it would be worthwhile for 2mm? Thanks,

TLH
Could you not make up the two MM with the cartridge location?
TLH,
If you want it perfect, you might have to drill a new armboard. There's another set-up parameter with the mounting hole. From center hole to spindle and to the straight ahead position, the hole should be located so this is a 57° angle.
I was thinking of making a headshell lifter like an outrigger that's the same on both sides, but I haven't gotten around to it. A conventional lifter works, but it throws off the balance slightly.
Regards,