Linn Bedrok LP12 Plinth Upgrade

dover

I’ve never seen any Vertere model, that kind of precision is beyond impressive, it’s downright scary.

The fit of the posts of the SME, Acos Lustre, JVC-Victor tonearms are all similar: snug, mated, properly aligned while making refined adjustments.

My 12.5" long tonearm from Russia, the post is not tightly fit, goes into it’s base plate very easily, like the Linn arm does in that video. They think it’s ok if it’s held in place by a set screw. I had them modify the base for 2 set screws (enhanced inconvenience, eh), and I added a layer of very thin tape around the post, a much finer fit, stays aligned while adjusting it’s height (with it’s built-in micrometer which is a nice feature).

@elliottbnewcombjr 

Just an after thought.

Logic had Syrinx manufacture their mounted tonearms originally but later developed their own Datum II and the highly regarded Datum IIS. I have known people who have bought a turntable just to lay their hands on a rare Datum IIS

mylogic

I found the Datum II and IIs silver wire version, it appears they changed the mount from a threaded post and nut below deck to a Jelco Type surface mounted 3 screw base plate, am I correct about that? I prefer removable headshells. They do not mention it, but I think I read that the Datum II and IIS includes azimuth adjustment at the end of the arm, I see what look like 2 screws

I just mounted my new to me Vintage JVC Victor UA-7082 11-1/8" long arm. It's counterweight section's rubber isolation sag was properly repaired. The anti-skate adjustment is the smoothest I ever encountered, like the Acos Lustre GST-801 it is easy to adjust while playing/listening, although I prefer setting it while lowered onto the smooth side of my alignment disc

. After releasing the JVC height locking ring, then you can place the stylus and adjust the height while playing, however final locking is a two handed job, not while playing.

My Acos Lustre GST-801 which I learned about here is my favorite arm, easy to release/adjust/lock everything while playing: height/tracking force/anti-skate. I use an AT headshell with azimuth adjustment. I wish they made a long version of it.

I just noticed, the Logic Datum II looks to have a very compact/short length counter-weight section, it might fit on the left side where my Mission/Jelco 774 is, I will need the measurement from pivot to the rear end, and I need to double check the overall height for clearance when the dust cover is on

This still shows the 12.5" blackbird arm, I removed it, spun the armboard around 180 degrees, and used the original hole that the 45 adapter is show in, where the original 7082 arm was.

Alignment LP, one side smooth for observing/setting anti-skate

@elliottbnewcombjr

Datum II & IIs

The Datum I was manufactured by Syrinx and up to that point had threaded posts and nuts to mount.

Logic aquired Syrinx and made in house the Datum II & IIs with the three point mounting collar. They mounted both Datum’s on their DM101 and Logic Tempo turntables.

Mounting hole 30.5mm

Effective length 228mm

Pivot to spindle 210.7mm

Overhang 17.3mm

Azimuth is adjustable by two bolts.

You are correct the counter balance is very up close to the pivot due to the tungston counter weight.

All of the Syrinx arms…LE1, up to the Datum I had the same measurements and these were carried over to the Logic produced Datum II & IIs

One thing to note is that when Logic folded the companies stock was bought by Manticore Systems Engineering. Their well liked Mantra turntable was a leading model in the UK. The later Datum IIs arms were modified to their new specs under the MSE logo which appears on the arm pivot. Superior bearings and improved external finishing also cured the anodising effect of UV in earlier models.

A Datum IIs with the silver wire was considered better than the Linn Ittok LV3 Mk2 and considerably less expensive. The Datum I, Syrinx PU2 and PU3 models were claimed by some to be ‘’Ittok Killers’’ within their individual timeframes.

Search the ‘’Vinyl Engine’’ archives further to confirm this information if you wish. l own a few Syrinx arms so l am sure l have given you the correct info.