Linear tracking turntables

The fellow who does my Quad conversions was mentioning that he strongly believes in linear tracking turntables. He swears that the inner groove distortion is eliminated and that a linear is the only way to really transcribe a record correcty.

What say you folks?

 

What makes the cutter arm different than the playback linear tracking arms? Are we looking at different functions generating different designs?

 

Steve,
What linear trackers have you heard?

 

The concept SEEMs to be right on....playing the disc back the same way it was cut.


But I dont think Ive ever heard one, ever. I never owned one, thats for sure

 

http://www.airtangent.net/fplaybacklinear.html -

The entire arm must be moved along a track tangent to the record-a difficult engineering challenge. The problems associated with many linear-tracking arms usually result in greater tracking errors than you'll find in a properly set-up pivoted arm. Any linear arm that permits yaw - which can be caused by a variety of mechanical conditions - will describe, instead of the desired radius, a series of differing arcs across the record surface.

 

Think of it this way--the cutting stylus is in an "arm" (so to speak) that is driven by a motor across the surface of the lacquer master; the motor is creating the linear motion. In a turntable, the groove spiraling toward the center is what is pulling the arm across the record; in this case, the record is directing the motion, for the most part.

In cheaper linear tracking 'tables, sensors in the arm would trigger motors that assist the arm in moving the stylus across the record; if not, there would be too much pressure on one side of the stylus, pulling the arm along the linear axis, which would increase groove wear and distortion. The really expensive linear tracking arms actually ride on an air bearing; since resistance is extremely low, the linear assembly just skates along the air cushion as the stylus pulls it across the record.

In theory, the linear tracking system holds the cartridge at an exact, correct angle throughout playback, where a pivoted arm is correctly aligned at only two points in its arc. Thing is, the forces of the groove that need to move that linear assembly across the surface of the record may counteract some of the advantages of the perfect alignment.

The only linear tracking 'table I've ever heard is the one Revox used to make in the 80s, and I only heard it in passing (didn't audition it, IOW). It looked so darn cool, though...

 

I always liked the concept of a linear tracking TT, but I always felt that there were always likely to be problems: the more complicated a machine is the more likely it is to require repairs and adjustments.

I have heard one that I thought was very good though, a Beogram 4002 made by Bang and Olufsen. One of my friends has owned his since it was new, and it has served him well. Unfortunately, B&O no longer makes phono cartridges, nor do they offer stylus replacement (the B&O carts for this TT don't have user replaceable styli) so he has a very beautiful museum piece. Here is a link for one you could buy on eBay:



http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14980&item=5714804758&rd=1

Beautiful, isn't it? BTW, when these were offered for sale new the prices ranged around $1000.00 IIRC!

 

I heard the Kuzma Airline linear tracking arm... amazing what it does, if it weren't 8k i'd buy it today!

 

Fascinating. The site you link makes it sound like the way a hard drive's read/write heads work. If only IBM made turntables.

 

I have an old linear turntable that I used to use as a second player for LPs and 45s, but I just didn't feel like it tracked all that great. I then bought a P-Mount Stanton cartridge with a 78 stylus, wired the turntable to play 78s, and it's my dedicated player for that format - I love it, and it seems to perform much better, although it's comparing apples to oranges in some ways.

 

A hard drives read write head is on a pivoting arm.

 

Rudy, Darn good explanation.

I have heard the system below at a demo at HE2001, it is one incredible TT, however, it is a $10,000+ setup. The Clearaudio Reference table with the Souther linear tracking arm.

 

Personally I find that my Eminent Tech air bearing linear arm far outperforms the previous Rega Origin Live modified arm on my VPI turntable. When I switched to the ET any end-of-side distortion caused by tangency disappeared, though on some longer LPs I can still hear a bit of "pinching" caused by the way the cutting is adjusted toward the end of the side. Air bearings are a pain in terms of aor supply and wire leads, but the results are worth the effort. Stay away from servo arms that need the arm head to significantly deflect before they move.

John K.

 

I briefly had a HK Rabco ST-7 turntable back around 1977. It had a lot of promise, but unfortunatley was made pretty cheaply. IIRC it had an Ortofon cartridge which you were pretty much stuck with. I seem to remember that it also had a problem with feedback in my system. I didn't keep it very long. I considered it quite a downgrade from the Thorens table I was using previously. Nice idea, but poor implementation. Soon after trying this I got my Technics SP-10 and I haven't looked back since.

The Garrard Zero 100 was an interesting approach to the tracking angle dilemma.

Has anybody tried one of the new laser based turntables which have been out for a while?

 

That was the turntable and arm that I had before I changed to my current set-up and it sounded wonderful IMO. I have heard some mighty fine linear tracking replay systems but they have tended to be quite pricey.

Andrew

 

Hello to all.

I am "currently" building a DIY Teres turntable that will have a linear tracking tonearm.

What is unique about it is that it will use a standard tonearm but the tonearm platform will move as the record plays. Also, it will move the arm at a steady speed along the record, not waiting for an error to appear to catch up. But it will detect errors and do a position and speed correction. Sounds complicated but it is incredible what you can do now with cheap motion controllers.

Linears, IF PROPERLY SET UP, avoid angular errors between the groove and the stylus and also bypass skating issues. Conceptually they are right on the mark but the advantages in the real world are probably moot.

 

Hell, IBM doesn't even make hard drives anymore, sold it out to Hitachi.

 

I owned a linear tracking turntable for over 20 years, the Phase Linear 8000 made by Pioneer in 1981. I just got rid of it about 2 months ago. It worked flawlessly and sounded nice. It was elaborate with a laser beam controlled servo-mechanism. The laser determined the exact size of the groove and fed the information to a chip that in-turn sent an electrical signal to the servo-motor that controlled the speed the tonearm moved. It was elaborate but in 23 years of use it never failed. The new owner seems to be happy with it as well.

 

One of the few, perhaps the single one, linears with a real tonearm.

The Phase Linear seems to be a great candidate for cannibalizing the parts and do a DIY.

 

Didn't B&O's linear tracking 'table have a similar setup? Theirs had a second arm that hovered over the grooves just ahead of the "playing" tonearm.

 

Almost bought a Mitsubishi LT5V about 10 years ago. A linear. You load the record like hanging a picture. Glad I got talked out of that deal! Linear isn't always good....

 

That's correct, Rudy, it was a very elegant and elaborate design. BTW, my friend's records sound pristine to this day, so the B&O system worked very well indeed.

 

I almost bought the B&O's linear tracking table. Can't remember the model number off hand. I went with the RX-2 instead. It was more in my price range at the time.

 

Done right (eg. Goldmund, Rockport) the results can be stunning.

However most mainstream attempts were no better, sometimes even worse than a good pivoted arm setup.

As usual it's the implementation rather than the specific technology that counts.