Linear Tracking

Lazarus Short

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#62
Finally back to this thread - Laz has, as his only TT, a Sony non-Biotracer linear tracker. It's packed for shipping, so I'm not certain of the model number. I'm more concerned with cartridge/stylus/phono preamp than with the turntable itself. I'm currently working on a deal for a Shure P-mount to house my NOS N92E stylus.
 

laatsch55

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#65
read the 2 page thread, very interesting stuff. even with something essentially easy to prove with physics and trigonometry he still got a lot of flack, amazing...
 

Elite-ist

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#66
Here is a bump for an old thread about linear tracking turntables - pros & cons.

Nando.
 

Gepetto

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#67
Good stuff...

Linear tracking ideally is the way to go since that is the way the master was cut.

The problems over the years has always been the ability to properly servo over the record groove without imposing additional side load on the stylus which defeats some of the advantages of linear tracking. Or if the servo worked properly, to make the servo mechanism reliable enough so that it did not break in time. Most of the mechanisms are complicated and pretty fragile with a tendency not to fare well over the long haul. I remember Rabco had a very high end capacitive tracking servo arm but it did not do well in the reliability or cost arena.
 

Elite-ist

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#68
Even though this thread has gathered a few cob webs, I'm sure most respondents, thus far, are well-rooted in their opinions. But if there's someone, new to the forum who hasn't lucked upon this thread, it might be an incentive to contribute.

Nando.
 

Rat44

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#69
Linear trackers always sound good WHEN they are working properly.
And thats the catch.
A complicated system that is not always reliable.
I had a Rabco ST 7 that was my dedicated quad table and it sounded great.
 

Elite-ist

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#70
Interesting, Dennis. Probably, it doesn't help for me to coddle my LT by not using it. Something is bound to malfunction from lack of use. Which quad cartridge were you using on it?

Nando.
 

Gepetto

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#71
Linear trackers always sound good WHEN they are working properly.
And thats the catch.
A complicated system that is not always reliable.
I had a Rabco ST 7 that was my dedicated quad table and it sounded great.
The Rabco SL-8e was one I saw when it first debuted. It was a thing of beauty to an audio nut. It was unbelievably complicated however and priced 'not to sell'. Too bad no one to date has really mastered making them reliable and affordable. In this day of laser everything/everywhere, it could probably be done more cost effectively and reliably than back then.
 

Northwinds

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#72
Sharp made a pretty decent linear tracker back in the 80s, the RP-117. My friend Jack told me he just pulled a BSR 4000 Accutrac out of his attic for use. Man, I still remember when he got it. An acquaintance had access to some pretty sick audio gear, all new in box. Dude even had a system sitting on the doghouse of the van with huge Sansui speakers in the back LOL. We both bought shit from him and then later we found out he was in a gang of dudes that robbed parked traincars!!!!!!!
 

Rat44

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#73
Interesting, Dennis. Probably, it doesn't help for me to coddle my LT by not using it. Something is bound to malfunction from lack of use. Which quad cartridge were you using on it?

Nando.
I was using an AT 15-Sa which I still have.
Wish I had kept the table knowing what I know now.
 

Lazarus Short

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#75
Good stuff...

Linear tracking ideally is the way to go since that is the way the master was cut.

The problems over the years has always been the ability to properly servo over the record groove without imposing additional side load on the stylus which defeats some of the advantages of linear tracking. Or if the servo worked properly, to make the servo mechanism reliable enough so that it did not break in time. Most of the mechanisms are complicated and pretty fragile with a tendency not to fare well over the long haul. I remember Rabco had a very high end capacitive tracking servo arm but it did not do well in the reliability or cost arena.
The trick about LTTT's (if I can coin an acronym) is that they are either cheap plastic, finicky, or expen$ive. I've had them all:

cheap plastic - some cheap thing I don't remember the brand of - had to get the arm working, and with that done, I found that the platter bearing was overly noisy - got rid of it

finicky - an H/K with a factory Rabco arm - ST5? - it needed too much attention but worked well when it worked - sold it

expen$ive - B&O 4004, and it was a thing of beauty but not a joy forever, for I foolishly swapped it

My Sonys have not been cheaply made (though some would say so), they are not finicky, and they are not expen$ive. I put on the LP, press one button, the LTTT cues itself, plays the LP, returns to rest, and turns itself off, just like Arlo Guthrie's motorcycle.
 

Rat44

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#76
Have you had much experience with the Technic's ?
Seen many of them when I was in the service.
Used to refer to them as the 'Close and Play" tables .
 

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#77
I have an H/K with a Rabco 7 I believe. Haven't even plugged it in. Got 4 other tables I got at a " druggie got locked up" sale...
 

Elite-ist

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#78
Lee: You put yours in service and I might do the same with mine.

Nando.
 

MarkWComer

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#80
I'm still in love with my Pioneer PL-L1000 (sold as the Phase Linear 8000 Series II in the USA). I don't know what I'm gonna do when something goes dead on the tracking system- and I know that eventually it will. It's amazing the prices they fetch when they show up on ebay, sometimes over $1000. As far a consumer turntables go, this was probably the most affordable and reliable LTTT you could get. I bought mine on ebay from a guy in Washington state for $92, listed as malfunctioning, and no one bid against me. The arm lift belt was stretched out of shape (achilles heel of this unit), one of the rails that the arm carriage rode on was loose, and the rear bearing roller was loose as well. Easy to fix mechanically, but things like arm return speed, end-of-record return trip, and stylus point setdown for play all require an oscilloscope to adjust.

I also had one of the Harman/Kardon LTTTs, the ST-8, and that sucker was the most finicky things I've ever screwed with. I liked the mechanical design- which seemed to be more dependable than using optically coupled sensors for tracking correction- but once I had the roller adjusted correctly on the H/K it would work for about a week, and then I would see that the carriage would either lead or lag the cart by a few degrees. The sucker just would not stay in adjustment for very long.

The H/K / Rabco series used a rotating cylinder at the bottom of the tonearm carriage, the cylinder was coupled to the turntable with a belt. A "tire" at the bottom of the tonearm carriage tracked the rotating cylinder and played a game of "catch-up" with the stylus point. All well and good given the pitch of the spiral of the groove on the recorded areas, but for those records that weren't recorded to within 3/4" of the eccentric groove, the mechanism couldn't catch up fast enough, pulling the stylus out of the lead-out, and you ended up hearing the matrix numbers in the deadwax being played through your speakers. Mechanically, it was good in theory, but in practice, way too finicky for the end user to continually adjust.

The platter being coupled to the tracking cylinder (in my experience) also lead to speed inaccuracy. You adjust the speed, see that the strobe markings are stationary, and a few minutes later the speed drifted.

The H/K tonearm was a travesty as well, the "headshell" was in fact the bulk of the tonearm, which prevented the user from quickly swapping out a cart. The screw holes were round so that when you mounted a cart you couldn't adjust overhang to zero with any precision (actually the only cart alignment necessary for LTTTs, other than VTA). This wouldn't be an issue if the cart manufacturers kept the centers of the mounting holes and the stylus tip at the same distance- but- they don't!

Edison's original was probably the best idea: a fixed groove pitch and a screw-driven tonearm!

So these are the only two LTTT designs I've used. Those air-bearing jobs by ClearAudio cost as much as a Harley Fat Boy. Perhaps one day I'll run across a Pioneer PL-L1 at a Goodwill store...
 
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