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-   -   The Ikea curtain rail air parallel tracking tonearm! (http://www.diyaudio.com/forums/analogue-source/76493-ikea-curtain-rail-air-parallel-tracking-tonearm.html)

ericpeters 25th March 2006 05:29 PM

The Ikea curtain rail air parrallel tracking tonearm!
 
The Ikea curtain rail air parrallel tracking tonerarm!

this is basically an idea i have been playing with in my head. I want to make a tonearm similar to the Rockports, Air tangent,Forsell or MG1 and as a base I think i can use an Ikea exatandable curtain rail.
(The Eminent technology has a different style and I think this is not so easy to make)

The curtain rail basically exist of 2 aluminium tubes that slide in eachother the tolerances seem to be pretty good but I dont have a clue is it is anywhere near what would be required for some kind of decent sound.

So I want to cutt off 12"/30cm of innertube and dirl bunch of 1mm holes in it (how many? don't know). Close it at the beginning and end and connect it to a small airpump. I would cut about 4"/10cm of the outer tube and glue a piece of tonearm at one and and counterweigt at the other end.
The wiring and armlift would be similar to what the MG1 arm has. (see MG1 picture for some detail).

Has anyone ever tried this?


ps: a leg of a foto tripod might also be a good source.


The Air tangent
Kuzma Air line
The Rockport
The Forsell

reverber 30th March 2006 09:34 PM

Not sure if the tolerances would be tight enough or not...
Also. drilling the holes wouldn't be very much fun. You would have to drill only from the outside of the tube in (i.e., no shortcut of drilling two holes at once) as the resulting burr would just add to the work of ensuring a smooth and cylindrical barrel. That is the main problem that I see - ensuring that your two tubes remain concentric and cylindrical during all of this process.

I would like to hear how this works though... It just might.


Cody

MosfetOwner 31st March 2006 12:37 PM

While I don’t want to pour cold water on your DIY ideas, I know that quite a lot of electronics were used to control the tracking of the parallel tracking turntables of Revox and the Japanese manufacturers, in order to keep the stylus at a perfect tangent to the record grooves. The reason that they needed the electronics, was that not all records had the same number of ‘tracks per inch’. For instance, many audiophile records have fewer tracks, so that they can have a greater dynamic range. That means that the tonearm tracks faster into the middle than with, for instance, hit compilation albums, where they tried to cram as many hits onto a record side as possible, so that the record buying public thought they would get better value. So most of the parallel tracking arrangements used electronics to make sure that the stylus was exactly in the middle of the grooves, and the tonearm straight, at all times.

The other problem with parallel tracking is making a silent tracking arrangement, otherwise you’ll run into problems of rumble. The top end Pioneer turntable, the PL-L1000, for instance, used a sophisticated arrangement of electro-magnetics in the support and drive motor arrangement so that there was no bearing rumble. According to a review of this turntable in Electronics Today International (Feb 1980), this resulted in a virtually noise-free supporting mechanism, whereas many others that he’d reviewed, using worm drive, belts or rollers, had resulted in “sufficient noise and motor vibration being fed through to the tone arm……to be audible in the electrical output signal”. While an air bearing sounds good, things like noise from the air compressor may be an issue. Indeed, Kuzma state that the compressor should ideally be “outside the listening room”!! (in other words, it’s noisy!)

Personally, I think a standard pivoting tonearm, while it runs into problems like anti-skating issues, is very much easier to design to get excellent sound as a DIY project, compared to most parallel tracking arrangements, which need to be very sophisticated. Still, if you go ahead, good luck – I think you’ll need it! I’d rather buy a top-end Japanese turntable using linear tracking from the 1980s – the very best of them was the Yamaha PX-1, although I doubt there are many in existence, because they cost about $6000 back in the early 1680s, which is probably the equivalent of about $100K these days, after inflation. Most people would have put that sort of money into buying a house! There were also cheaper (but still top-end) models from Technics, Pioneer, Yamaha, JVC and so on. Buy a Jap one, and experiment with that first, is my advice.

EC8010 31st March 2006 01:03 PM

Would that be 1960s, rather than 1860s? I'm fairly sure Yamaha didn't make a linear tracking turntable then...

As for drilling the holes, it's easier than you might think. So long as you use a centre punch to indent the hole properly, there's no reason why you shouldn't drill a photographic tripod or Ikea curtain rail. You'll need to put your power drill in a stand and fit a pin chuck to grip small drills, though. I successfully used 0.32mm drills in a pin chuck in my ancient Black & Decker before I retired it due to worn-out bearings (I cleaned and greased the stand before using it for little drills).

audio-kraut 31st March 2006 01:09 PM

I run the MG1 airbearing arm for over one year now. The compressor - not very noisy to begin with - is in my case behind the attic wall.
It is very easy to construct a styrofoam box to eliminate any noise should you have to place the compressor in the same room as the TT.

I have both a turntable with an sme 3009 and one with the airbearing arm. The tracking on warped records fo instance is quite a bit better than with the sme - which beats the rega rb 300 I had before any time of the day.

The airbearing arm is the preferred playback system in conjunction with a goldring 1042. The other tt and arm are there just for show.

I encourage you to go ahead and try, but look at the design of the MG1.
The holes er very small - about the diametre of a hair? and spaced about 3/4" apart, at 1/4 diameter each around the arm.

MosfetOwner 31st March 2006 01:16 PM

Quote:

Originally posted by EC8010
Would that be 1960s, rather than 1860s? I'm fairly sure Yamaha didn't make a linear tracking turntable then...

Yep, I trained in electronics, not as a typist, and get a bit dyslexic with my typing! 1980s, I meant.

pixpop 31st March 2006 02:02 PM

Quote:

I know that quite a lot of electronics were used to control the tracking of the parallel tracking turntables of Revox and the Japanese manufacturers, in order to keep the stylus at a perfect tangent to the record grooves.
I think you are talking about motor driven linear trackers, that use a motor to move the arm. That's not what happens with an air bearing design.

MosfetOwner 31st March 2006 04:29 PM

Quote:

Originally posted by pixpop

I think you are talking about motor driven linear trackers, that use a motor to move the arm. That's not what happens with an air bearing design.

Yeah, I was. I can't say that I've looked at how the air bearing design works, but surely they need something to make sure that the stylus stays in ther centre of the groove? If they didn't, they'd wear the stylus and record unevenly - probably mainly on one side. Several reviews of the Kuzma Air Line tonearm that I read indicate that it's purely moved across by being pulled by the record, and I'm convinced that would wear a record much more on the outer groove, besides not necessarily producing even outputs in both channels. They criticised it also for being undamped, and stating that on records without the hole being perfectly centred (quite a few, unfortunately), the tonearm kept moving backwards and forwards, often resulting in the cantilever of the cartridge being pulled from one side to the other. Doesn't sound good, to me, considering it weighs a bit more than most tonearms.

I've always wanted to buy a linear tracker, and while the Air Line, and others like it, have some good points, they also seem to have some problems. I'd like to see a stylus that had done about 500 hours on one, and compare it under a microscope with one from a standard pivot type tonearm, with anti-skating set up well, and compare them. Maybe Mr Van den Hul, or Mr Gregory, could tell us? It's just a pity that most of the hi-fi reviewers have swung right away from measurements these days, because a left-right comparison between a cartridge on one of these tonearms may just be able to convince me! No hope of that these days, though, just a lot of flowery, highly subjective language that doesn't mean much from most reviewers!

baggins 31st March 2006 05:16 PM

Hi guys ,

I have a sharp VZ2500 ghetto blaster that plays both sides of an
lp all under digital control .It sounds awful due to worn drive belt and low mass central hub .But I was quite impressed with the drive system and feel sure that it could be adapted to form the heart of a linear tracker Has anyone done this?

You wouldn't need to play the underside of the vinyl. Ha Ha !!

pixpop 31st March 2006 06:48 PM

Quote:

...it's purely moved across by being pulled by the record...
Yes, but that's exactly what happens in a conventional pivoted tonearm. If you watch a conventional arm tracking an eccentric record you'll see it happily moving the counterweight back and forth. Same problem, really.

I don't think an air bearing inherently has greater effective mass, although some specific arms might. For starters, the arm could be shorter, and hence less massive, than a pivoted design.


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