Linear-tracking Turntables!

[mep]

I remember my first surge tank I built for my ET-2 arm. I followed the advice from a TAS article and built one from a 5 gallon jerry can. The inlet and outlet tubes gave me the damndest times because the pressure in the tank was always looking for a place to escape and it would always pop the epoxy that was holding the outlet tube to the tank.

 

[MylesBAstor]

As the bearing of a linear tracking tonearm must be perfectly parallel to the platter and the orthogonal arm must always be in a tangential position, mounting and setting a linear tonearm is more critical that a pivot. If you make a small position error with pivot arm you will not get the maximum of the system - if you do the same with a linear tracking arm it will start skipping grooves.

But you you get a turntable system such as the Forsell or the Bergmann, that comes with an integral mounted air bearing, you will skip all the troublesome phases, and will find that the setup of a linear arm is much easier, more exact and faster than that of a pivot tonearm.

As someone already said it you have an air bearing tonearm the pressure meter (that costs less than usd 5) is really mandatory. You do not need a precision one, but you will feel much better knowing there is enough pressure on the system - and it is also an useful indicator that you forgot to switch off the pump after the listening session.


.

No what's mandatory is an inline water filter to take out condensation in the air line

Israel Bloom used to sell a surge tank/air flow meter combo at one time.

You know the funny thing? I had a renowned reviewer tell me that there was no way a surge tank/air pump/etc. could make a difference with the ET arm And w/o listening. Wonder what he thinks now ?

 

[MylesBAstor]

I remember my first surge tank I built for my ET-2 arm. I followed the advice from a TAS article and built one from a 5 gallon jerry can. The inlet and outlet tubes gave me the damndest times because the pressure in the tank was always looking for a place to escape and it would always pop the epoxy that was holding the outlet tube to the tank.

That might have been my piece If not, did it for Sounds Like.... Too long ago to remember

 

[mep]

Could have been Myles. My surge tank I have now is much the better. It is made out of PVC pipe, has no leaks, and it has a pressure gage mounted on top of it.

I will never forget the first time I dropped the needle after I finished the first surge tank. The increase in bass was incredible and the sound overall was smoother. That would have been around 1987.

 

[Johnny Vinyl]

John, This is perhaps the answer to everyone's question: http://www.stereophile.com/audaciousaudio/hifiction_thales_av_tonearm/index.html

Maybe the best of both worlds

Thanks Davey!I think I may understand it now.

 

[microstrip]

That might have been my piece If not, did it for Sounds Like.... Too long ago to remember

Myles,
You were even more guilty than you remember: you wrote the review on the Motronix Acuflow Air Regulator, and as I could not get it in my country I had a lot of trouble sourcing all the parts and assembling it myself. Do not deny:

Form TAS issue 87

 

[MylesBAstor]

Myles,
You were even more guilty than you remember: you wrote the review on the Motronix Acuflow Air Regulator, and as I could not get it in my country I had a lot of trouble sourcing all the parts and assembling it myself. Do not deny:

Form TAS issue 87

Jeez...my copy is long in storage. Can't believe you could actually find it Thanks for sharing the memory !

 

[Johnny Vinyl]

Micro_ That is so cool! Wow!

 

[beek]

Ok. Forgive my ignorance, but can't a Linear Tracker be made without an air-supply? I forget now who it was, but someone bought a Mitsu linear and I didn't see any air supply.

Reminds me of the Rabco I had in the 70'S that must suck by todays standards..

 

[mep]

The Rabco sucked by the standards of the day when it was introduced.

 

[beek]

The Rabco sucked by the standards of the day when it was introduced.

I was young what else was available at that time?

 

[jadis]

To me, sometimes it's good to do something difficult at an early stage. In 1987, after playing with the common table with pivoted arm, I decided to go the way of the air-bearing linear tracking ET-2. I chose a sturdy VPI HW19MKII to set it on, and after time consuming initial set-up, little would I have thought that I was going to use the combo till now, some 25 years after. The performance was good for me that I kept thinking throughout these 2 decades that to 'improve' on its sound, I should be spending 3x more for the tonearm and 10x more for a TT, that is if I want to go 'all-out', so to speak. Kids growing up and 2 college tuition fees hosed me down. And the thing is, I've been quite happy with what it's been doing and barring a direct A/B with a Phantom/HRX combination, I really don't know what more I'll be having or what I have been missing. Re the air pump, there are many ways to skin that cat. When I started with an aquarium pump, I fabricated a steel cage with fiberglass inside to virtually seal the pump inside the latch. Result was very satisfactory. Later on, I got an original Et2 pump and that is very quiet, I can hardly hear it a meter away from it. The only thing left to do is to clean the air bearing with alcohol on cotton buds maybe once every 2 months. I have used 3 very small air filters (from Bruce T) in the course of its run, and that's it. It's been a work horse for me all these years and I like it.

 

[mep]

I was young what else was available at that time?

SME arms for one.

 

[mep]

I have always been fortunate that when I owned the ET-2 (and I still do), I always had another adjacent room to install the pumps and surge tank in. I always drilled a hole through the wall and ran my air pressure tubing to the ET-2. I have a hole in my room downstairs right now!

 

[beek]

SME arms for one.

I meant in straight line arms.

 

[mep]

Sorry Bill, I thought you meant what else was out there that sounded better than the Rabco. I don't claim to know the history of linear tracking arms, but I'm not sure there was another commerically available linear tracking arm when the Rabco was introduced.

 

[mep]

Some people trust, others verify.

Ok Ronald.

Like many things, linear trackers have advantages and disadvantages. I like to know what I am getting for my money.

Doesn’t everyone?

Almost no latereral tracking and skating error. I playback the same way the master was cut. Rumble is more than 60db down so its darn hard to hear and it is IMO a damn good looking deck. Sound, well thats the cartridge and cartridge loading job, you can make it sound any way you want given cartridges are serious tone controls.

Sort of true and sort of not. The table and arm has a huge influence on the total sound. So does the cartridge obviously, but it doesn’t stand alone in the deal.

As for quality of LPs, the deck can distinguish everything test records can throw at it vs what actual real LPs limits are.

And pray tell, what LP limits does your old Yamaha tell you about?

Big brothers the Yamaha PX-1 and 2 have better signal to noise (3db) but wow and flutter about the same. Those are nice decks and command premium prices but use the same motor and control circuits but are mechanically a bit better.

A 3 dB reduction in noise is a pretty big deal. It’s makes you wish you would have bought the big brother.

I lift the hinged cover with my pinkie, put down the record and clamp, press 30 disc size button, lower the cover and enjoy. Sweet. Tom

I have no idea what “press 30 disc size button” means.

 

[beek]

No Problem, wish I still owned everthing I had since 14 yrs old..............

 

[RBFC]

As I've mentioned here before, I owned an ET2 tonearm which Bruce Thigpen had helped me modify. It had a tighter tolerance air manifold (in which the arm tube slid) that would not even function at the standard pressure produced by the stock "aquarium" pump. I used an oil-less air compressor located in my basement, coupled with an in-line pressure regulator and oil/moisture filter. The 20 gallon tank on the compressor, when running the arm at 40 psi, would last about 25-27 minutes (perfect for one album side, then took 2 minutes to refill). It provided absolutely pulse-free air flow, since the compressor was not running while the air bled out to feed the ET arm. The boost in pressure improved the bass performance of the arm without a doubt. While it took a bit of effort to get it all set up, it was plug & play when listening to music once I had it dialed in. The occasional cleaning of the arm tube and manifold was all that was needed. I have no reference comparisons to the good pivoted arms of the day, so I merely state that the TT sounded extremely good to me and many others who visited. All this taken into account, the effort and logistics of the air arms seems to offer quite a high price to the user today, compared to the quality of pivoted arms that others speak so highly of.

Lee

 

[microstrip]

I was young what else was available at that time?

The 1985 TAS cream of the crop included the Syrinx PU3 , the Alphason HR100s, the ODissey RP1-XG, the Sumiko MDC800, the Eminent Technology, the Fidelity Research FR64, the Zeta, the Sumiko MMT and the Triplanar. I have owned two thirds of the members of this list in the past and still own one third of it ...