diy tangential tonearms


I hope to have a tangential tracking tonearm one day. The available new ones cost five figures and Revox is not acceptable because of the difficulty in maintaining it and others come with turntables which threaten to be difficult to repair or rebuild. I like the turntable I have and a tangential tonearm could be installed through what appear to be three standard positioned screws which hold the present arcing tonearm in place.
The expensive tangential tonearms have air bearings which minimize any rumble from the arm sliding down its track. Other such tonearms use a servo to try to move the tonearm which can't be precise enough to do any good when the spacing between record groves varies with the amplitude of the music signal. Furthermore, air bearings will introduce the hissing sound of the air and that hissing noise is bound to be louder than any speaker noise the friction of an oil bearing might introduce. Air pumps, the dirt and filter and water condensation problems are not acceptable. From what I can find, my only way to have a tangential tonearm is to make one myself.
Does anybody have any suggestions, for instance, a set of plans I could buy for a tangential tonearm which does not require an air bearing or a servo motor drive? I have built other electronics myself which I like more than what I could buy if I could afford it. I think if I took my time machining the parts it would make a nice finishing touch to my turntable. Your ideas would be of great value to me.
128x128drbarney1
Thanks for coming to the forum and sharing your thoughts Andy.
I still have yet to decide on trying one but your comments here may well help.
See if you can spot where things go wrong:
With the pivoted tonearm a typical tracking error causes one side of the needle to delay on the order of about 0.25 milliseconds which at the speed of sound of 1000 feet per second (the acoustic speed outdoors on a cold winter day) this is equivalent to one speaker being 3 inches further away than the other But with two ears is this significant, 

Got it? No? Could it maybe be....
tracking error causes one side of the needle to delay on the order of about 0.25 milliseconds 
Delay .25ms compared to.... what? I don't think its the other side. The needle does not delay at all. It keeps right on moving the whole time.



Air bearings have their own problems. The biggest one is the pump after that is the noise. Air makes high frequency noise as it passes through pores and passage ways. It is impossible to get rid of it all.

Low pressure aquarium pumps used for the AirProdigy and Terminator air bearing tonearms do make a noise, it's true, but the brand of pump I use for the AirProdigy isn't too bad at all. It's best placed in another room connected by 10m of tubing (which obviates the need for an expansion bottle) but you can use it in the same room if it's insulated well. High pressure bumps used on arms with cylinder bearings are another matter though. Much noisier!

As for noise from the air coming through the tiny holes in the airtrack of low-pressure arms, well, it's pretty much non-existent. You have to put your ear right up to the airtrack of the AirProdigy arm in a completely silent room to be able to hear any noise at all. Once again, that's not the case for high pressure arms!