diy tangential tonearms
For this price, it might be worth dealing with the air, no? Terminator? $1200? https://www.musicfromvinyl.shop/#home More info: https://www.trans-fi.com/terminatortonearm.htm |
drbarney1, the air bearing is to reduce friction to a minimum not reduce rumble. The rate of travel is so slow that the frequency of any noise associated with the movement would be less than 1 Hz. 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. I personally prefer any of the great 12" pivoted arms but if you absolutely have to have a flat liner take a good look at the Clearaudio TT-5 It is relatively inexpensive and works great with any medium compliance cartridge. |
Damn @uberwaltz, I just looked at your link. The Air Prodigy appears to be a note-perfect Terminator knock-off. 500 bucks? How can you loose?! If the Terminator is a great bargain (I think so), the AP may be twice the bargain. I’m a little leery of the nylon arm wand, but that may turn out to be unfounded. If I didn't already own a single-run silver-wired Terminator, I'd be all over the Air Prodigy. |
I know Eric, near perfect" copy" . Yes the nylon 3d printed tonearm may be unusual but it's probably less likely to have an effect on this application than a regular pivoted system. I do like the fact it is supposed to run on just a low pressure air pump. I'm close to biting the bullet, shoot it's less than the cost of one PPT Omega plus mat for heaven's sake. I have wasted way more that that in the past. |
@drbarney1 Assuming your labor is free, what is your budget for materials and parts ? fwiw I know of two people that went this route. They both had the same challenge The Bearing "House" aka the Bearing Chamber. They both ended up with the same type of solution. They took the (the bearing house) from an existing design and they went DIY for the everything in front and after the bearing house/chamber. If it doesn't violate patents, and copies are not made for others - then I guess you can call it DIY. Someone correct me if I am wrong. |
I have not made any hasty decisions on this, but here is what I conclude so far: I am not interested in air bearings because they are too complicated and too given to maintenance requirements and the noise they make diminishes the signal to noise ratio as a whole of the system - such noise would not be tolerated if it cane from the speakers. If I went the tangential tonearm way I would get a used turntable with a servo driven tonearm. The tracking error is reported to only go up to at most 2 degrees before the servo applies correction, verses 15 to 10 degrees for a pivoted tonearm. 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, It does not seem to deter engineers who specialize in their subject more than the general physics you get from a PhD program from using 9 inch tonearms instead of 12 inch tonearms to tame resonant modes in a tonearm. Still, there is something almost Zen about a linear tracking tonearm which I find philosophically attractive the way I find something akin to a Viking Valhalla to the degree of Wagnerian about using radio station transmitter tubes in a stereo amplifier. I look forward to the comments of others on this matter. |
drbarney1 The tracking error is reported to only go up to at most 2 degrees before the servo applies correction, verses 15 to 10 degrees for a pivoted tonearm.Hmmm, I’m not aware of any pivoted arm that would have tracking error that high, except perhaps one of the "zero offset" arms. The maximum tracking error of a typical properly installed pivoted arm is on the order of plus-or-minus just a few degrees. By way of example, the SME V is spec'd with a maximum tracking error of 0.012 degrees per mm from null. |
drbarney1 ^^^^^^ 1) Complicated - As this is an audio hobby - complicated is but relative to the individual. 2) Maintenance - As long as the air is dry there is no more maintenance than any pivot arm. Do some research on Timeter Aridyne. 3) Noise - I will assume your statement is based on assumptions or theory; or you have heard past setups which were not set up properly and or just a plain bad design. The simple test is to ..... with the Air OFF ..... lower the stylus onto a still record. UNMUTE and turn the volume up. Then have a friend turn your pump on as you keep your ear to the speaker cone, panel, horn - whatever you are using. Cheers - Good luck on your adventure. |
I'm the maker of the AirProdigy air-bearing, linear-tracking arm and I note with interest the comments above. bdp24, you realise of course that Vic's Transfi Terminator was a 'copy' of Poul Ladegaard's pioneering low-pressure air bearing tonearm?! Of course that's not true - Vic's Terminator wasn't a direct copy - there were all sorts of modifications he made in order to improve on the original design. In particular he inverted the airtrack, which was a useful advance because the airtrack could then be positioned above the record to allow a much shorter 'glider' arm to be used which had the potential for enhancing sound quality. There are a number of high-pressure air-bearing arms on the market (such as the Cartridgeman arm) which use commercially produced cylindrical airbearings to achieve linear tracking of the cartridge across the record. These arms are expensive, heavy and cumbersome and require long sub-arms to track the cartridge over the record, since the bulky air-bearing section is located beyond the circumference of the record. I contend that my own version of the low-pressure, air bearing, linear-tracking tonearm is by no means a copy of the Terminator but introduces its own major enhancements. I'm not attempting to advertise my own product here but defend a project I've been developing over a long period. I had a Terminator for a number of years (I've owned many different tonearms) and was very impressed with the sound quality, which was better than all the pivot arms I'd heard. However there were a couple of aspects I was never really happy with, namely the size and weight. The Terminator's a bulky arm and weighs a lot! It's just not possible to mount it adequately on suspended sub-chassis decks and I particularly wanted to try it on my Thorens TD520. That's when I decided to try and create my own version. I have introduced what I believe are a number of major improvements to this genre of tonearms. The AirProdigy is unique in being cheap, light and compact and it sounds excellent! The airtrack is mounted over the platter so the glider-arm (as I call the sub-arm) can be short and light. The low weight of the glider-arm improves tracking and minimises resonances, which degrade sonic performance, by avoiding a long, tubular arm. I used CAD to craft specific parts for the arm by professional SLS 3D-printing so that I was not limited to the availability of different aluminium profiles. The nylon printed parts have the major benefits both of lightness and low resonance while also being rigid, strong and hard. Parts I designed that I am particularly proud of, and which help with my goal of straightforward setup, include the arm height mechanism and the levelling mechanism. So although the same in the general principle of operation to the Terminator, I believe my AirProdigy arm has major advantages in terms of applicability to a wide range of turntables, lightness, compactness and low price. And it sounds at least as good! |
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 millisecondsDelay .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! |
