Air compressor for tangential tonearm

[Fidel Costar]

Hi all,

My good friend Karel, a very talented handyman, is building a tangential tonearm on a cushion of air (which I hope a copy will be used on one of my turntables) somewhat in the style of this one:
http: / / www.trans-fi.com/terminatortonearm.htm

So it seems we have to use an air compressor or something like that. Area in which I know nothing. Should we use an air pump or a compressor for fish tank or something else? What features should we consider? And of course, how much does it cost? Apparently, it is desirable that the airflow of the unit is adjustable according to the arm with which it is used.

For audiophile use, it is clear that an appliance as quiet as possible is desirable.

Thanks in advance for your help.

Regards,

Cristobal

[indianajo]

You adjust the airflow with a needle valve, like the ones from mcmaster.com (expensive) or electronicsurplus.com (cheap but will be gone someday). Gate valve are some use for fine adjustments, but ball valves don't have fine adjustment.
Fan based "compressors" should provide enough pressure, but if you use a diaphragm compressor or something with a piston, you will need a large enough tank to even out the pressure pulses. Squirrel cage blowers provide a little more pressure than an actual axial fan.
Be sure to use inlet and outlet filtration and an air dryer. You don't want dirt or moisture in this bearing. Self draining dryers are best unless you like conforming to rigid preventative maintenance. schedules. Installing one dryer, followed by 25' of tubing or a heat exchanger, followed by another dryer, gets you the driest air.

[Triodethom]

May I suggest using a tank say five gallon and fill it be for use . This will even out the flow and not have the noise and pulsing problems of pump. a regulator will be need but it is the quietest way to do it . given the small amount needed . Or use a 5 gallon bucket ( say one that drywall compound comes in ) set up like the web site with some poly fill in it to buffer the pulses of the pump. this will take time to fill up so start the pump before you want to listen but it will give you some buffer it you loose power .
I favor the high pressure tank with good regulator but that will be more expensive . Then emailing the web site and ask about pressure and flow amounts this should be in psi and cfm amounts if the tell you in metric there are conversion software on the web.

[woodturner-fran]

Go to your local pet shops and get a good quality aquarium pump. Avoid the cheapest ones - aim for the middle ground. Using a big shop compressor will give you hiss problems at the arm, the aquarium pumps don't have this problem.

I'm using an "interpet av4" airvolution aquarium air pump, gives 2x 300 litres/hr at 0.23mbar. It's pretty quiet, but you will still need a buffer chamber like a 5l can.

Fran

[AVWERK]

You don,t say how much air pressure you need, but whatever you do you need to regulate just enough and no more air than needed.

You can use black PVC pipe say, 3" or 4" in dia. And make 1 or two in series at different lengths. One at 16" or one at 12" and the other series at 24". The idea is to smooth out pulses that come from whatever pump you use. Stuff one or both with Dacron pillow stuffing (synthetic material)
The dryer stuff will depend on whether you are using very high pressure (likely) to not needed with low pressure say, 3psi (unlikely) and the climate you live in.

Regards
David

[Sourdingue]

hello, I designed this air supply to my arm tangential diy ... if it can inspire you? a lot of air flow and very very quiet!
The link : DIY platine vinyle : Réalisations personnelles - DIY - Page 17