New turntable project, ARCom II.......

Wayner · « **on:** 28 Nov 2011, 10:00 pm »

Thanks to AE and Dpump, I have all the parts for an ADC tonearm, the ALT-1. This arm got bad press, but after some analysis, I discovered that there simply was too much stuff rattling. First was the weight dial (which always seems to be a culprit), then the counterweight shaft, which has the counterweight piggybacking it and oddly, the counterweight can slide forward or backward on this assembly, plus the entire assembly moves forward and backward as well. I guess the engineer(s) thought that they could accomodate a wider range of cartridge weights.

Anyway, ARCom II is similar to ARCom, but has a more modified body, being constructed of 5/4 x 6 composite decking material. This stuff is made from recycled paper and is a breeze to machine. The inside hollows of the material (it has an extruded multi-hollow) is filled with lots of plasticlay. The bearing is from my last AR as is the sub-platter, and outer ring. For the time being, it will share ARCom's SAMM (Stand Alone Motor Module). The motor is a Hurst #3001-001, 300RPM syncrhronous with a .1245 dia. shaft, a perfect fit for the AR pulley (tricks are required to mate the two, however).

Tomorrow I will make it look prudy and get the cartridge mounted for it's trial run. One never knows how these things will turn out, but unless the arm has trouble (I doubt it), it should be up and running. It took as long loading the plasticlay as it did to build the stupid thing.

I have some Mumetal coming this weekend to treat the motor, tho it's hum field is quiet small being around a 7" radius. That puts the start of the field at the record label.

Wayner

orthobiz · « **Reply #1 on:** 29 Nov 2011, 01:13 am »

Is that an audiophile anti rumble carpet?

Maybe a "keep off the deck" sign is in order?

I'm just too clever tonight! Looks good Wayner.

Paul

BaMorin · « **Reply #2 on:** 29 Nov 2011, 01:53 pm »

What tricks would be needed to fit an AR pulley on the hurst 3001-001 motor? That's the stock motor on TheTurntable, ES-1, and ETL-1. The ADC arm is (after the arm tube) pretty much the same as the Linn LVV, as ADC built both arms. The pillar bearing assembly can be upgraded with a little internal machining to accept caged ball races vs the taper/looseball/plate assembly. and the vertical pivot ball races can be replaced with sapphire V jewel races. I'm interested in how you shield the motor with mumetal. Pics when you're done?

BaMorin · « **Reply #3 on:** 29 Nov 2011, 02:36 pm »

Oh, I forgot to mention that with a polishing technic and a different thrust bearing in the well will reduce rotaional drag to about a 1/3 from stock. Makes for a very quiet platter assembly, reduces belt jitter.

Wayner · « **Reply #4 on:** 8 Dec 2011, 10:03 pm »

Spent the day prettying up the pig, installed new motor, and other tweaks. Switch wont lay flat, but is secure. I will have to replace it the next time I go into the motor module. Total project cost: about $150.

Wayner