ARMod II turntable project begins.

geezer · « **Reply #40 on:** 5 Mar 2009, 08:10 pm »

Quote from: rcag_ils on 5 Mar 2009, 08:08 pm

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Nope. Check any freshman physics book

The velocity is 90 degrees to the point to tangency of the record arc, therefore perpendicular to the point.

Nothing can be perpendicular to a point.

rcag_ils · « **Reply #41 on:** 5 Mar 2009, 09:14 pm »

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Nothing can be perpendicular to a point.

It can be when a line and a point form a 90 degree angle.

Wayner · « **Reply #42 on:** 6 Mar 2009, 09:17 pm »

I am very close to up-chucking the Rega R200 arm. I'm deciding that it is just a pain in the ars and it is going to be nothing but trouble. Not only is the anti-skating askew, the little bit of interconnect left still has a broken wire. I'm thinking I will just feel allot better if I just walk over to the garbage can and do the old bombs away trick. The cueing arm is also a bit tricky and I see an accident in the waiting.

With the board drilled for a Rega arm, that leaves me with 2 choices, the RB250 or the new RB301. Can anyone hear tell me why I should spend the extra 200 for the 301?

Wayner

turkey · « **Reply #43 on:** 6 Mar 2009, 09:55 pm »

Quote from: rcag_ils on 5 Mar 2009, 09:14 pm

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Nothing can be perpendicular to a point.

It can be when a line and a point form a 90 degree angle.

How can a line and a point form an angle?

rcag_ils · « **Reply #44 on:** 6 Mar 2009, 11:33 pm »

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How can a line and a point form an angle?

In a circle it can.

Since a tangent only touches the circle at exactly one and only one point, that point must be perpendicular to a radius, in turn forms a 90 degree angle.

rcag_ils · « **Reply #45 on:** 6 Mar 2009, 11:44 pm »

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I am very close to up-chucking the Rega R200 arm. I'm deciding that it is just a pain in the ars and it is going to be nothing but trouble. Not only is the anti-skating askew, the little bit of interconnect left still has a broken wire. I'm thinking I will just feel allot better if I just walk over to the garbage can and do the old bombs away trick. The cueing arm is also a bit tricky and I see an accident in the waiting

OK, I am just kidding, it reminds me what I went through several months ago.

I don't know what to tell you about the anti-skate, other than disassemble the base and reset the anti-skate to zero, then use your hanging weight method.

BUT, to do that, you would have to desolder all five wires off the pins from the connector side, then you may not have enough wire left to resolder them back on, then it may escalate into fishing in all new wires, and redo the headshell part of it too. It'll take hours if not days.

I don't know too much about the RB301, it's new and I haven't done much studying on it, but the RB250 seems like a good choice, I am thinking about getting one myself.

Wayner · « **Reply #46 on:** 7 Mar 2009, 06:02 pm »

It lives!

There are still numerous tweaks. The belt started making noise, the anti-skate weight isn't quite right and I have a spacer piece in the headshell backwards and it is putting a bow into the headpiece.

Depression, recession...if it ain't one thing it's another...oh brother!

Wayner

turkey · « **Reply #47 on:** 8 Mar 2009, 03:43 pm »

Quote from: rcag_ils on 6 Mar 2009, 11:33 pm

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How can a line and a point form an angle?

In a circle it can.

Since a tangent only touches the circle at exactly one and only one point, that point must be perpendicular to a radius, in turn forms a 90 degree angle.

That's not a line and a point. It's a line and a line (segment). They meet at a point (two lines are either parallel, coincident, or intersect at a point) and form an angle.

Wayner · « **Reply #48 on:** 8 Mar 2009, 06:24 pm »

I spent much of yesterday tweaking the new table design. If you ever build a table, the motor is the enemy. If you can feel a vibration on the plinth, it will end up in the tonearm, mimicking hum or close frequency mechanical noise.

This morning brought a new thought to the design and I have now implemented that idea into the design with resounding results. However, I can't show you the design, it's kind of a secret right now.

As you can tell from the pictures, I did use the R200 arm. I decided I wasn't going to let the beast win. I have a different approach idea to the main problem (interconnect) and that worked.

If you decide to buy an R200 tonearm, there will be 2 problems with it. The first was the anti-skate timing belt inside the assembly. The second is the interconnect. The wire that was used has horrible tear strength and it will be broken internally somewhere close to the connection on the tonearm. Unless you think this arm has some sonic virtues over an RB250 or RB300/301, you might want to reconsider. You may be in for some not so fun of times. I must have 15 hours in the arm. But all is well now.

The table has very nice bass, and is airy at the same time, which seems kind of funny. Motor noise is all but gone. Mechanical noise is gone. There is no hum. I have one of my AT440MLas in it now and is performing as I am used to.

The last tweak for this machine is a cutting board or granite slab under it all to make it really complete.

Wayner

rcag_ils · « **Reply #49 on:** 8 Mar 2009, 06:37 pm »

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In a circle it can.

Since a tangent only touches the circle at exactly one and only one point, that point must be perpendicular to a radius, in turn forms a 90 degree angle.

That's not a line and a point. It's a line and a line (segment). They meet at a point (two lines are either parallel, coincident, or intersect at a point) and form an angle.

It is a point and a line, the point of tangency in a circle just happens to be part of the radius of that circle.

A series of points form a line, not the other way around.

rcag_ils · « **Reply #50 on:** 8 Mar 2009, 06:50 pm »

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The table has very nice bass

I suspect the nice bass is from the R200 tonearm, mine has very nice bass as well, my previous arm on the same table didn't has bass like the R200, it's still nice, but the bass signature was different.

charmerci · « **Reply #51 on:** 8 Mar 2009, 09:02 pm »

Wayne,

That TT looks simply wonderful - but can't you get a different anti-skate weight? It looks so ugly compared to the rest of the table. Maybe you can hang one of those great sounding blue capacitors instead.

TheChairGuy · « **Reply #52 on:** 8 Mar 2009, 11:31 pm »

Quote from: Wayner on 8 Mar 2009, 06:24 pm

I spent much of yesterday tweaking the new table design. If you ever build a table, the motor is the enemy. If you can feel a vibration on the plinth, it will end up in the tonearm, mimicking hum or close frequency mechanical noise.

Spot on. Probably the most important thing to get dead right, or minimize, is motor vibrations for any table. After that it's a lot of nuance involved in the design. The nuance is important, but it mostly adds up to respective likes and dislikes largely after the motor (one you have feedback tamed, too)

John

Wayner · « **Reply #53 on:** 9 Mar 2009, 10:22 pm »

Yes, I have designed a new dead-man weight bracket and I've had to put the stabilizer rod up from the bottom thru the weight to keep the damn thing from rocking back and forth. I had to do this on the Empire so why did I think I didn't need to do it on this table is beyond me. The new bracket will not bend as the other one did, it was acting more like a fishing rod. New bracket lets the weight easily and smoothly move up and down. I will post more pictures of this when I have it done and all the paperwork for the patent application is done. If anyone from VPI or Music Hall, etc. want in the design, drop me a PM......HA, HA, ha.

Wayner aa

Wayner · « **Reply #54 on:** 11 Mar 2009, 12:50 am »

Here is the new bracket and dead-man weight.

the filament going thru the eyelet is attached to the outside portion of the tonearm horizontal pivot. The attachment point must be pass the pivot point or it won't work. The filament is then fed thru the fishing weight and tied to a very tiny washer (just acting as a stop). From underneath the plinth, I have an .009" dia "E" string wire from a guitar that also goes thru the fishing weight and then up thru the eyelet in the bracket. This keeps the weight from swaying. The weight acts like a fireman sliding down (and up) the pole. The bracket is stiff to keep from having any kind of moment.

Wayner

Wayner · « **Reply #55 on:** 11 Mar 2009, 09:29 pm »

Close to complete, I thought I would show some pictures of the arm just sitting there as the disc spins, showing the effectiveness of the anti-skating device. Also notice the position of the weight in the 3 different views. It is really well balanced.

and maybe a better shot at the dead-man tower.

I have also been busy getting rid of some tonearm vibrations, one being the unused and broken anti-skating control knob, which is now glued down.

Wayner

Wayner · « **Reply #56 on:** 7 May 2009, 02:09 pm »

ARmod II has had a change in design. I could not make the attahed motor assembly quiet enough to my liking, so now it uses the SAMM (Stand Alone Motor Mount) from ARmod and it is awesome.

All the framing is gone and tennis balls have been put in place (3) under the plinth (glued on). Seams to work well.

Back to more listening.

Wayner

turkey · « **Reply #57 on:** 7 May 2009, 02:19 pm »

Quote from: Wayner on 7 May 2009, 02:09 pm

All the framing is gone and tennis balls have been put in place (3) under the plinth (glued on). Seams to work well.

That's pretty clever. They provide the spring and damping all at once.

So have you tried different brands of tennis balls to see which sounds the best?

Wayner · « **Reply #58 on:** 7 May 2009, 05:05 pm »

These are Wilson, I think. Cost was under $3 for 3 balls. This machine has tremendous bass, with almost no rumble. I do not have the dead-man anti-skate weight just right, slightly too heavy. That will be this afternoons project. I don't like filing on lead. Breathe deeply..............

Maybe that explains alot about my self.

Wayner

Wayner · « **Reply #59 on:** 8 May 2009, 03:39 pm »

Final tweaks are done and I added a skirt around the 3 sides to hide the tennis balls. Dead-man weight has also been adjusted. This table will share the same motor that the original ARMod uses.

Wayner