Micro Seiki MA-100S tonearm info

[Zilch]

This is awesome!  But shouldn't it be in the DIY section?

[vleisman]

Next up is the mysterious adjustable weight / spring mechanism. For the life of me I am not sure what it does, but it's a beautifully designed and engineered thing. This is an adjustable arm that suits on top of the actual arm. The base covers the anti skate assembly but has no real influence there as far as I can see. There seems to be some relationship as the scale of adjustment is similar to the anti skate scale, from zero to 3.5ish.
The adjustment wheel on the front moves an aluminium slider inside the small arm, so basically moves weight closer to or further from the arm pivot point. Then there is a piece of gut that attaches to a weight on the one end and a spring on the other. This gut was loose on the weight end.



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[vleisman]

Once I figured out how it was pieced together the fix was relatively straightforward. Attach the new gut to the spring, route it over the little wheel through the hole and attach the weight.

Again the length is tricky and I made it a bit too short so the spring is permanently under a bit of tension. If I find out what it does I'll worry about that.



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[vleisman]

The headshell on this is an SME which is much too light for the arm. A highly technical fix of prestix is currently keeping things stable until I can source a proper headshell.



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[vleisman]

A few remaining niggles. The arm rest doesn't restrict or hold the arm at all, need to MacGyver something here.
The arm lift action is a bit jerky.


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[vleisman]

Big thanks to Fredeb for all his help and advice 

[fredeb]

Big thanks to Fredeb for all his help and advice 

Apologies for only looking in here now - been crazy busy .

Looks like you're doing well with getting everything functioning properly . Seems the only thing you need to sort is the arm-lift . Careful manual needle dropping for now .

I think that the spring with counter-weight being adjusted higher or lower would make small changes of resonant frequency of the needle in the groove , allowing tweaking of cartridges of differing compliance . If you have a couple of different cartridges , you can try them all on the same arm with the same head-shell . If the match between the arm and cartridge is bad , you can actually see the stylus vibrating unstably in the groove . Be sure to use an LP you don't mind messing up , from the junk pile as it were .

I have no idea what the effective mass of this arm is , but I'd guess high . Therefore a low compliance cart would be a good match . Another methods of matching would be changing the head-shell mass , like your prestick solution .  Easier to adjust with low compliance cartridges I think . More difficult to lower effective mass of high effective mass arms for high compliance cartridges . May as well start with a low dynamic compliance cart to start with .

Let us know how the setup sounds . 

[naboo]

The gut
that holds the weight
winds around the spiral plastic disc
that sits under the scale wheel.

The rusty wire
that holds the cork
that keeps the anger in.

Sorry, Ingvar got me going on Pink Floyd lyrics last night and I now I literally see them everywhere.

Nice job @vleisman and thanks for documenting. Maybe someday I'll get something fancy with wires