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Ladegaard tonearm - the real DIY winner
Ladegaard tonearm - the real DIY winner
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Old 10th January 2003, 01:17 PM   #11
livemusic is offline livemusic  Israel
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Hi Peter,
Re your questions:
Wires are Van der Hul MSS7 - very flexible, good an inexpensive.
There are five of them - one is grounding the wire guide tube.
Upper rail is just resting on VTA screw, contacting through teflon strip. Filling it with lead casting makes it massive and pretty inert.
I have no digital camera, so I cannot make some more pictures now. Hope attached drawing fragments give you an idea how it is built. The pivot bearing is made of old Technics tonearm: I cut the outer frame such the triangle plate with small pressed ajustable cone was made of it, and glued on the glider. The mating bearing part is cut of the inner frame, in form of short "legs" and glued again to lateral beam.
Good luck!
Michael
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Old 10th January 2003, 01:19 PM   #12
livemusic is offline livemusic  Israel
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One more picture:
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Old 18th May 2003, 03:26 PM   #13
livemusic is offline livemusic  Israel
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Default Decoupled counterweight

Conti, the famous Basis Vector tonearm designer claims all the linear trackers have an inherent drawback: the lateral effective mass is too high. May be, it makes sense, thinking about huge difference between its lateral and vertical effective mass; the cart has no such a divergence in vertical and horizontal compliance, it’s for sure. This is the reason why the linear tracker designers are trying to make the slider as light as possible, ecpecially for the highly comliant carts. So, I also started to figure out how to minimize tonearm lateral mass, couse my Shure V15R known by its high comliance.
Browsing through the Teres owners’ forum, I came across an interesting OL Silver tonearm modification by decoupling the counterweight from tonearm. Pretty simple idea: just hang the counterweight on the string under it's usual place on the tonearm tube. Though it was claimed, this increases the lateral effective mass, to my opinion, quite the reverse: it is getting lower. The tonearm effective mass is actually its moment of inertia around the pivot axle, in the other words, the inertial resistance of mass to externally applied force, causing the arm to rotate/move. So, if the lateral force is applied, the counterweight inertial reaction on the arm is close to zero, if hanged on the string, because the counterweight stays on place in the very first moment due to its inertia. The lateral dynamic effective mass may be about halved by this method; in my case the counterweight mass is roughly equal to the rest of the arm mass.
Anyway, I took the old arm lead counterweight, in form of short cylinder with the center hole, made a loop on the each side of dental floss piece (non-stretchable) and hanged it about 3.5 cm under its place on the arm.
Guys, It works!
The overall tonal balance just became right, slight distortions on the very hights are gone. Orchestral winds sound amazingly natural first time since I'm in vinyl. Each voice has now its own character and every bow touch is palpable. The arm deals with heavily eccentric records with ease.
Today, is sounds even better, after I made the weight in form of disc, in order to increase the pendulum length and thereby to lower the resonant frequency.
I'm very pleased with the improvement (at no-cost). Highly recommended!
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Old 18th May 2003, 04:26 PM   #14
fdegrove is offline fdegrove  Europe
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Default FOUCAULTS' PENDULUM.

Hi Michael,

Glad to see it improved your tonearm...

Still, I'd feel more comfortable if other ways were devised to achieve the same results.

It wil work fine as long as you're records are perfectly flat.

Cheers,
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Old 18th May 2003, 04:53 PM   #15
JOE DIRT® is offline JOE DIRT®  Canada
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6lb test fishing line works even better
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Old 18th May 2003, 09:05 PM   #16
livemusic is offline livemusic  Israel
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Default Re: FOUCAULTS' PENDULUM.

Quote:
Originally posted by fdegrove
Hi Michael,

Glad to see it improved your tonearm...

Still, I'd feel more comfortable if other ways were devised to achieve the same results.

It wil work fine as long as you're records are perfectly flat.

Hi Frank,
To my surprise, the arm works well on the warped and and eccentric records, much better than before.
Anyway, I started to think how to damp the pendulum oscillations...
Cheers,
Michael
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Old 18th May 2003, 10:27 PM   #17
fdegrove is offline fdegrove  Europe
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Default LA PENDULE...

Hi,

Quote:
Anyway, I started to think how to damp the pendulum oscillations...
Don't damp, prevent them...and it's easy Michael.
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Old 19th May 2003, 10:50 AM   #18
livemusic is offline livemusic  Israel
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Default Re: LA PENDULE...

Quote:
Originally posted by fdegrove
Hi,



Don't damp, prevent them...and it's easy Michael.

Let me guess... magnets?
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Old 19th May 2003, 03:28 PM   #19
fdegrove is offline fdegrove  Europe
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Default DECOUPLED COUNTERWEIGHT.

Hi,

Nope, no magnets on my mind...

You could lower the stem and the hole in the counterweight and decouple it using a pair of rubber O-rings.

Cheers,
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Old 19th May 2003, 07:03 PM   #20
livemusic is offline livemusic  Israel
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Thanks, Frank, I'll make a try.
BTW, the splitted platter is almoust ready. Oil filling turned to be a real mess, I just failed to address the leakage, and the oil/lead fill was substituted for sand/lead.
Cheers,
Michael
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