Ladegaard tonearm - the real DIY winner

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Ultimate Ladegaard.

After three modifications done, I still had a feeling the great potential of Paul Ladegaard design is not fully discovered. So, based on my previous experience and being deeply infected by DIY fever, I decided to go further. The main features of recent modification are:
1. CNC-machined acrylic headshell.
2. Carbon fiber arm wand, CLD damped externally, i.e. aluminum tube above carbon, placed between headshell and mount yoke, with the gap filled by silicone caulk. So the arm wand rigidity is not compromised.
3. Vertical knife-bearing consists of two small hobby knife blades, resting on V-shape bronze beads. The bearing fixed on slider laterally with two pre-tensioned fishing line pieces.
4. Silicone damped counterweight, with laterally split effective mass. Here we have the hollow aluminum housing with a steel ball, resting on spherical surface, inside it. The counterweight is partly filled with silicone fluid. Recent design is, in fact, a further development my pendylum-like counterweight, just heavily damped.
5. All the metal parts are drilled through for the weight reduction, in every possible place. The goal was to keep the lateral mass as low as possible.
In the end, the sonic improvement is major: big and tight bass, much better details, and even my pre-amp volume button is cranked lower now. I personally have had very much fun with my tonearm project, thanks to the brilliant Ladegaard design.
 

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Hi livemusic,

The arm looks very good, and I bet it sounds great ,too :)

The only small thing I can suggest is maybe to use screws that blend better with the looks of the rest of the arm, then the whole arm would look even better,
but that is only cosmetic, wouldn't have any influence on the sound at all.

Thinking of building something like the Ladegaard my self, so your arm is great for inspiration!

Very nice work ;)

cheers
 
fdegrove said:
Hi Micha,

How's bass performance?

Cheers,;)

Hi Frank,
Way better! First and foremost, because of more rigid bearing/armwand. What surprised me, no hights/sparkle deterioration, or boomy bass, in spite of high damping.
Splitted lateral mass idea works! Pendulum-like weight maybe was not free from drawbacks, but it was the step in right direction. I tried the simple decoupled counterweight, as you proposed: much worse, just sucks the life from music. This arm is tailored for my high compliance Shure, so I had to have low vertical effective mass, and to bring the lateral mass into compartible region also. Thanks for you criticism - it makes me creative.
:smash:
Michael
 
diyAudio Editor
Joined 2001
Paid Member
the brilliant design of Poul Ladegaard

After seeing an air track in my physics classes in university I have off and on for the last 30 years tried to come up with an air bearing arm that could be built simply. It always seemed that
a simple design could be done using an air track and thus avoid complicated machining.

I never came up with anything near as clever as this. As a lot of you know , I insist on projects being able to be built on the kitchen table. This one is for the DIY hall of fame.

Michael: I'll bet you could machine or grind the inside of the traveling angle so it is about half as heavy.
 
Variac said:


As a lot of you know , I insist on projects being able to be built on the kitchen table.

Hi Variac,
There is no such a complicating manufacturing in my project, as it may be seems. I just placed the order in local machine shop, and spent about 200 bucks, not more. Belive me, I have no special skills or tools, just primitive drilling press, files and vices. The only thing I always have on my kitchen table, is paper and pencil. I don't have to make any special effort for design, it simply never leaves me, floating around in my head, and it's for free.
I must confess, I've never been satisfied with the things done, call it insanity or infection: if it can be improved, why not? But most of the forum inmates are familiar with this disease symptoms, I suppose.
Regards,
Michael
 
Hi livemusic,

Excellent job. In fact, it has inspired me to sneak in a side project during my machining class. I had a few questions, though.

1) Concerning the arm itself: is the diameter critical? The Ladegaard diagram I found list a diameter of 7.5mm. Also, is the aluminum CLD damping tube just fit tightly around the carbon fiber tube, then caulked at the ends? Or did you goop the caulk between the the aluminum and carbon fiber?

2) How did you attach the bronze knife rest beads to the angle aluminum? Tension only?

3) Did you use the dimensions of the angle aluminum and hole spacing given on "Roscoe's Poul Ladegaard tonearm" diagram? Just curious to see if you found any improvements of materials during your experimentation.

Thank you for the inspiration, it really does look wonderful.
 
diyAudio Senior Member
Joined 2002
Hi,

I tried the simple decoupled counterweight, as you proposed: much worse, just sucks the life from music. This arm is tailored for my high compliance Shure, so I had to have low vertical effective mass, and to bring the lateral mass into compartible region also.

Yeah, too much damping from the decoupling of the counterweight would have that effect.
It's much more effective with low compliance cartridges such as MCs.

Congrats on the lovely job BTW.

Cheers,;)
 
Arm questions

Raoul said:

Excellent job. In fact, it has inspired me to sneak in a side project during my machining class. I had a few questions, though.


Hi Raoul,
1. Arm wand: the kite kit carbon tube I used has 7.8 mm diameter, and the outer thin wall Al tube leaves enough gap (about 0.5 mm) to fill it with the silicone caulk completely; otherways CLD basic principle (soft layer between two rigid surfaces) is simply lost. If you lucky to get the larger diameter carbon tube, go for it. Anyway, I think the arm wand damping is essential, I've heard enough of those nasty resonances through my headphones.
2. The bronze beads are glued to the Al angle with high grade epoxy glue ("plastic metal").
3. The slider dimentions and hole spacing are exactly as per Poul Ladegaard recommendations: works nicely!
One word about Al angles: try to get anodised profile, it is scratch proof.
Good luck with your project!
Michael
 
Wood makes miracles

To anyone wants to make top class arm at min cost:
Playing around with my Ladegaard project, I always felt that I need some more damping for armtube. I'm listening mostly through headphones, and it is a sort of magnifying glass: I heard sometimes resonance-like artifacts and complex orchestral crescendos were somewhat smeared and distorted. Theoretically, air gap is like a wall for the stylus-induced vibrations, bouncing them back and smearing the sound. Conventional gimbal design provides better path for vibrations through metal bearing, so, air tracker needs more damping, and more importantly, even damping thoughout frequency range. Double constraint layer damping, that I did for my carbon fiber armtube, mostly kills hights, doing little with low frequencies.
Hardwood was an obious choice, bearing in mind famous reputation of Schroder arms.
Boys, I'm not kidding: my most optimistic expectations were exceeded! New arm, made of bubinga impregnated by teak oil, sounds better than anything I heard before.
First, tracking is absolutely flawless, easily dealing with 3th "tortue" track on Hi-Fi test record. It allows the arm to go with no problem through complex fortissimo, like Prokofiev's first piano concert (Niagara falls soundwise), which always drove me mad before.
Second, the low-level details retrival, I never thought was lacking, which actually makes violins sound like violins with no trace of stillness (I'm speaking about timbres). Generally, it gives you feel of sound, reproduced "just right".
I keep saying: Ladegaard is DIY winner! And go wood!
 

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