Ladegaard tonearm - the real DIY winner

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
This thread has been an interesting read. The Ladegaard arm is so simple, and yet seems to offer very high performance. I'm all about cheap and good!

If anyone is still subscribing to this now almost 10 Yr old thread, I saw reference on this and another thread to using a tubular bearing assembly with a semi-circular arm mount on top of it. Basically replacing the alum. angle extrusions with some closely mating bits of pipe.

I like the idea of replacing both the bearing made with the extrusions, and the knife edge arm pivot with this even simpler arrangement. Has anyone ever tried to implement one of these?

Could they be made out of plastic pipe? or would possible static build-up be a killer here?

I looked up some PVC sched 40 pipe sizes and the 1 1/4" OD is just a tad too large to nest inside of a piece of 1 1/2" ID ( 1.660" Vs. 1.592" ) This could be easily "Lapped" into a very close fit with some elbow grease and a bit of abrasive. Seems to me that one could utilize this combination as the bearing and arm mount further simplifying the design.

Am I off base here?

What am I missing?

Curious, John
 
John, I think you have a brilliant idea. It will simplify the design.

Since you have the material, I would try it. There is nothing to loose.

I do not think you will have a static problem, but if you do, someone will give you some advise in coating the tubes with an antistatic material.

At the moment I am at a caravan site, and it occurred to me that one might make the pipe and sled from a sections of telescoping pipe used to support tents and awnings. Such pipes are in steel and aluminium. The Al would be preferred.
 
Thanks for the replies folks.

I too think that it would further simplify the whole concept. I did read about the telescoping IKEA curtain rod suggestion, but I don't recall the poster ever reporting back about it.

The idea of putting a coil of wire inside the plenum hadn't occured to me. I had thought about coating the outside of the plenum with something like what is used on the Mylar panels in an electrostatic speaker, and then grounding the plenum with a strip of Copper tape attached to the end. I envision this as being painted to hide the PVC anyway. I don't know but what that might be enough to aleviate any tendency to build a static charge.

Woodturner Fran, I saw the arm you built earlier in the thread. Are you still using it? have you tweaked it any to try to improve it. Your pictures were awfully small for my bad eyes to make out the small details. I'm glad to have any commentary from someone who's actually built one of these things.

My search for a suitable donor table is in progress, I have several ideas about how to make the arm adjustable enough to accomodate just about any old Cartridge (both overhang, and VTA), also my concept will allow a person to change arms in seconds. I suppose you could have an arm with a mono cart, one with your special cart, and an old conical for playing '78's if your so inclined....

My concept also would allow you to run your wire from the cart to the phono pre, without intermediary connections. As soon as I have a donor table to use, I plan to do a Sketchup with actual measurements to work from. This will also give at least some indication of what it may end up looking like.

Thanks for the encouragement.

John
 
They use coils of wire like that inside plastic ducting used for extraction systems.... should work AOK I think. Just anything tied back to mains earth.

I'm still using the arm shown - and without any mods since the last I posted here. It just works! I do find that if the arm starts "sticking" a bit as it plays, then usually either there's a lose connection on the airline or else the slide is a bit dusty. I take off the slide and clean both it and the support. That usually last about 6months.

I've looked there now for the pics I took - I should have them but can't see them at them at the moment...grrrr something odd here!! If I find them I can post them again, or if you need any I can re-take some. I have a short vid on youtube of the arm working too.

The arm is cheap to make but takes patience and time to get it made, lots of fiddly bits.

Also look at the opus cantus 3 thread - sometime I'll make one of those - and finish the schroder clone too!!


fran
 
Hey guys, just a quick troubleshooting question. I'm building a ladegaard variant (trying my hand at a terminator clone actually). I'm having some trouble with air flow.... I have this pump, a Top Fin 8000 air pump for aquariums with four outlets, which is 2.83 gpm/10.67 lpm and >2.32 psi. It seems that it should be more than adequate, don't you think? Thing is, when I hook it up directly to the arm it has no problem floating the carrier but when I connect it to a reservoir (to lose the vibrations from the pump being directly connected), it doesn't even come close.... The carrier gets stuck and you can feel that by moving it back and forth, it is not floating on a cushion of air as it should. The reservoir is made from a 6" piece of PVC, capped at both ends and tapped, it's about 4" long (standard plumbing drain stuff). Is this a question of "head pressure" on the air pump? Maybe the pump is not of high enough quality? It was very cheap for it's specs! Your advice?
 
I'm hesitant to post pics - my work is very amateurish! When I have a finished version worked out, I will post. I'm just in the prototype stage right now. The mechanism is supported by a square block of hardwood with aluminum plates bolted on and leveled by means of adjustable set screws on either side of the aluminum arm. The surfaces of the aluminum 90 degree pieces may not be adequate - I can kind of twist the top one and it has a bit of give or gap when there is no air flowing through. I'm going to fix this first. I'm hesitant to put another air pump on there - the specs of the one I have already dramatically exceeds the type of pumps I've seen/read of others using for the same setup.
 
This site is dedicated to amateurs.

A couple of years ago that was the thread of persons showing their ugly amplifiers with pride. How it works is what counts.

Electrons do not respect nearly placed wires with nice right angled corners.

This site is all about trying to do with a couple of dollars what others are doing with thousands.
 
So I retooled my carrier and discovered it had a leak and then I discovered that my reservoir had a leak! So, having fixed both of those things, I discovered that I had no problem floating the sled now. However, I had made a design decision for prototyping purposes that I would suspend the shaft from the sled by means of monofilament line, just to see if it would work. This seems to have been a bad decision as now the shaft just seems to "twist" instead of pulling the sled along the arm, causing skipping and getting stuck in a single groove. Looks like I'll have to go back to the drawing board and retool the sled as well. Put this squarely in the "seemed like a good idea at the time" category!
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.