Printing Luxman L-100 Balance Ring

[merder]

I have two L100Us. Both balance rings are broken. I've decided to try to draft/print one. I do not have the protrusion to measure as that is what's broken off on both of mine, so I've relied on eBay pictures of a balance ring (that the seller was asking $100 for, which is extortion, IMO) and the remnants of the one I have.

We just had an awful storm here in New England and we've been without power for a few days... but now we're back, the resin has arrived, and it's time for the trial run.

I don't expect these to be perfect I am not a draftsman, I am not a professional 3d print farm, I am not great with CAD and I don't have a whole ring to measure. But I do expect it to perform and look better than not having anything there. When I'm done, I'll upload the CAD file, likely on Thingiverse, so anyone can download and print it. I am going to be printing it with Rigid 4000 resin on a Form Labs Form 2 resin printer, it will then be photocured in a kiln. The resin is grey/white, not the coffee color of the original, I'm going to try a few things to color it once it's out.

I have not yet drafted the pot splines. Before I do that, I'm going to find out how much this shrinks in the curing process. I'm printing three copies at slightly increasing scales to test out best fit. After that, I'll dowload a similar CAD file from McMaster Carr (hope they still allow that) and use that to subtract the splines from the current model. Also, the blance pot is actually divided in quarters, I might slot the insert sleeve to match up the gaps. We'll see.

Here's the CAD drawing.



Here's the amp hanging out w/some friends. I'm also probably going to print the EQ tilt knob, the one on here is not original, and I do have one on the other L100 from which I can measure.

 

[ivandezande]

Those always break....print a few and put them on eBay to save other units!

 

[merder]

This is the first actual ring that I've printed.


Once I put it on the amp, I realized I'd not drafted the 'gooseneck' that this requires to fit in the recess for the balance knob. The 'pointer' is also not shaped correctly and it's too long. But the overall dims re: the rest of it are pretty good, it fits snugly.

I printed another after I corrected the original CAD model to add the gooseneck... fits OK but shape's off. Back to the CAD program...

Since I was drafting and printing, I decided to draft a button for a NAD 1000 preamp amp that I bought without one:

Works well...

Here's the balance ring printing. I'm always in awe that a solid part can emerge from a pool of goo...



Here's the latest version on the amp. I'm pretty happy with it, I need to figure out how to stain it brown.



And here's a picture of an original balance ring. I didn't realize that the point actual covers the little circle under 'balance'. I think that looks kind of weird, I'm happier with mine, but I guess I can extend that out. Anyway, this wasn't ever going to be perfect. I know enough to be dangerous about both 3d printing and drafting, not a pro at either.

EDIT: I redesigned the ring so that the top of the pointer covers about half of the 'o' under the word 'balance' (as the originals apparently do) and refined a couple offsets and some lofting. It looks more like the original ring now, and I think I was able to add reinforcement to the most fragile area w/o impeding functionality. If you are going to download from Thingiverse, the V5 version is probably the most like the original.



Here's the link to the STL on Thingiverse:

Luxman L-100U Balance Ring by tom_foolery

This is a replacement balance ring for the Luxman L-100U integrated amplifier. It is not a prefect reproduction, but it works. V5 lengthens the pointer so that it obscures the balance circle on the front panel as, as far as I can tell, the original did. It also lengthens the pointer offset so...

www.thingiverse.com

 

[Powertech]

Looks like an excellent job. You should be proud of yourself.

 

[merder]

Looks like an excellent job. You should be proud of yourself.

It's an OK job, but after using it for a bit I redesigned it and uploaded a new STL. Thank you for your kind words!