Those work well. I've replaced/rehabbed a few with elements from Radio Shack. I have one or two laying here somewhere. They were only a few bucks and worked very nicely. I'm also certain they are the ones w2eny uses.
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D-104
- Thread starter kopcicle
- Start date
Those work well. I've replaced/rehabbed a few with elements from Radio Shack. I have one or two laying here somewhere. They were only a few bucks and worked very nicely. I'm also certain they are the ones w2eny uses.
I would start with identifying the alloy and thickness of the aluminum-foil diaphragm. Had this notion of visiting the local metal recycling with a mangled MC320 diaphragm. No way I can see to remove one without ruining it for any hope of reuse.
Those guys use a handheld tool that zaps a metal sample. Sorting metals by type is a big deal for a recycler. Pretty sure it creates a brief pulse of X-ray that gets is spectrum analyzed. Position and size of spectral peaks would indicate the identity of each ingredient of an alloy and the percent concentration of each.
From what I remember seeing, it would read out an aluminum alloy by type number.
Just ain't quite got a "round tuit" and sweet-talked one of those guys to zap a MC320 diaphragm and let me copy what it reads out.
Using a different alloy to make a new diaphragm would likely change the sound of the result.
Identifying the alloy is just the start. Where you would buy foil of a desired thickness and formulation is a whole 'nother can of worms to sort out.
I suspect strongly that rebuilding a cartridge with the original piezo element is the way to go. Manufacturing the Rochelle-salt crystal will be very inefficient at first. Until the exact, right 'recipe' is achieved, there will be a lot of reject crystals. You'll also have to set up a saw to cut the crystals into slabs so you can put them at right angles. The MC320 crystal element is a two-layer element with the axis of response for each layer perpendicular to the other. This increases output, and is mentioned in one or more of the patents I saw when I first got curious about this years ago. I had this notion that 1932 high-tech would be 21st-century garage tech.
Maybe, but the statistical nature of manufacturing will still rule the day. The more you make of any one thing, the fewer duds you produce.
And small batches will yield a lot of duds, percentage-wise.
The piezo element that went inside the cartridge came from a company called "Channel Industries". Seems to me they got bought and have a new name. Went looking to see if that piezo crystal could be bought from them, back before I figured out it's not the part that goes bad. This piece was not listed in any of their literature 10 or so years back when I last tracked them down.
Best of luck and 73
Those guys use a handheld tool that zaps a metal sample. Sorting metals by type is a big deal for a recycler. Pretty sure it creates a brief pulse of X-ray that gets is spectrum analyzed. Position and size of spectral peaks would indicate the identity of each ingredient of an alloy and the percent concentration of each.
From what I remember seeing, it would read out an aluminum alloy by type number.
Just ain't quite got a "round tuit" and sweet-talked one of those guys to zap a MC320 diaphragm and let me copy what it reads out.
Using a different alloy to make a new diaphragm would likely change the sound of the result.
Identifying the alloy is just the start. Where you would buy foil of a desired thickness and formulation is a whole 'nother can of worms to sort out.
I suspect strongly that rebuilding a cartridge with the original piezo element is the way to go. Manufacturing the Rochelle-salt crystal will be very inefficient at first. Until the exact, right 'recipe' is achieved, there will be a lot of reject crystals. You'll also have to set up a saw to cut the crystals into slabs so you can put them at right angles. The MC320 crystal element is a two-layer element with the axis of response for each layer perpendicular to the other. This increases output, and is mentioned in one or more of the patents I saw when I first got curious about this years ago. I had this notion that 1932 high-tech would be 21st-century garage tech.
Maybe, but the statistical nature of manufacturing will still rule the day. The more you make of any one thing, the fewer duds you produce.
And small batches will yield a lot of duds, percentage-wise.
The piezo element that went inside the cartridge came from a company called "Channel Industries". Seems to me they got bought and have a new name. Went looking to see if that piezo crystal could be bought from them, back before I figured out it's not the part that goes bad. This piece was not listed in any of their literature 10 or so years back when I last tracked them down.
Best of luck and 73
I have little to share since my last post, aside from finding an unmolested 1946 example that had a diaphragm about twice the thickness that we accept as normal. I also rebuilt an element from the late thirties maybe? It had the same very thick element with some foam within the element between the diaphragm and the “puck”. I redid that one as a ceramic. It works very well, but resides in my display case currently. It nearly replicates what I know to be good crystal response as is rebuilt by me. I only revive this thread as I found the great difference in the element thickness. I only wish we had a go to that knew what was up wayyyy back in the day. They are all likely passed on, sadly…
