The Talking Machine Forum — For All Antique Phonographs & Recordings

Here is where I buy the gasket material. I've circled the one I use. Notice the product below it has a harder durometer. Interesting. McMaster Carr's website is www.McMaster.com

Just to bring the topic of "durometer" into perspective, I've included the following chart that compares hardness to known objects. The durometer values in the catalog cut above are related to the "Shore A" scale I believe.

This was great! I have always admired your talents and your writing ability, too. Do you plan to have your ears calibrated so you can continue tone tests with greater accuracy?
Dave D

JerryVan wrote:

Marco Gilardetti wrote:Oh, I see, underscore, not hyphen. Formally he ships "worldwide", but then his list of excluded countries is so long that basically the whole Europe is excluded. I cannot even take a look at these famous diaphragms. Not of any interest to me, at this point.

The diaphragms are from this seller: https://www.ebay.com/itm/Victor-Orthoph ... SwJJVZqzRO Seller name: bobb7476

Thanks Jerry, but these look like generic spider-less replacements, easily available also in Europe. Thanks for the link anyway.

Dave D wrote:This was great! I have always admired your talents and your writing ability, too. Do you plan to have your ears calibrated so you can continue tone tests with greater accuracy?
Dave D

Dave,

Thanks for your kind comments and enthusiasm! I'm looking into the calibration process... (honestly, I didn't know about this when I made my original "calibration" comment)

JerryVan wrote:

Dave D wrote:This was great! I have always admired your talents and your writing ability, too. Do you plan to have your ears calibrated so you can continue tone tests with greater accuracy?
Dave D

Dave,

Thanks for your kind comments and enthusiasm! I'm looking into the calibration process... (honestly, I didn't know about this when I made my original "calibration" comment)

Eh? What?

Bill

From my experiences I can state that there are indeed differences in early vs. later production Orthophonic diaphragms. Brass and early potmetal reproducers do have thinner diaphragms than later potmetal ones; early potmetal being defined as those which have the needle setscrew coming straight out to the front face of the reproducer, as opposed to the later style in which the screw is set at an angle. Some years ago I rebuilt several of both types and took care to note differences such as diaphragm thickness but unfortunately I can no longer remember the numbers. I have noted other differences such as brass-bodied ones with potmetal rings as well as with brass rings.

Early potmetal reproducers use steel bushings for the outer bearing races with magnetized bearings. Later potmetal reproducers use brass outer races and have a steel washer against the steel balls and a rubber washer beetween the outside of the steel washer and the dust cap. A brass reproducer has the outer races machined into the steel bearing block rather than having inserts. They also use magnetized bearings.

As far as sound, there are differences between brass/first generation potmetal and second generation potmetal reproducers. They can be subtle, but they are discernable when doing A-B testing. For several years my 8-30 has been equipped with a later generation potmetal reproducer which, to me, is the best overall performer in my collection.

Jim,

Thanks for sharing your observations... I find this very helpful regarding Orthophonic taxonomy.



Frank