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Here it is, "in action". I'll probably blacken the retaining ring eventually.

Jerry -

Thanks for sharing your experiences and techniques !

Regarding the diaphragm gaskets: the few that I've been able to disassemble ( pot-metal ), the original seem to be a wax-impregnated paper-board / cardstock, less than 0.020" thick ( comparing to setting point-gap on my stovebolt Chevy six ).

These original rings were NOT resilient, I think mostly intended to create an air-tight seal between the reproducer body and the duralumin diaphragm.


Wyatt Markus is pretty emphatic that all the flexibility is supposed to be a property of the diaphragm, not of the "gaskets", as with a mica-diaphragm soundbox.


I agree with your sentiment about not wanting the spanner-ring sitting proud from the back-plate / front cover.


I wish I had the machine shop skills and equipment to make things like die-punches for this kind of work...


Are you going to do some "Tone-Tests" to compare against a Victor diaphragm ?



I am curious whether anyone has tried carefully punching holes in the diaphragm, to use the OEM spider- tabs ? It looks to me like Victor's original design was to use the holes / tabs to physically locate and secure the spider, and then the shellac to make things air-tight.

Somewhere in my youth, I developed a mistrust of glues and cements...

Frank,


Thanks for your reply! This is the kind of discourse I was hoping for. I have noticed the original paper gaskets as well and have questioned my use of the silicone rubber. My thinking, (correct or incorrect), is that the .015" thickness that I use will compress minimally, and that under the pressure of the back plate, further compression will be nil, compared to the compliance of the duralumin diaphragm. The sealing nature of the rubber is what I thought would be an advantage. Still, I too have wondered about what dampening effects may still remain. I have another reproducer to rebuild, with what appears to be a perfect, original diaphragm. I'll try using paper in that one. By the way, most of the paper gaskets I've seen, (except for one), had paper that was coated with a dark brown or black substance. My assumption was that the coating was a very thin dressing of rubber, or other similarly resilient substance, (you suggest wax, which seems reasonable), that has gone hard over the years.

As to the diaphragms, I have conducted a non-scientific "tone test", using my ears, which are currently uncalibrated. Along with the brass reproducer above, I have also recently rebuilt a pot metal version, still using its original diaphragm. Using the same record, on the same machine, I find that the original may have a slightly mellower tone. Or, it may be my imagination. Or, might also be the difference between pot metal & brass reproducers.

BTW, as you can see in my photos, the limit screw is missing from the bearing block. There were 2 sizes used. One I believe was a 1-72. The missing one here, is smaller than that. Haven't tried it yet, but I'm guessing maybe it's an 0-80. Anybody know for sure?

Jerry,

What you say about the compression of the silicone gaskets to point of minimal compliance sounds logical to me.

The original gasket rings I've witnessed are black on the outside, and perhaps grayish-brown in the middle where one had broken.


I seem to remember reading a comment somewhere on this forum about the repro diaphragms being slightly thicker than original VTM parts ?

By any chance have you mic'd an original vs a repro to see ?


Certainly, overhauling an OSB and getting it set-up with decent bearings, clean, air-tight diaphragm, good gaskets, make the whole thing air-tight, and getting a supple isolator on it HAS to make it sound pretty darned good...

Whether or not it is equal to a perfect original, might be splitting hairs too fine to be quantified ?



Regarding the bearing "boxes": have you run across any with little flat-washers between the bearing balls and the outer rubber cushions ?

The other year, I got brave, and disassembled the very nice original pot-metal OSB from my great-grandmother's 8-12, and found such washers between the fossilized rubber cushions and the bearing balls. I am dead certain that I was the first person to open those bearings since the machine left Camden in late 1927. This is the ONLY OSB among a dozen or so that I have found these washers in.

Their presence makes sense to me, as the ones w/o the washers but having cushions, have had the bearing balls deeply embeded in the rubber, which would seem to allow for some slop between the tapering needle-bar journal and the balls...

Frank

Might it be possible for other people to know from whom these materials were purchased?

A search on ebay with the keywords "orthophonic diaphragm" gives zero results worldwide, and there is no seller registered under the name "cyber-tigger" (and "cyber-tiger" as well").

Marco Gilardetti wrote:Might it be possible for other people to know from whom these materials were purchased?

A search on ebay with the keywords "orthophonic diaphragm" gives zero results worldwide, and there is no seller registered under the name "cyber-tigger" (and "cyber-tiger" as well").

Here you are, Marco: https://www.ebay.com/usr/cyber_tigger I bought several bits and pieces from him, including a full orthophonic reproducer, which sounds great.

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.

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

De Soto Frank wrote:Jerry,

What you say about the compression of the silicone gaskets to point of minimal compliance sounds logical to me.

The original gasket rings I've witnessed are black on the outside, and perhaps grayish-brown in the middle where one had broken.


I seem to remember reading a comment somewhere on this forum about the repro diaphragms being slightly thicker than original VTM parts ?

By any chance have you mic'd an original vs a repro to see ?


Certainly, overhauling an OSB and getting it set-up with decent bearings, clean, air-tight diaphragm, good gaskets, make the whole thing air-tight, and getting a supple isolator on it HAS to make it sound pretty darned good...

Whether or not it is equal to a perfect original, might be splitting hairs too fine to be quantified ?



Regarding the bearing "boxes": have you run across any with little flat-washers between the bearing balls and the outer rubber cushions ?

The other year, I got brave, and disassembled the very nice original pot-metal OSB from my great-grandmother's 8-12, and found such washers between the fossilized rubber cushions and the bearing balls. I am dead certain that I was the first person to open those bearings since the machine left Camden in late 1927. This is the ONLY OSB among a dozen or so that I have found these washers in.

Their presence makes sense to me, as the ones w/o the washers but having cushions, have had the bearing balls deeply embeded in the rubber, which would seem to allow for some slop between the tapering needle-bar journal and the balls...

Frank

Frank,

I've never seen the washers under the rubber, as you describe. As you say, it makes sense. I usually leave the rubber out and have not had any bearings come loose, once put in place.

I have not measured the thickness of the new diaphragms. An original that I've measured recently came in at .002" thick. I have another reproduction, but it's wrapped up yet, and I like to leave it that way till I use it. Too easy to mess it up!