The Talking Machine Forum — For All Antique Phonographs & Recordings

Happy Friday, folks. I bet many of you are plotting your phono projects for the weekend.

This is a question for the Edison Diamond Disc phonograph enthusiasts among you. My fellow Edison enthusiast Larry Hollenberg (he of the amazing "True Tone" diaphragm) paid me a visit last Saturday and we did all sorts of listening and comparing of some of his diaphragms. Another issue that came up, though, is the proper "angle of attack" that the DD stylus should have on the record surface when a disc is being played. Larry believes that the bulk of the stylus platform (with its tail leading back to the diaphragm string) should ride parallel to the weight. However, when I am set up that way I get a loss of volume/detail and an increase in surface noise. But when I twist the diaphragm string a few turns (in order to shorten it) and thereby force the stylus to hit the record surface a bit "further back" I get a much richer and fuller sound and the surface noise largely disappears. (To be a bit more explicit: my favored orientation is for the hook to point towards the weight when a record is engaged, whereas Larry believes there should be no such angle).

How can anything that sounds so good be bad?

Is it because the increased tension on the shortened string creates all these good effects? Or is that because that's just the best angle for the DD stylus? Or a combination of the two? OR...does it vary stylus by stylus, given how they are wearing?

Inquiring Edison fans want to know.

Ralph

A great question, I hope you get some great observations!

From my obsession with modern audio, I've learned that stylus VTA (vertical tracking angle) can be critical to the end resultant sound of a recording. Of course this is related to modern vinyl records. My thoughts on DD records, minimal as they may be, are that even though the recordings are vertical cut, any interference from the sides of the stylus coming in contact with the sides of the groves because of front to back angular changes in the stylus, either from altering the angle of the stylus bar or because of stylus wear, could cause changes from added contact with the sides of the grove not only in surface noise , but also it seems that should affect the tone and loudness.

It'll be interesting to see if anyone has established the optimal vertical angle.

Fran

Thanks, Fran. Glad you believe from your own experience that this is a valid investigation--as we audiophiles attempt to tease as much good sound out of our grooves as possible.

Ralph

As a bit of background to how this may have occurred. I had sold Ralph a Standard Diaphragm but since I knew that the Two Ply version seemed to have superior sound I sent along a version I had here for a while. What I think happened is that when I have a poor diaphragm I save the hook eye screw to use in another.. Usually I also leave the linkage and then check it against the correct setting. (which I understand to be having the top of the stylus bar level to the bottom of the reproducer when the pin is raised up above the "V" a bit). Since I hadn't been offering any for some time the two ply version I sent evidently I hadn't gotten around to checking that setting. When we were moving diaphragms to test them, I installed the one Ralph liked best and realized the linkage was incorrectly set. The rear of the stylus bar was at a steep angle when the weight pin was raised to the normal operating position. To get it to be level with the top you had to raise the weight to its maximum height right at the bottom of the reproducer. This would have left no travel space for the weight and if a record had a warp or slight hump it would have cut into the surface. Thus I insisted that I return it home and fix the correct setting and return it.. Which I did.. My guess although only that was that the stylus condition may be compromised when set to the correct position, thus causing poorer sound. I am a bit mystified as well that it would sound good playing with the rear of the stylus bar at a steep angle. (but it may also have tilted the diamond point so that some of the worn portion wasn't contacting the record groove). The fact that it again plays fuller and clearer seems to indicate that the stylus when in the right position isn't reading the grooves well. But its only a guess.

Larry

I think most modern TT people call this angle the rake I find with original diaphragm the limiter pin in the middle of the loop there is a forward tip of the bar. I get great volume less surface noise and better tone over all.
my 2 cents
Dwight

Dwight, "forward tip of the bar" producing greater volume, tone-and less surface noise--describes my experience exactly. I really do think we are on to something here.

My current stylus might not be ideal and I'm going to find a replacement original that still has a good shape (causes no cutting), but given that your experience echoes mine, I think the "forward tip of the bar" is still a good general practice.

Ralph

P.S. Thanks, Dwight, for providing the correct terminology. I've been googling just now and see that "stylus rake angle" (or SRA) continues to be a big issue for audiophiles who still use turntables. One essay I found on line said that the correct adjustment has to do with finding the "sweet spot" on any stylus--and on later turntables this involves raising or lowering the angle of the tone arm. I think it was the same essay that said most modern styli find their "sweet spot" at 92 degrees, not 90. In short, it's something you do BY EAR. With Edison acoustic reproducers it's a bigger challenge as the adjustment (unless I'm missing something here) can only be effected by adjusting the length of string coming down from the diaphragm--or by attacking those good old Edison screws and bolts and altering how far the stylus can be lowered as it settles on the record surface (but that has its limits as the limit pin only has so much area it can travel inside the limit loop).

So, Larry, with all due respect (and it's considerable), I think that setting the stylus at a strict perpendicular to the record surface is not the way to go.

P.P.S. This is a great illustration of the joys--and agonies--that come with working with Edison's diamond-tipped machines. My hunch is that the lateral/steel needle phonographs don't have this problem as the disposable needles are pretty standard--and if one uses them beyond the suggested single plays then one can just loosen the nut, swivel them a bit, and you're back in business. No need to worry about SRA.

I can only go by what the Edison Repair & Service Manual says..

"To set the height of the Reproducer"

Refer to Figure 1. Place a Recreation of standard thickness on the turntable. Lower the reproducer into playing position and note the weight limit pin. This pin should be clear of the under side of the reproducer cup by a distance equal to the diameter of the pin. ( I set them a hair lower to give more room for the weight to float without cutting the record). With the pin at this distance below the cup casting, the diamond arm will be nearly parallel with the Re Creation. If the arm is badly out of parallel with the Recreation it shows that the diaphragm has become warped, or has some other defect and the reproducer should be sent to your jobber for replacement.

It then has a paragraph on how to set the height of the tone arm should it be off. (that only will work if the linkage is close to the original length). (my comments).

Larry

I will go with what my eyes and ears tell me and not a strictly literal interpretation of one particular manual. Is there anyone out there who adjusts the height of their Edison reproducer so that (when in play) the limit pin is only a limit pin's distance from the underside of the top of the reproducer? That is no safe distance at all. All contemporary photographic representations I have seen of Edison disc machines show the limit pin as CENTERED in the limit loop; by my estimation that's at about three limit pin diameters. Larry, even you have admitted that you set yours a "hair lower" so that the weight has some room to float and not cut the record.

There's some irony here. Larry, if I was a purist for original design I would not have sought out your diaphragm to begin with. I'm glad I did: it's a marvelous diaphragm. But in my continuing search for optimal sound I will always follow my ear--and when it comes to stylus angle, there MUST be some flexibility in determining it.

Ralph

Ralph,
I concur with your findings, if I am reading them correctly. While the needle bar in my reproducers are more or less horizontal when the limit pin is in the middle of the loop, I think the sound is better when the angle is a bit steeper, that is, maybe a pin diameter closer to the BOTTOM of the limit loop when in playing position. It also seems to me that different angle "sweet spots" are dependent on the particular diamond being used as well. The set-down levers in my machines have enough friction so that they will stay in almost any position off the vertical, so even though the horn height is set to be "correct" per the manual with the limit loop at the center when the lever is fully vertical, I find myself keeping the lever at some degree less than vertical, which slightly changes the stylus angle while still fully engaging the worm gear.

Ralph, I have a related question; how exactly do you go about twisting the diaphragm string to make it shorter? Do you remove remove the weight from the rear of the reproducer cup and wind it? Can it be this simple?

I realize now that the diaphragm string on mine is too long.

Fran