How do you weigh a reproducer, exactly?

[Cody K]

Well, not a reproducer, exactly, an Actuelle needle arm. I noted in a recent thread that I've been playing my Actuelle a lot more recently, and noticing that I hardly ever see black dust after playing a record. And yes, I'm one of those guys who checks the tip of the needle almost every time; I'm interested in keeping track of how much damage I'm doing to records by playing 78s on old equipment, because even though most of what I play isn't especially scarce right now, all of it will be someday. And I'd hate to see the prices on eBay in 2216 for Whiteman's Three O'Clock in the Morning (e.g.http://forum.talkingmachine.info/viewto ... =3&t=25048) -- ("$3,278,947? For a V-minus?! ARE YOU F'IN KIDDING ME?!") -- if we don't take at least decent care of the records we're playing now.

So this gets me thinking: I think I read somewhere (maybe here, but I can't find a source) that a stylus in a Victor Exhibition exerts a force of ~140lbs. per square inch. I don't know, I might have misremembered that, and if so, please let me know.

Questions: How has the weight of a needle on a record been measured traditionally? Are those '40s-vintage gauges you see on eBay accurate? Would one of these new-fangled, thin digital scales, the kind used (I'm told), by weed-mongers, propped up to the exact level of the turntable give an accurate reading from the pressure of the needle itself, or should some wider flat object be placed under the needle, tared, to spread the weight? Because I don't have that kind of scale, but I'm sure one of my neighbors does.

Also, does anyone know, or know of a source for, the average in-use weights psi for the Victor Exhibition, No. 2, and Orthophonic soundboxes? How much did the average weight of a tone-arm diminish as electronics became the default? I haven't been able to find that info so far.

Bottom line: How do you measure stylus weight? I'd appreciate any discussion about this, uh, pressing issue.

[CarlosV]

The needle weight on modern turntables is measured with a balance, you sit the tip of the needle in a little hole on one end and adjust the sliding weight on the other end until it is level. These balances were made by Shure and other manufacturers. They will not work for old pick-ups, as they are normally limited to a maximum of 5 grams, while old gramophone reproducers on their arms would weigh 100 to 300 grams. I never saw any gauge for weighing gramophone soundboxes.

Weight is only a part of the response, though. Alignment, followed by static and dynamic pressure are the key wearout factors on turntables. As an example, the cartridges of the microgroove LPs had to be significantly lighter than those for 78s simply because the groove radius reduced from 3 mil to 1 mil, which would increase the contact pressure by a factor of 9 if the soundbox weight would be kept the same. So, even though modern turntable pickups weigh much less, the pressure they exert over the grooves is not much lower than that of a light gramophone soundbox.

Alignment of the turntable is even more relevant as a wear factor, it is relatively easy to correct but it is also widely neglected by most collectors. A misaligned soundbox that is not perpendicular to the plane of the record will eat out the side of the groove almost immediately, as well as a gramophone that is not level and pushes the arm on in or outward during play will also chew grooves.

The fact is that ALL records will be worn out by being played, either by a modern turntable or by an old gramophone. There are many publications that show before and after photographs of grooves played on old and modern phonographs. The wear is always observable. The good part of it is that it takes a significant amount of wear - or playing time - for its effects to start to be heard if the record is kept clean and played in good condition and well calibrated machines.

Your Actuelle is good to play vertical cut records - even though its arm is very heavy, if the sapphire is in good condition it will play Pathé discs many times before you can notice any wear. Pathé discs are very robust against wear. I would not use it to play lateral cut records, though: the arm's lateral compliance is too low.

[52089]

As you said, tracking weight is easily measured with a $10 pocket digital scale from Harbor Freight. You can generally place it right on the turntable and lower the reproducer right onto it, though with a Diamond Disc machine you might have to make adjustments to get enough clearance.

PSI is another story. You would have to know the approximate surface area of the contact point. I suspect that's documented somewhere, but I don't know where.

[JerryVan]

PSI figures are not relevant. Since the surface area of needle contact will be essentially the same for all machines, and only the stylus weight will vary, all you really need to know for comparison purposes is the stylus weight, usually measured in grams or ounces. In mathematic terms, the stylus contact area cancels out of the equation since it remains constant. The psi figure was probably stated only to be sensationalistic.

[victorIIvictor]

In the USA, at least, the Actuelle label (later renamed Pathé Actuelle) was introduced as Pathé's entry into the lateral cut disc market. I may be mistaken, I don't believe Cody's Actuelle machine can play anything other than lateral cut discs.

I would think tracing error would be responsible for more record wear than stylus pressure.

Best wishes, Mark

[52089]

In the USA, at least, the Actuelle label (later renamed Pathé Actuelle) was introduced as Pathé's entry into the lateral cut disc market. I may be mistaken, I don't believe Cody's Actuelle machine can play anything other than lateral cut discs.

I would think tracing error would be responsible for more record wear than stylus pressure.

Best wishes, Mark

The Actuelle phonographs play both vertical and lateral groove records by a simple adjustment on the tonearm.

[Lucius1958]

In the USA, at least, the Actuelle label (later renamed Pathé Actuelle) was introduced as Pathé's entry into the lateral cut disc market. I may be mistaken, I don't believe Cody's Actuelle machine can play anything other than lateral cut discs.

I would think tracing error would be responsible for more record wear than stylus pressure.

Best wishes, Mark

The Actuelle phonographs play both vertical and lateral groove records by a simple adjustment on the tonearm.

And, of course, a change of stylus...

Bill

[VintageTechnologies]

I think a typical 78rpm stylus has a radius of 3 mil. If the tip of a stylus was flat (which it never is, it will be spherical or eliptical) , you could simply calculate the surface area of the stylus using the formula Area = Pi * R * R. Being curved, the actual stylus tip area contacting the groove will be even less. Dividing the surface area into the weight would give you some idea of the PSI. Of course, a steel needle would quickly wear down to conform to the groove and provide a bit more surface area.

Years ago I saw an advertisement that stated the pressure for even a "modern" pickup was in the tons per square inch! I don't doubt that. It would be much worse for the acoustic reproducers that weigh ounces instead of grams.

[Cody K]

Hi folks -- Sorry to have dropped this question here and then disappeared -- it's been a distracting week. I appreciate all the advice you've given. My takeaway from it is that I can stop pondering PSI issues, which aren't as pertinent as I'd thought.

It's a shame there's such a lack of detailed information about the Actuelle machines, so that fine-tuning the apparatus is pretty much a matter of trial and error; my impression is that, when properly adjusted, there's a sweet spot on the Actuelle (which does adjust by balancing between the cone and the stylus, much like a modern turntable such as Carlos mentioned) that seems to minimize record wear. The danger, of course, is that if overadjusted in favor of the cone end, the stylus might well track too lightly, and ride the walls of a groove rather than the bottom, increasing the risk of tracking error (as Mark mentioned) and record damage. This is what led me to wonder about the relative weights of common reproducers, which will provide some idea of the weight considered optimal when the machines were new. I'll borrow my neighbor's scale.

Mark, the funny thing is, I don't have a sapphire, and only one Pathé vertical record anyway, so my use of the Actuelle is limited to lateral discs; and again, I'm seeing very little, if any, black dust after playing a record on it -- though of course that's not a definitive gauge of damage, just a convenient one that I tend to check almost compulsively after playing a record on any machine. The adjustment of the two little screws on either side of the needle chuck, that are somewhat analagous to the balance-spring screws on an ordinary reproducer (though there aren't a pair of springs here) does seem to make a difference in enhancing compliance.

I do have the stylus that plays Edison discs on the Actuelle, but I'm not much interested in Edison discs, so I really never use it. Anyway, that's a subject for another day.

Thanks again for the information...

[Jerry B.]

This thread reminds me of something I read as a young collector. I read that with a new needle in an Exhibition, you can not lift the reproducer with the needle resting on your fingertip. I read that and thought that it was ridiculous so I tried it. The pain was immediate! I couldn't let it rest on my fingertip let alone trying to lift the Exhibition. Try it!

Jerry B.