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 Post subject: How many 78s does a sapphire last?
PostPosted: Oct Wed 18, 2017 4:08 am 
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Joined: Jun Sat 18, 2016 3:21 am
Posts: 14
Ok, so I keep hearing in terms of hours how long a Sapphire needle lasts. In most modern guides here on the internet, I'm assuming when they say 100 hours, they are talking about playing time in LP's because 100 hours of 78s seems like too long for a Sapphire to last.
My Cartridge tracks at 10grams (I have a 1955 VM 1285 Tube Tri-O-Matic). So I doubt that my 78rpm needle is going to last 100 hours.
So how about in terms of Record Sides. How many 78 Record Sides does a Sapphire play until it needs replacing? 50? 100?
What do you think?


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Oct Wed 18, 2017 3:56 pm 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1252
Location: 77001
What is the phono cartridge in the V-M changer ?

V-M 1285 should have a 1200 changer.
Ten grams seems too heavy a tracking force.

Condition and cleanliness of the 78's will determine the
wear, also.
Assume you are playing "modern" 78's, not early ones.

Your ear will tell you when the stylus is worn.
As you implied, there is no specific # of hours of
playtime for sapphire styli.

Hotwax


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Oct Wed 18, 2017 4:48 pm 
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Joined: Jun Sat 18, 2016 3:21 am
Posts: 14
My cartridge is a rotating EV-88 (which take the Ronette type styli that clip in). It does indeed track at 10g which is normal for that cartridge, and before that I had an Astatic 64-TS which came with the player, another Rotating type which tracked at 8g (though I had it set waaaaay too light and therefor thought the distortion was due to a faulty cartridge).
I didn't even need to replace the Astatic but I did only because at the time, I thought it was dead. So after purchasing a scale I wanted to make sure the new cartridge was set at the correct tracking force. Once I adjusted it to 10g the cartridge sounded fine and no distortion etc. Here is a photo below:


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Oct Wed 18, 2017 6:21 pm 
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Joined: Jan Wed 16, 2013 12:04 am
Posts: 1252
Location: 77001
I thought that 10 g was heavy, unless there was
a crystal cart in there. Since the track force is correct,
only the record condition should affect stylus wear.
Hotwax


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Nov Tue 07, 2017 3:19 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 4127
Location: Berkley, Michigan
The 3-mil tip radius on a 78-rpm record wears slower than a 0.7-mil Lp tip. Being over three times larger, record contact is much greater so the force per square inch being exerted on the record is much less.

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That warm tube sound can usually be overcome by turning up the treble.


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Dec Mon 04, 2017 3:27 pm 
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Joined: Oct Mon 05, 2015 10:04 pm
Posts: 508
Location: Worcester Massachusetts
Some cartridges were specked at a higher tracking weight. The Internet myths about heavy tracking forces destroying records are just that, myths. 78's in their day were tracked very heavily, and still play fine. And if you try taking a cartridge that was designed to track heavy, you might not be happy with the results.

Track at the recommended weight, enjoy your records, and move beyond this Internet tracking weight obsession.

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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Jun Fri 15, 2018 1:40 am 
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Joined: May Thu 24, 2018 11:27 pm
Posts: 16
Location: NJ 08520
This is an interesting topic which deserves more comments. While the OP wanted to know about how many 78s can be safely played with a sapphire tip, the thread quickly turned into something else, like a tracking force discussion.
Researching phono equipment for over 40 years, I have not seen too many recommendations to (safely) allow 100 hours of playing time for a sapphire stylus tip. Most authors chose the conservative duration of only 50 hours. Surely, with care, as in cleanliness of both discs and stylus tips, we might get over 100 hours.
50 hours represents a large number of 78 rpm sides. About three minutes a side means about 20 sides in an hour (3 x 20). 50 times 20 equals 1000. Yes ! 1000 song or musical "selections"....That is a lot of fast spinning....

How can we optimize "safe playing" time ? Even scratchy looking discs deserve to be cleaned. Stylus brushes used after a few musical selections can wipe away the inevitable dust and debris of shellac spinning, which surely attach onto the stylus tip. Every now and then, inspect the stylus tip. A 10X or 20X loupe is not sufficient, but there are lighted 60X "mini-scopes" available on the bay for under $5. delivered to our doors. These 60X loupes are a bit of a strain to use as the eyepiece nearly touches our eye and the stylus must get very close to the magnifier inspection end. For some or many antique record players, this maintenance might be best done with the phono pickup cartridge removed from the tonearm, unless you can tilt your tonearm about 90 degrees up and get close to the "needle."

Once you get the actual stylus needle tip "in focus" via the inspection loupe, look to see that the tip is still round, without any chiseled looking angles seen on the sides. Looking smooth ? Keep on spinning and groovin'............


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Jun Fri 15, 2018 4:12 pm 
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Joined: Jun Sun 15, 2014 11:04 pm
Posts: 886
Location: Coos Bay, Oregon
IMO it is true that 100 hrs needle life for a sapphire is an exaggeration. If average record play time is 2 1/2 minutes and if 50 hours is a more realistic stylus life, that translates to 1200 plays.

However, as pointed out above, there are too many important variables involved that leave us with a number that can't be more accurate than "about". One other important variable not mentioned is the record material. Hard rubber, bakelite, shellac, celluloid, vinyl and other aggregates are some of the materials that discs have been made from though the years. The cartridge and its tracking force mentioned above by the poster indicate a period approximately between the 1940's and 1950's, where shellac and vinyl were the most common materials used. The shellac 78 rpm pressings could withstand far greater tracking forces due to their surface hardness and size of groove. Therefore, a sapphire stylus played exclusively on those type records could last for over a thousand plays. (There are those who argue that you should never use a jewel stylus on the harder records.) Vinyl 78 rpm records were made of a softer material and had a smaller groove size, allowing for much lighter tracking force, and an increase in the number of plays per needle.


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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Jun Sat 16, 2018 7:49 am 
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Joined: Aug Tue 24, 2010 8:56 pm
Posts: 4231
Location: Northeast Florida
For some cartridges, diamond 78 tips are available (I've bought them), not sure about the Ronette though

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 Post subject: Re: How many 78s does a sapphire last?
PostPosted: Jul Tue 03, 2018 2:22 am 
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Joined: May Thu 24, 2018 11:27 pm
Posts: 16
Location: NJ 08520
While diamond tips can certainly last for years, they do have a significant limitation. You know that needle term "skipping" which really means "sticking" in the groove ? Well, since diamonds are a fantastic conductor of heat, they also retain more heat than a sapphire tip. In many cases, when a diamond tip gets "stuck" in a groove, substituting a sapphire tip can result in the sapphire simply gliding through the stuck groove.

Of course, many of us know to inspect the sticking groove area closely to wisk or flick away the debris. If a genuine tough scratch is holding up the needle from passing around to keep on groovin', we can, under significant magnification, "scratch" through the obstructing scratch with a fine needle or an X-Acto blade. Practice is appropriate on expendable discs....

Do not underestimate the virtues of sapphire needles, my friends. Known to be "gentler on discs," jukebox "operator" techs often recommended sapphire tips. While requiring replacement regularly in certain venues, like popular pubs, the lowly sapphire tips succeeded in keeping the customers and owners happy. With a dancing or rowdy crowd, there was more than a little fear that the skipping records could cause some punching or kicking of the owner's juke machine, causing irreparable damage. If the jukebox stopped until repair, customers would find another juke joint....

Seeburg offered and sold many sapphire replacement styli...


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