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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 25th Jan 2020, 11:14 am   #1
Edward Huggins
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Default To be NOS or not to be NOS?

Back in 1987 I bought a BSR SC12M cartridge from the then Tandy store in Lowestoft. It was on the basis that "one day this might come in handy".
Well some 33 years later, it has.
It's now replaced an ailing Garrrd GKS25 cartridge in the SP25 Mk2 deck in my Dynatron "Cordova" - one of only two transistor portable record players in my large collection.
I expected it would perform well - and indeed it does, with a smooth frequency range and a healthy output. It's certainly a good match to the 5 transistor amplifier.
Just how long this had been held in stock I do not know? By 1987 turtnables were in rapid decline due to the massive growth of the CD launched just 4 years earlier.
Even more to the point, just how long was it since my cartridge was actually made by BSR? They were in terminal decline by the early 1980s and had ceased cartridge production by about that same time.
It goes to show that buying a NOS crystal or ceamic cartridge now can be a bit of a hit and miss affair. Hopefully the remaining sellers will continue to offer a no-quibble replacement for those that will have failed over time. It is unlikely that very few of these Sellers will test, or have the equipment to be able to test these prior to sale, nowadays....
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Old 25th Jan 2020, 2:29 pm   #2
John10b
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Default Re: To be NOS or not to be NOS?

Hi Edward good that it has lasted all these years. Was it still in original package and kept in a relatively dry environment I wonder?
John
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Old 25th Jan 2020, 4:15 pm   #3
Nickthedentist
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Default Re: To be NOS or not to be NOS?

Don't forget that crystal cartridges don't seem to fare so well over the years as ceramics.

CPC and Maplin were selling SC12M (or similar) BSR cartridges until about 10 years ago ISTR. These, presumably, were some 25 years old.
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Old 25th Jan 2020, 5:52 pm   #4
BRASSBITS
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Default Re: To be NOS or not to be NOS?

Quote:
Originally Posted by Nickthedentist View Post
Don't forget that crystal cartridges don't seem to fare so well over the years as ceramics.

CPC and Maplin were selling SC12M (or similar) BSR cartridges until about 10 years ago ISTR. These, presumably, were some 25 years old.
the maplin ones were not genuine bsr
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Old 25th Jan 2020, 6:08 pm   #5
G6Tanuki
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Default Re: To be NOS or not to be NOS?

Yes, crystal cartridges [and mic inserts] generally don't age well - I've got a 1960s Shure amateur-radio fist-microphone here that originally had a crystal insert, which degraded to uselessness; to restore full transmit-modulation I had to replace the crystal insert with a modern electret insert and fit a couple of 'coin' cells to provide the necessary DC bias.
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Old 25th Jan 2020, 7:46 pm   #6
kalee20
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Default Re: To be NOS or not to be NOS?

Crystal cartridges may be quartz (should be OK) but may also be Rochelle salt (sodium potassium tartrate). The latter is not only soluble in water, but the stuff is also hygroscopic so it absorbs water from the atmosphere.

In a cartridge, it's fairly well protected. But there's limited sealing that can be done, else you'd never be able to apply stress to it to generate a voltage.

So, storage in a damp atmosphere is death to this type of transducer.
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Old 25th Jan 2020, 10:31 pm   #7
high_vacuum_house
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Default Re: To be NOS or not to be NOS?

The crystal pickup cartridge used in the Tefifon players I believe is a Rochelle salt and is a common failure point in these machines. The crystal element turns to mush. I have a few of these pickups that are dead.

Christopher Capener
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