Ceramic elements - bend or twist? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

joebog1 · 6th Jul 2018, 10:59 am

I do remember as a kid I had a cheap multimeter known as the 200H
Superb, solid as a rock and 20,000 ohms per volt. ( is 10,000 OPV AC correct?? )
I could measure the output of a crystal cartridge!!
WITH EASE!!!

Its quite hopeless today, alas.

The articles I posted were a mere couple of pages of an American textbook, that contains many many many designs of different pickups, MOST of which I have never seen. I could scan and post the whole section if there is sufficient interest?

Joe

Radio Wrangler · 6th Jul 2018, 11:26 am

Velocity figures are quoted in terms of the velocity of the stylus tip with respect to the cartridge body.

If you have a silent period on a clean record, the stylus tip is travelling along the groove at high speed, but is not being deflected in any direction. So the velocity of the tip with respect to the cartridge is nil, the output voltage/voltages are nil and the record is silent. Change the turntable to any number of rpm and it stays silent.

If a fleck of muck in the speeding silent groove, knocks the stylus, it gets a bit of deflection velocity for a moment and a click is heard.

It is the velocity of motion in a plane perpendicular to the tangent of the groove at the point of contact which counts.

David

John10b · 6th Jul 2018, 12:03 pm

Thank you both, it does make it clearer to me now, could I ask you to look at my other thread, it will separate from this one which Suebutcher started.
Regarding scanning in other info,I’d be interested but not sure about others.
Cheers
John

Nickthedentist · 6th Jul 2018, 1:17 pm

Quote:

Originally Posted by suebutcher

Here's a TC8S exploded... I can draw up a TC8M if you want.

Amazing. Yes please!!

af024 · 6th Jul 2018, 2:05 pm

You know this is a question that I've been wondering about for some time. I particularly wondered how the two different plug-in Philips cartridges worked as one type seems to be a bend (the ceramic type) and the potentially other a twist.

I could see how the first type worked as the elements are arranged to bend to the 45 deg side walls of the record, but the crystal type (which uses the same plug-in body) was a mystery to me as the layers of crystal seem to be in the same plane (arranged horizontally). I could not (cannot) see how you could (can) end up with two distinct channels with no cross-talk with that arrangement. Witchcraft if you ask me!

All of this is of course is very relevant if you want to try and replace defective innards with various possible substitutes like the RS bi-morph piezo-electric element for instance (RS 285-784). Mind you, it looks like even that can come in various orientations looking at the data sheet!

https://www.vintage-radio.net/forum/...d.php?t=143851

Perhaps I was just lucky when I tried that as a possible repair route. Mind you, I think there' only one RS part number, so whatever that particular orientation is must be correct.

Regards,

Andy

John10b · 6th Jul 2018, 2:40 pm

I took a look at the rs piezo element and was interested to note the output is quoted as peak to peak. I have wondered if the output of cartridges was in rms or p to p as I noticed that some outputs are considerably higher than others, see Voice if Music for example.
Cheers
John

Synchrodyne · 8th Jul 2018, 12:07 am

I have added a comment about cartridge output voltages in your thread "Cartridge Specifications", https://www.vintage-radio.net/forum/...54#post1055654.

Cheers,

joebog1 · 8th Jul 2018, 2:14 am

***MODS***

As I offered in post 21, I have scanned what I believe is a very comprehensive article on Disc Recording .
Following the logic used in the book, I have started with the above subject, and if you are interested will continue with Cutting Heads, to be followed by Recording and Reproducing Stylii, and finally with Pickups. All these scans will be from the book pictured below.

This first offering is 46 pages long, with text scanned at 75 DPI, and photograhds scanned at 150 DPI, in an effort to keep the file smallish. I still ended up with a 5.5 meg PDF. If the mods are interested in seeing what I have done ( including one page upside down

) please email me for a copy, as I cant send it directly.

IF the mods are not interested, and somebody here is, likewise email me for a copy.

Regards
Joe

suebutcher · 8th Jul 2018, 7:43 am

Here's the TC8M exploded.

John10b · 8th Jul 2018, 8:08 am

Excellent thank you very much Suebutcher for your drawing all very interesting.
Thanks also to Syncrodyne for much information, lots to take in and try to fully understand.
Cheers
John

6th Jul 2018, 10:59 am	#21
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: Ceramic elements - bend or twist? I do remember as a kid I had a cheap multimeter known as the 200H Superb, solid as a rock and 20,000 ohms per volt. ( is 10,000 OPV AC correct?? ) I could measure the output of a crystal cartridge!! WITH EASE!!! Its quite hopeless today, alas. The articles I posted were a mere couple of pages of an American textbook, that contains many many many designs of different pickups, MOST of which I have never seen. I could scan and post the whole section if there is sufficient interest? Joe

6th Jul 2018, 11:26 am	#22
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,901	Re: Ceramic elements - bend or twist? Velocity figures are quoted in terms of the velocity of the stylus tip with respect to the cartridge body. If you have a silent period on a clean record, the stylus tip is travelling along the groove at high speed, but is not being deflected in any direction. So the velocity of the tip with respect to the cartridge is nil, the output voltage/voltages are nil and the record is silent. Change the turntable to any number of rpm and it stays silent. If a fleck of muck in the speeding silent groove, knocks the stylus, it gets a bit of deflection velocity for a moment and a click is heard. It is the velocity of motion in a plane perpendicular to the tangent of the groove at the point of contact which counts. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

6th Jul 2018, 12:03 pm	#23
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: Ceramic elements - bend or twist? Thank you both, it does make it clearer to me now, could I ask you to look at my other thread, it will separate from this one which Suebutcher started. Regarding scanning in other info,I’d be interested but not sure about others. Cheers John

6th Jul 2018, 2:05 pm	#25
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: Ceramic elements - bend or twist? You know this is a question that I've been wondering about for some time. I particularly wondered how the two different plug-in Philips cartridges worked as one type seems to be a bend (the ceramic type) and the potentially other a twist. I could see how the first type worked as the elements are arranged to bend to the 45 deg side walls of the record, but the crystal type (which uses the same plug-in body) was a mystery to me as the layers of crystal seem to be in the same plane (arranged horizontally). I could not (cannot) see how you could (can) end up with two distinct channels with no cross-talk with that arrangement. Witchcraft if you ask me! All of this is of course is very relevant if you want to try and replace defective innards with various possible substitutes like the RS bi-morph piezo-electric element for instance (RS 285-784). Mind you, it looks like even that can come in various orientations looking at the data sheet! https://www.vintage-radio.net/forum/...d.php?t=143851 Perhaps I was just lucky when I tried that as a possible repair route. Mind you, I think there' only one RS part number, so whatever that particular orientation is must be correct. Regards, Andy __________________ Now where on earth did I remove that from? Last edited by af024; 6th Jul 2018 at 2:06 pm. Reason: updated with RS part no.

6th Jul 2018, 2:40 pm	#26
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: Ceramic elements - bend or twist? I took a look at the rs piezo element and was interested to note the output is quoted as peak to peak. I have wondered if the output of cartridges was in rms or p to p as I noticed that some outputs are considerably higher than others, see Voice if Music for example. Cheers John

8th Jul 2018, 12:07 am	#27
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Ceramic elements - bend or twist? I have added a comment about cartridge output voltages in your thread "Cartridge Specifications", https://www.vintage-radio.net/forum/...54#post1055654. Cheers,

8th Jul 2018, 7:43 am	#29
suebutcher Heptode Join Date: Jul 2012 Location: Daylesford, Victoria, Australia Posts: 675	Re: Ceramic elements - bend or twist? Here's the TC8M exploded. Attached Thumbnails __________________ The Waves That Rule Britannia

8th Jul 2018, 8:08 am	#30
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,887	Re: Ceramic elements - bend or twist? Excellent thank you very much Suebutcher for your drawing all very interesting. Thanks also to Syncrodyne for much information, lots to take in and try to fully understand. Cheers John