Ceramic cartridge to line level input circuit

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#23
1. If you want any bass from a ceramic cartridge (or any piezo transducer), a 1meg ohm input impedance is minimal. 2.2 meg Ohms or higher is recommended. They do not require RIAA eq when used with a hi-impedance input such as was typical of very simple vacuum tube record players.
2. Instrument amplifiers like ina217 are too slow for audio and the DC precision is useless.
3. For this purpose, a FET input op-amp is the best choice, with gain minimal or none. Years ago, I had a Phillips cassette recorder where the line inputs were a 2.2Meg resistor to the (unbalanced) microphone input, and that worked well with ceramic cartridges.
 
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#24
steveu said:
1. If you want any bass from a ceramic cartridge, a 1meg ohm input impedance is minimal. 2.2 meg Ohms or higher is recommended. They do not require RIAA eq when used with a hi-impedance input such as was typical of very simple vacuum tube record players.
2. Instrument amplifiers like ina217 are too slow for audio and the DC precision is useless.
3. For this purpose, a FET input op-amp is the best choice, with gain minimal or none. Years ago, I had a Phillips cassette recorder where the line inputs were a 2.2Meg resistor to the (unbalanced) microphone input, and that worked well with ceramic cartridges.
Click to expand...
That is excellent information. All I need is a circuit diagram. Is it possible that you can provide this for me? Thanks
 
#25
I would reverse the question: do you insist on this cartridge? It will sooner or later ruin your LPs. You could buy a modern MM (moving magnet) cartridge for $55. Unless it is the 78rpm version, but there are alternatives for it, too.
 
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#26
Ok, so this is a high impedance buffer for two channels. I used TL082 because it's in the LTC library but TL072 is probably better choice. Note that this shows two single op-amps, but TL072/82 are a dual where both share the supply pins. I show feedback for 10dB gain but you may want to adjust that for whatever gain works with your system. Gain = 20log((R8+R5)/R5) and 20log((R7+R6)/R6). A 9V battery is probably enough but you may want two, ie 18V.

I agree with Icsaszar about wearing out your vinyl with a ceramic cartridge.
 

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#27
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#28
lcsaszar said:
I would reverse the question: do you insist on this cartridge? It will sooner or later ruin your LPs. You could buy a modern MM (moving magnet) cartridge for $55. Unless it is the 78rpm version, but there are alternatives for it, too.
Click to expand...
This the cartridge that is used on my 1946 Rock-ola jukebox. It plays 78 RPM shellac records and tracks at 8 grams.
 

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#29
steveu said:
Ok, so this is a high impedance buffer for two channels. I used TL082 because it's in the LTC library but TL072 is probably better choice. Note that this shows two single op-amps, but TL072/82 are a dual where both share the supply pins. I show feedback for 10dB gain but you may want to adjust that for whatever gain works with your system. Gain = 20log((R8+R5)/R5) and 20log((R7+R6)/R6). A 9V battery is probably enough but you may want two, ie 18V.

I agree with Icsaszar about wearing out your vinyl with a ceramic cartridge.
Click to expand...
Steveu,
Excellent! I really appreciate your efforts on this. Would you be willing to share the LTspice asc file?
This ceramic cartridge will be used on 78 rpm shellac records not vinyl. Shellac is much harder than vinyl.
Thanks again
Scott
 
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#31
@rayma thanks, that would be the one 🙂

Time plays tricks, I was to young back then (in single figures 😀) to be taking WW so I must have seen it many years later in a large hardback book of wireless world audio projects that a local library had. It brings back memories.
 
#32
jsthomps said:
This the cartridge that is used on my 1946 Rock-ola jukebox. It plays 78 RPM shellac records and tracks at 8 grams.
Click to expand...
I see. My family had a Garrard record changer when I was young. It had a ceramic cartridge with sapphire stylus. There were two styli on the cantilever, and it could be turned over to play 78s.
I was keen on experimenting, and I read somewhere the following trick: load the cartridge with 1k resistor. That converted the piezo crystal to a current output device (the current on the resistor was roughly proportional to groove velocity), so it could be directly connected to a phono input having RIAA equalization. It worked well, as far as I remember.
 
#39
A generic no name amp?
Or a shop purchased item with a brand name and model number?
Do it yourself amp?
How much output?
Or a generic pre amp circuit? As an all in one level matching device?

Female or not, you are being mysterious and confused.
And ceramic cartridges went out of fashion long back.
Also, their output at times is enough for some amps. No need for a pre amp.
 
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