Hi system7,
I don't think balanced buys you anything at all when you are that close top the cartridge. Tone arm wire capacitance is reasonably low, and it is shielded really, really well.
For an MM cartridge, the capacitive load resonates with the cartridge to give a "flat" output response. You need the matching capacitance load for the cartridge. I hated people who installed low capacitance cables on turntables (unclear on the concept). I would measure the tonearm capacitance, lead wires and input capacitance to the phono [preamp and adjust it to agree with the cartridge manufacturer's recommended load.
Most tonearm wire is close, or at least it was in the 1970's and 1980's. Many cartridges wanted to see the same capacitance and phono preamp manufacturers installed enough to add to the average correct total value. But to get the best sound, you always checked. I used to use an HP 4261A until I got the 4263A LCR meters.
I don't think balanced buys you anything at all when you are that close top the cartridge. Tone arm wire capacitance is reasonably low, and it is shielded really, really well.
For an MM cartridge, the capacitive load resonates with the cartridge to give a "flat" output response. You need the matching capacitance load for the cartridge. I hated people who installed low capacitance cables on turntables (unclear on the concept). I would measure the tonearm capacitance, lead wires and input capacitance to the phono [preamp and adjust it to agree with the cartridge manufacturer's recommended load.
Most tonearm wire is close, or at least it was in the 1970's and 1980's. Many cartridges wanted to see the same capacitance and phono preamp manufacturers installed enough to add to the average correct total value. But to get the best sound, you always checked. I used to use an HP 4261A until I got the 4263A LCR meters.
I wanted to sleep on remarks about record playing transducers....and it's a bit off-topic, I suppose. But you are right that balanced may be overkill when connected to a pickup with no horrible 100 ohm RCA phono lead, with built in capacitance with a 47k load.
MY PLAN was to give a MM a purely resistive load, which is what a MC gets at the end of the day. No cable capacitance and maybe avoid inductance and its inevitable high frequency rolloff.
But it didn't work so well. I tried between 5k and 100k loads with MM cartridges. My conclusion was that MC is a better way to do things. Because a coil is lighter than a magnet or ferrite as the moving part!
And a load of 100 ohms matches an RCA phono better.
This goes for tweeters as well if you think about it. It would be a disaster to connect the cone to the magnet assembly, rather than the coil. It's simply too heavy.
I don't think exploiting a LC resonance is a good idea with a pickup either. It must make the stylus tip resonate and mistrack in the highly non-linear groove unless huge tracking force is applied.
The BBC used tracking weights we would consider outrageous, up to 70 grams:
https://www.orbem.co.uk/grams/grams_8.htm
Built like a tank! 70kg weight turntables in the studio. Very interesting if you like to see what "cost no object" looked like. XLR connectors too, to avoid hum and RF pickup.
I am happy enough with CD quality, and I suppose people like Rotel never drop their standards too much, though the purist might internet 24 bit streams like Deutsche Grammaphon these days.
Mustn't go on. Vinyl playback can be very good indeed, and was good even back in the day. But was always a rich persons hobby if you wanted real quality.
MY PLAN was to give a MM a purely resistive load, which is what a MC gets at the end of the day. No cable capacitance and maybe avoid inductance and its inevitable high frequency rolloff.
But it didn't work so well. I tried between 5k and 100k loads with MM cartridges. My conclusion was that MC is a better way to do things. Because a coil is lighter than a magnet or ferrite as the moving part!
And a load of 100 ohms matches an RCA phono better.
This goes for tweeters as well if you think about it. It would be a disaster to connect the cone to the magnet assembly, rather than the coil. It's simply too heavy.
I don't think exploiting a LC resonance is a good idea with a pickup either. It must make the stylus tip resonate and mistrack in the highly non-linear groove unless huge tracking force is applied.
The BBC used tracking weights we would consider outrageous, up to 70 grams:
https://www.orbem.co.uk/grams/grams_8.htm
Built like a tank! 70kg weight turntables in the studio. Very interesting if you like to see what "cost no object" looked like. XLR connectors too, to avoid hum and RF pickup.
I am happy enough with CD quality, and I suppose people like Rotel never drop their standards too much, though the purist might internet 24 bit streams like Deutsche Grammaphon these days.
Mustn't go on. Vinyl playback can be very good indeed, and was good even back in the day. But was always a rich persons hobby if you wanted real quality.
Nick Sukhov has been advocating high resistive loads for moving-magnet cartridges for years. He claims that most modern low-effective-mass cartridges work well with a 150 kohm load, capacitance kept as small as possible by building the phono preamplifier into the turntable.
Even back in 1980 there were much better opamps from Harris using an early implanted process, that allowed excellent PNP transistors. All in metal can and they were expensive.
Here is some history about NE5532 and more
https://en.wikipedia.org/wiki/NE5532
NE5532 was introduced 1979
https://en.wikipedia.org/wiki/NE5532
NE5532 was introduced 1979
Hi system7,
Read from various manufacturers on their MM Cartridges. The capacitance is required to resonate. Alternative loadings may work with some cartridges.
Also, read up on the Ortofon old VMS principle where both magnet and coil were stationary. Yes, they used an iron vane, lighter than a magnet.
MC means you have around 20 dB S/N ratio hit, or more depending on output level. We can argue the surface noise is higher I guess. Absolutely, very good quality record performance is an expensive game, but not out of sight.
Read from various manufacturers on their MM Cartridges. The capacitance is required to resonate. Alternative loadings may work with some cartridges.
Also, read up on the Ortofon old VMS principle where both magnet and coil were stationary. Yes, they used an iron vane, lighter than a magnet.
MC means you have around 20 dB S/N ratio hit, or more depending on output level. We can argue the surface noise is higher I guess. Absolutely, very good quality record performance is an expensive game, but not out of sight.
I don't think the signal-to-thermal-noise ratio at the output of a moving-coil cartridge is worse than at the output of a moving-magnet cartridge. The signal voltage is some 20 dB smaller, but the thermal noise voltage of a moving-coil cartridge is a lot less than that of a moving-magnet cartridge.
You will just need to design the phono preamplifier differently. To get back on topic, an NE5532 would not be particularly suitable for moving coil.
You will just need to design the phono preamplifier differently. To get back on topic, an NE5532 would not be particularly suitable for moving coil.
Offtopic :
regds.
It was discussed in the forum in the past. For theoretically frictionless bearing the weight would not be a problem (inertia). So if high quality extremely low friction bearings are used It would have worked.
regds.
Hi Marcel,
It's the extra gain in the circuit required and noise from that circuit that is a concern. No the cartridge. The practical realization on the phono amplifier.
That, and I'm sorry. If I need a new stylus, I am not shipping the entire thing off and waiting - assuming nothing happens to the cartridge in the round trip. The other alternative is to buy another cartridge and bounce back and forth between them.
It's the extra gain in the circuit required and noise from that circuit that is a concern. No the cartridge. The practical realization on the phono amplifier.
That, and I'm sorry. If I need a new stylus, I am not shipping the entire thing off and waiting - assuming nothing happens to the cartridge in the round trip. The other alternative is to buy another cartridge and bounce back and forth between them.
Thanks for the clarification. I still disagree, though.
Due to the huge source inductance, the equivalent input noise current of the preamplifier has a much greater impact in the moving-magnet case than in the moving-coil case. If the 47 kohm input termination is made by simply soldering a 47 kohm resistor across the input, that alone causes 0.5869 pA/√Hz of noise current to be injected into the source. For a typical 500 mH moving-magnet cartridge, that has about as much effect on the RIAA- and A-weighted noise as a 7 nV/√Hz equivalent input noise voltage.
For moving coil, the noise current does almost nothing, but equivalent input noise voltage is about 10 times as important as for moving magnet due to the about 10 times smaller signal voltage. When noise current doesn't matter much, you can realize a 0.7 nV/√Hz equivalent input noise voltage by using a bipolar transistor with a low base resistance biased at a couple of milliamperes of collector current and a very-low-impedance feedback network.
All in all, assuming competently designed preamplifiers, I don't see why there would be huge differences in signal-to-cartridge-thermal-noise-plus-preamplifier-noise ratio.
The new stylus issue is a different matter altogether. I agree that moving magnet is more convenient in that sense.
Due to the huge source inductance, the equivalent input noise current of the preamplifier has a much greater impact in the moving-magnet case than in the moving-coil case. If the 47 kohm input termination is made by simply soldering a 47 kohm resistor across the input, that alone causes 0.5869 pA/√Hz of noise current to be injected into the source. For a typical 500 mH moving-magnet cartridge, that has about as much effect on the RIAA- and A-weighted noise as a 7 nV/√Hz equivalent input noise voltage.
For moving coil, the noise current does almost nothing, but equivalent input noise voltage is about 10 times as important as for moving magnet due to the about 10 times smaller signal voltage. When noise current doesn't matter much, you can realize a 0.7 nV/√Hz equivalent input noise voltage by using a bipolar transistor with a low base resistance biased at a couple of milliamperes of collector current and a very-low-impedance feedback network.
All in all, assuming competently designed preamplifiers, I don't see why there would be huge differences in signal-to-cartridge-thermal-noise-plus-preamplifier-noise ratio.
The new stylus issue is a different matter altogether. I agree that moving magnet is more convenient in that sense.
I guess that is why vinyl sounds better in Nunavut, Canada versus the poor sound quality you get in the Falkland Islands.
If anything, MC signal output POWER is higher than most MM. Just that it's much harder to make a low NF amplifier at such low impedances and SUTs have their own problems, including significant thermal noise due to winding resistance.