CU = Compliance Units
Every cartridge has a suspension which surrounds the cantilever and dampens its movements, much like the suspension of a car. Just as with cars, there are soft suspensions and firm ones.
High compliance (high CU) cartridges have soft suspsensions. They are best suited for low mass tonearms like hubby's JMW-9.
Low compliance (low CU) cartridges like the Denon 103 have firmer suspensions. They are best suited for a higher mass tonearm, which hubby apparently doesn't own.
100 ohms
A cartridge is an electrical generator. Moving coil cartridges (MC's) like the 103 work by waving a coil of wire around inside a magnetic field to generate AC. Now the electrical resistance of a ciruit acts as impedance to the flow of AC. Impedance is frequency dependent, so the higher the impedance of the circuit the more freely high frequencies will flow. If the impedance of the phono circuit is higher than what the cartridge was designed for, the cartridge will sound hard, bright and grainy.
An MC is also like a motor, which works by running AC through a coil inside a magnetic field, causing the motor to move. Impedance on the circuit dampens the amount of motion the motor is free to produce. High impedance values provide little damping, low impedance values provide much damping. Again, if the impedance of the circuit is higher than what the cartridge was designed for, the cartridge will be underdamped and sound hard, bright or grainy.
HUBBY
Is just learning about the differences between the inexpensive moving magnet cartridges we all grew up with and today's higher performing moving coils.
Compliance wasn't often an issue with those MM's. Most of them were fairly similar (high) in compliance and the arms designed for them were suitably low in mass. Mismatches were rare. Such is not the case with MC's. Compliance of MC's ranges from a low 5cu to 25cu or higher. Cartridge-arm matching is critical to get the kind of performance we expect from these expensive toys. High end analog reproduction is definitely not plug-and-play.
Impedance was never an issue with hubby's MM's either. All MM's are designed to operate into the same impedance, 47K ohms. Unfortunately, there is no such standard for MC's. Each brand and sometimes each model is different. We either have to adjust the impedance of our phono circuit to suit the MC or choose an MC designed for the impedance of our phono circuit. No MC will perform properly if there's an impedance mis-match.
Yikes! There's no way around these issues except to do your homework. Fewer and fewer dealers have any knowledge in these areas, they just want to sell HDTVs and surround systems. Since you're now the resident expert in analog reproduction, I'd suggest you kick back, request a glass of wine and gently let him explain that there's more to this than you knew. ;-)
Every cartridge has a suspension which surrounds the cantilever and dampens its movements, much like the suspension of a car. Just as with cars, there are soft suspensions and firm ones.
High compliance (high CU) cartridges have soft suspsensions. They are best suited for low mass tonearms like hubby's JMW-9.
Low compliance (low CU) cartridges like the Denon 103 have firmer suspensions. They are best suited for a higher mass tonearm, which hubby apparently doesn't own.
100 ohms
A cartridge is an electrical generator. Moving coil cartridges (MC's) like the 103 work by waving a coil of wire around inside a magnetic field to generate AC. Now the electrical resistance of a ciruit acts as impedance to the flow of AC. Impedance is frequency dependent, so the higher the impedance of the circuit the more freely high frequencies will flow. If the impedance of the phono circuit is higher than what the cartridge was designed for, the cartridge will sound hard, bright and grainy.
An MC is also like a motor, which works by running AC through a coil inside a magnetic field, causing the motor to move. Impedance on the circuit dampens the amount of motion the motor is free to produce. High impedance values provide little damping, low impedance values provide much damping. Again, if the impedance of the circuit is higher than what the cartridge was designed for, the cartridge will be underdamped and sound hard, bright or grainy.
HUBBY
Is just learning about the differences between the inexpensive moving magnet cartridges we all grew up with and today's higher performing moving coils.
Compliance wasn't often an issue with those MM's. Most of them were fairly similar (high) in compliance and the arms designed for them were suitably low in mass. Mismatches were rare. Such is not the case with MC's. Compliance of MC's ranges from a low 5cu to 25cu or higher. Cartridge-arm matching is critical to get the kind of performance we expect from these expensive toys. High end analog reproduction is definitely not plug-and-play.
Impedance was never an issue with hubby's MM's either. All MM's are designed to operate into the same impedance, 47K ohms. Unfortunately, there is no such standard for MC's. Each brand and sometimes each model is different. We either have to adjust the impedance of our phono circuit to suit the MC or choose an MC designed for the impedance of our phono circuit. No MC will perform properly if there's an impedance mis-match.
Yikes! There's no way around these issues except to do your homework. Fewer and fewer dealers have any knowledge in these areas, they just want to sell HDTVs and surround systems. Since you're now the resident expert in analog reproduction, I'd suggest you kick back, request a glass of wine and gently let him explain that there's more to this than you knew. ;-)