Most moving magnet cartridges have a recommended load capacitance range specified by the manufacturer. For the AT150MLX the recommended range is 100 to 200 pf (picofarads), as can be seen here.
That figure represents the total load capacitance seen by the cartridge, which is the sum of the capacitances of all of the wiring between the cartridge and the input of the phono stage, plus the input capacitance of the phono stage.
If the amount of capacitive loading of a moving magnet cartridge is either too high or too low, frequency response flatness in the upper treble region, or possibly even in the lower treble and upper mid-range, may be adversely affected.
Phono cable capacitance is proportional to length, and is also highly dependent on the particular cable type. It may or may not be specified by the cable manufacturer. If it is specified, it would be specified in terms of pf per unit length (for example, pf/foot).
100 and 200 pf are relatively low values, and for typical setups the concern is more likely to be keeping the total capacitance low enough to be in that range, rather than having to increase it. So unless your phono cables are particularly short (for example, 3 feet or less) and are also of a type that has particularly low capacitance (for example, 15 pf per foot or less), I suspect that chances are you will get best results by adjusting the phono stage's load capacitance setting to its minimum possible value.
Ideally, though, you should try several different values, and it is certainly possible that the value which will sound best in your system, to you, will be different than what the OP found was best in his system, for him.
Regards,
-- Al
That figure represents the total load capacitance seen by the cartridge, which is the sum of the capacitances of all of the wiring between the cartridge and the input of the phono stage, plus the input capacitance of the phono stage.
If the amount of capacitive loading of a moving magnet cartridge is either too high or too low, frequency response flatness in the upper treble region, or possibly even in the lower treble and upper mid-range, may be adversely affected.
Phono cable capacitance is proportional to length, and is also highly dependent on the particular cable type. It may or may not be specified by the cable manufacturer. If it is specified, it would be specified in terms of pf per unit length (for example, pf/foot).
100 and 200 pf are relatively low values, and for typical setups the concern is more likely to be keeping the total capacitance low enough to be in that range, rather than having to increase it. So unless your phono cables are particularly short (for example, 3 feet or less) and are also of a type that has particularly low capacitance (for example, 15 pf per foot or less), I suspect that chances are you will get best results by adjusting the phono stage's load capacitance setting to its minimum possible value.
Ideally, though, you should try several different values, and it is certainly possible that the value which will sound best in your system, to you, will be different than what the OP found was best in his system, for him.
Regards,
-- Al