Matching Your Cartridge To The Optimum Input; Mc1 And Mc2 Current Sensing Inputs; Mm/Mc1 And Mm/Mc2 Voltage Sensing Inputs - CH P10 User Manual

4 Matching your cartridge to the optimum input

Your P10 offers a choice of inputs and input types: inputs MC1 and MC2 operate in current mode.; inputs MM/
MC1 and MM/MC2 operate in the more common voltage mode. Each input can be individually configured to
match the connected cartridge. Each input type suits cartridges with different electrical characteristics.
Please note that each P10 input can be connected to either an RCA or an XLR terminated tonearm. XLR pin 2
and 3 are connected to the hot and cold leads of the cartridge's coil (internally connected to the RCA pin and
ring, respectively), while pin 1 is for shielding purposes (connected by default to analog ground in the P10).
Any unused P10 input(s) can be turned off. This will make input scrolling and selection easier, while reducing
power consumption as the unused input module will not be powered in this case. To turn off an input, please
refer to chapter 7.3 (input specific options).

4.1 MC1 and MC2 current sensing inputs

A current mode input reads the current generated by the cartridge (not its voltage). Current mode inputs are
usually dedicated to MC cartridges but also work well with the (very few) low-output MM cartridges available,
such as those from SoundSmith. The current from the cartridge is amplified by a discrete transistor based
trans-impedance amplifier. Using a current mode input provides a superior signal to noise ratio compared to
a conventional voltage input, better immunity and by its very nature, no requirement to adjust and optimize
impedance. The gain of the trans-impedance amplifier is intrinsically dependent on the internal impedance of
the cartridge. The lower the internal impedance of the cartridge, the higher the gain that results. For this reason,
your P10 provides multiple gain settings, adjustable in 3dB steps. Although a current mode input will work with
a cartridge whose internal impedance measures 50Ω, this is not an appropriate match. In general, the current
mode inputs will be ideal for cartridges with an internal impedance of below 10Ω. With a cartridge between 10Ω
and 20Ω internal impedance then you should compare performance between the current and voltage mode
inputs. Cartridges with an internal impedance above 20Ω will normally give their best performance with the
voltage mode inputs – but as always, experimentation is the order of the day.
In order to help users achieve the optimum gain value and signal to noise performance, CH Precision provides
the Gain Wizard, a process that measures the signal-to-noise performance of the system (cartridge and P10
input) in conjunction with the supplied 7" 45 RPM disc.

4.2 MM/MC1 and MM/MC2 voltage sensing inputs

A voltage mode input reads the voltage generated by the cartridge. The voltage mode inputs can be used with
any MM or MC cartridges, as well as with step-up transformers. The cartridge output signal is amplified by a
discrete, solid-state voltage amplifier. To accommodate the widest range of partnering cartridges and SUTs,
gain can be adjusted from +41 to +74dB (+6dB on balanced outputs) in 3dB steps. Each voltage mode input is
fitted with a user-variable resistive load (variable between 5Ω and 100 kΩ), allowing users to adjust cartridge
impedance loading to provide the optimum (flattest) frequency response, free of high frequency ringing.
In order to help users achieve the optimum impedance load value and gain for each input, in addition to
the Gain Wizard (detailed above) CH Precision provides the Loading Wizard, a process that measures the
frequency response of the system (cartridge, cables and P10 input) and displays the results of different
loading values as a series of graphs showing the flatness of the system.
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