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10 Phono-input optimization
Before connecting your turntable(s), arm(s) and cartridge(s) to the P10, it is worth establishing a few initial
performance/electrical parameters. These can normally be found in the specifications supplied by the
cartridge manufacturer and if no Specification sheet is available, can usually be discovered online, either at the
manufacturer's website or on one of the various analog data bases.
The key value that you are looking for is the internal impedance of the cartridge.
If this is in the range 0-5Ω then the cartridge will almost certainly work best into a current mode input,
(MC1 or 2).
If this is in the range 5-10 Ω then the cartridge will most probably work best into a current mode input,
(MC1 or 2).
If this is in the range 10-20Ω then the cartridge may well still work best into a current mode input, but it is
worth comparing performance between the current and voltage mode inputs.
If this is above 20Ω then the cartridge will probably work best into a voltage mode input, (MM/MC1 or 2).
If you are using an external step-up transformer (SUT) this should be connected to one of the voltage mode
inputs (MM/MC1 or 2).
If you are using a high-output MC or MM cartridge (output >2.0mV) this should be connected to one of the
voltage mode inputs (MM/MC1 or 2).
10.1 Getting the best performance from the current-sensing inputs
If you choose to connect your cartridge to a current-sensing input, the only adjustment that you will need to
make is to set the gain. This can be set between +12 and +33dB, in 3dB steps, so extremely fine tuning is possible
and worthwhile. You can establish the optimum signal to noise setting using the Gain Wizard, or you can simply
listen to the result, but either way, the final choice should be made by listening to your preferred music.
If, like the CH Precision L10 or L1, your line-stage pre-amplifier has variable input sensitivity, it is worth
experimenting with the gain structure between the phono-stage and the line-stage.
10.2 Getting the best performance from the voltage-sensing inputs
If your cartridge is better suited to the voltage-sensing inputs of the P10, then you will need to adjust both the
gain and impedance loading values. You should start by setting the impedance loading, as this affects the output
level of the cartridge. Manufacturers will often recommend a loading range for their cartridges, but this is often
too wide to be useful. We would suggest the following approach:
Set the impedance load to a median value in the range recommended by the cartridge manufacturer. Don't
worry – this value may well change, in some cases considerably.
Having set the initial value for impedance loading, you can now set the gain (+42dB to +75dB), either by ear
or using the Gain Wizard to achieve an initial setting. Final gain should be set by listening to your preferred
music.
Use the Loading Wizard (following the instructions below) to refine the loading value for the flattest
frequency response. Loading the cartridge down has the affect of controlling the characteristic rising high-
frequency output you find in all cartridges, so establishing the best value is important to also delivering the
best balance of high frequency extension/energy and frequency balance.
P10 User Manual
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