External phono preamp for Expert pro 140?

[thumb5]

Yes, typically Moving Coil uses a parallel resistor of about 100-200 Ohm to the coils. It is at the input of the pre-amp. If it is not fitted, the high freqency impulses overshoot.
Easiest is to solder a resistor into the phono plugs, parallel between the connectors.

The problem @Tanad has is that the impedance of the Devialet 140's phono stage is fixed at 47 ohms for MC, which is lower than the recommended 100 ohms. Adding another resistor in parallel across the input, as you suggested, will lower the input impedance still more (to about 32 ohms), so it is counter-productive.