Gain for Moving Coil Cartridges

In a recent thread recommendations were solicited for possible MC cartridges for a Phono amp with 20db of gain. The cartridge I offered has an output of .4mV. Several replys indicated the two would not work very well because of insufficient gain. Is there any simple rule of thumb or explaination of the gain to output relationship?
With a 0.4 mV output cartridge, you'd need about three times the value you suggested. I have owned several cartridges with this gain value, and I've always found 60 dB a good match.

There is no simple rule-of-thumb. It really depends on your listening habits, but even more it depends on the gain structure of the linestage preamplifier into which you feed your phono preamplifier output.
For a moving coil cartridge with 0.4 mV of output, you probably need a phono preamp with about 60 db of gain (as already suggested). However, that depends a bit on whether you have a solid state or tube preamp. Generally speaking, a solid state unit with a bit less gain (say 50-55 db) may still work OK because it is usually quieter than a comparable tube preamp.
Sheesh, as soon as i read your question, 60 dB's of gain came to mind. I guess that great mind's think alike : ) Sean
Teamfunk, are you sure that you MM phono stage has only 20db of gain; 35-40db is more common in a MM stage.
60-65db at a .4mv cartridge