Phono stage and phono preamp

[THX2468]

Can someone briefly explain what phono stage mean and if I need a phono preamp please? I have the Sony DA5400ES with an amplifier Sony N9000ES at 200wtts per channel. Turntable is Sony PS-LX350H with an Audio Technica cartridge AT440MLa. I still feel that the sound is poor, if average volume on the receiver for other components is between -20db / -25db when I play a record I have to crank it up between -10db / 5db with low bass but high treble sound.
Thank you.

[Glen B]

A phono stage provides the proper RIAA equalization (see link below) and gain increase necessary to boost the tiny signal from the cartridge of only a few millivolts. Your receiver has such a phono stage built in. A phono preamp performs the same job, except that it is a standalone product to be used with receivers or preamps that lack a phono stage, or by persons who feel the phono stage in their existing equipment is lacking in some way.

The reason why you need to crank the volume control higher with vinyl playback is simply because phono just tends to have a lower output than other sources, especially CD, so you need to compensate by turning the volume control up. Keep in mind the volume control does not add signal, it only attenuates (cuts) the incoming signal. At its lowest setting the volume control is applying maximum attenuation.

The high treble you are experiencing may be indicative of improper loading of your phono cartridge. Loading of a moving magnet (MM) cartridge can directly affect frequency response. A load capacitance that is too low can result in excessive treble and weak bass and vice versa for too-high capacitance.

Look at the specifications for your cartridge for the recommended load capacitance (in picofarads or pf), the capacitance of the signal cables of your turntable, and the input capacitance if given, of the phono input of your receiver, and make a note of those numbers. When you total up the capacitance numbers of the signal cable and input of the receiver's phono input (together being the load) they should closely match the recommended load capacitance the cartridge requires. There should also be a recommended load resistance for the cartridge (usually 47K). Most receiver and preamp MM phono stages have a 47K input resistance.

For example, if the cartridge requires a load of 275pf and you have cables of 75pf and phono stage input capacitance of 100pf, that totals 175 pf -- you are short by 100pf. You could use cables with 175 pf of capacitance or very close to it, to bring the total load up to near 275pf. the figure does not have to be exact, just close.

RIAA Equalization Curve explained: http://en.wikipedia.org/wiki/RIAA_equalization

[THX2468]

Thank you very much for your detailed explanation.