When I play my vinyls.I have to turn the volume up higher on my receiver than when playing CD's. I get great volume with both, but was wondering if the above observation is normal or a sign of a problem? Thanks for your expertise.
Phono cartridges are similar to loudspeakers in that both are transducers. They convert one form of energy to another with no active circuits involved in the process. Therefore, a phono cartridge cannot have a "signal to noise ratio".
A phono cartridge outputs levels in the millivolts and requires a phono pre amp to raise that level sufficiently in order to adequately drive the power amplifier's input stage. Depending on the amount of voltage coming from the cartridge and the amount of gain applied in the phono pre amp, the final voltage sent to the power amp from a phono cartridge is still likely to be less than 1 volt peak. Most CD players typically output at least two volts R.M.S. and need no further gain stages. The difference in volume between a CD and a phono input comes down to the amount of voltage output by the device and the amount of gain applied to that voltage relative to the power amplifier's input sensitivity.