hifi engine

Signal to noise ratio

What's the difference between a signal to noise ratio expressed as MM vs line? Such as 80 dB MM, 100 dB line for the same unit.



Re: Signal to noise ratio

It is not a difference of expression as such. "80 dB MM" is the quoted signal to noise ratio of the amplifier's Moving magnet (MM) phono input stage. "100 dB line" is the quoted signal to noise ratio of the amplifier's line inputs (i.e tuner, c.d , tape, etc). The signal to noise ratio of the phono input is naturally smaller because of the additional amplification required and considerably smaller with MC (moving coil) phono inputs.

Re: Signal to noise ratio

Thanks. That makes sense. Hifiengine is the only place I've seen this. Is it fair to assume that when you see only one listed, without the MM or Line designation, that it is the higher Line type? Is one more important than the other?
Thanks again.

Re: Signal to noise ratio

There are a number of reasons why the "MM" signal to noise ratio figure is not always quoted for a given amplifier. The amplifier may not have a "MM" input, or the manufacturer has not disclosed the figure, maybe because the spec is so awful ! I would say that the "MM" spec is more significant, for if that spec is good, then it follows that the line inputs' specs will very likely be too. Anyway, I wouldn't get too "hung-up" on spec sheets, as manufacturers have been known to be less than accurate with their kit's performance figures ! Spec sheets should be approached with caution and certainly not taken at face value. Used as a guide is fine, but let the ears have the final say !

Re: Signal to noise ratio

Thanks for the information. You've been very helpful.

Tom DeRosear
Cheyenne, WY

Re: Signal to noise ratio

You're welcome.