^^ That is a good question! It has to do with how the source (phono cartridge) is driving the load, which is to say that the source impedance should be lower than the load by about 10:1.
In the case of LOMC there does not seem to be a downside. LOMCs can drive low impedances with ease.
If we are talking line level, the equipment driving the cable should be able to drive a 600 ohm load. In the old days this was done with an output transformer (in the studio).
These days to do this you need a preamp that has some guts in the line section to drive such a load. Usually this results in a lower output impedance from that line section as well. Whether all this is a down side or trade-off is hard to tell; we solved the problem by doing a direct-coupled vacuum tube output and if anything it seems to sound better for it.
I think some might argue that the signal path is more complex when going balanced- twice as many parts is the old myth there (it does not take twice as many parts). I don't think the signal path has to be more complex; in our case we only have 3 stages of gain between the LOMC input and the output of the line section- I can't speak for all preamps here, but as far as I can tell you don't loose anything with the balanced line system.
Again, the amazing number of stereo LPs from the 1950s that are still sought for their excellent sound should tell you something.
In the case of LOMC there does not seem to be a downside. LOMCs can drive low impedances with ease.
If we are talking line level, the equipment driving the cable should be able to drive a 600 ohm load. In the old days this was done with an output transformer (in the studio).
These days to do this you need a preamp that has some guts in the line section to drive such a load. Usually this results in a lower output impedance from that line section as well. Whether all this is a down side or trade-off is hard to tell; we solved the problem by doing a direct-coupled vacuum tube output and if anything it seems to sound better for it.
I think some might argue that the signal path is more complex when going balanced- twice as many parts is the old myth there (it does not take twice as many parts). I don't think the signal path has to be more complex; in our case we only have 3 stages of gain between the LOMC input and the output of the line section- I can't speak for all preamps here, but as far as I can tell you don't loose anything with the balanced line system.
Again, the amazing number of stereo LPs from the 1950s that are still sought for their excellent sound should tell you something.