While I very much respect Raul's and Atmasphere's comments on the subject, and I agree that the subject is a complex one . . . it isn't terribly ambiguous, and there are some simple facts to the subject.
First, transformers and inductors are eschewed components in undergraduate EE design practices, and this is for sound, logical reasons. But their potential shortcomings have been very well researched over many decades, and they can be measured . . . and it is indeed possible to transparently apply a high-quality transformer to the task of a MC input stage.
Second, since when is an audio transformer an 'economy' or 'low-budget' component? Yes, a designer can save some time and effort by slapping an off-the-shelf transformer in front of an existing MM phono stage and calling it done . . . but if the product is designed in this manner, the transformer's shortcomings are likely to be only the tip of the iceberg. This is a problem of methodology, not philosophy.
Third . . . in a low-noise circuit, input stage noise will dominate, if the designer has done his/her job correctly. And low-impedance transducers (like a low-output MC cartridge) simply do NOT deliver their best noise performance when coupled directly to an input stage, especially one that uses JFETs or vacuum tubes. Now I understand and respect a design approach that tolerates a mismatch here to acheive other objectives, but in terms of noise performance for i.e. a 5-ohm phono cartridge, a well-executed transformer/autoformer input topology will ALWAYS perform best.
And finally, the biggest issue with improper cartridge loading has very little to do with the transformer or the lack thereof, but with the lack of standards and consistency among cartridge manufacturers. There is simply too much variation in cartridge design and manufacturing methods to be able to allow EVERY cartrige to work its best with a single type of phono preamp . . . a simple gain adjustment and loading resistor can only do so much. Kinda like finding ONE amp that will bring out the absolute best from EVERY speaker.
First, transformers and inductors are eschewed components in undergraduate EE design practices, and this is for sound, logical reasons. But their potential shortcomings have been very well researched over many decades, and they can be measured . . . and it is indeed possible to transparently apply a high-quality transformer to the task of a MC input stage.
Second, since when is an audio transformer an 'economy' or 'low-budget' component? Yes, a designer can save some time and effort by slapping an off-the-shelf transformer in front of an existing MM phono stage and calling it done . . . but if the product is designed in this manner, the transformer's shortcomings are likely to be only the tip of the iceberg. This is a problem of methodology, not philosophy.
Third . . . in a low-noise circuit, input stage noise will dominate, if the designer has done his/her job correctly. And low-impedance transducers (like a low-output MC cartridge) simply do NOT deliver their best noise performance when coupled directly to an input stage, especially one that uses JFETs or vacuum tubes. Now I understand and respect a design approach that tolerates a mismatch here to acheive other objectives, but in terms of noise performance for i.e. a 5-ohm phono cartridge, a well-executed transformer/autoformer input topology will ALWAYS perform best.
And finally, the biggest issue with improper cartridge loading has very little to do with the transformer or the lack thereof, but with the lack of standards and consistency among cartridge manufacturers. There is simply too much variation in cartridge design and manufacturing methods to be able to allow EVERY cartrige to work its best with a single type of phono preamp . . . a simple gain adjustment and loading resistor can only do so much. Kinda like finding ONE amp that will bring out the absolute best from EVERY speaker.
