As per one of the senior designers at Audio Technica, the ART7 aimed for classical music. It is a little more transparent and micro-detailed than ART9 but the ART9 sounds bigger, more powerful with realistic bass which works very well for Jazz, Rock, Blues and Pop.
In any case the ART7 needs a matching step-up transformer to get the right gain. No active phonostage (in my knowledge) will do justice to 0.1mv (even if the specs might suggest otherwise). These very low output carts are designed with SUTs in mind. Take for example the Benz Ebony TR. It is the best Benz cartridge (better than LP-S) but it is not easy to amplify satisfactorily. IMO, the ART9 is a much more rational everyday cartridge which is not below the ART7.
In any case the ART7 needs a matching step-up transformer to get the right gain. No active phonostage (in my knowledge) will do justice to 0.1mv (even if the specs might suggest otherwise). These very low output carts are designed with SUTs in mind. Take for example the Benz Ebony TR. It is the best Benz cartridge (better than LP-S) but it is not easy to amplify satisfactorily. IMO, the ART9 is a much more rational everyday cartridge which is not below the ART7.