While I’m sure that the VAC and the Luxman are both wonderful preamps, in the case of the VAC I would find it a little off-putting that loading of LOMC cartridges cannot be set higher than 470 ohms. And while I couldn’t find relevant specs on the Luxman, I wouldn’t be surprised if it is similar in that respect, given that both designs apparently use step-up transformers at their LOMC inputs.
The 20 db gain difference between the VAC’s LOMC and MM inputs corresponds to an impedance transformation of 100x, given that a SUT is providing that gain. The 47K maximum input impedance of the MM section divided by 100 is 470 ohms.
Like some of the others, I am a very happy owner of the Herron phono stage. Its LOMC input stage is FET-based, and Keith Herron recommends (as I have found) that no loading (i.e., the nearly infinite input impedance it presents when external loading plugs are not applied) is often preferable with it. And in this thread Lyra cartridge designer Jonathan Carr has explained that less resistive loading (i.e., higher load impedance) can "benefit dynamic range, resolution and transient impact."
Good luck, however you decide to proceed. Regards,
-- Al
The 20 db gain difference between the VAC’s LOMC and MM inputs corresponds to an impedance transformation of 100x, given that a SUT is providing that gain. The 47K maximum input impedance of the MM section divided by 100 is 470 ohms.
Like some of the others, I am a very happy owner of the Herron phono stage. Its LOMC input stage is FET-based, and Keith Herron recommends (as I have found) that no loading (i.e., the nearly infinite input impedance it presents when external loading plugs are not applied) is often preferable with it. And in this thread Lyra cartridge designer Jonathan Carr has explained that less resistive loading (i.e., higher load impedance) can "benefit dynamic range, resolution and transient impact."
Good luck, however you decide to proceed. Regards,
-- Al