MC Output Voltage - Impact on Noise

If its 500-530 that is a reasonable default (not completely unloaded, but not too heavily loaded down either). The HP-200 that my friend had allowed for something like five different loading options, with the factory setting at 100k. Actually, we didn't even realize the unit allowed for different loading (who reads a manual?). It was only when the owner switched cartridges that we noted the noise problem and investigated by opening up the unit.

Noise is a particular concern in high efficiency horn systems. If you now have an issue with noise when phono is your source, you would have substantially less noise going to the Orpheus -- a signal that is 4 db further above an audible noise floor (assuming the phono chain is the source of noise) is a meaningful improvement.

I don't know if this applies to the Hovland HP-100, but, a friend's HP-200's built in phono stage seemed quite noisy (sounded like RFI noise). It turned out that the factory setting for loading was 100k ohms (essentially unloaded) and when this was changed, noise was substantially reduced. Some disassembly of the outer case was needed to access the switches that change the loading.