With no music playing, set your volume control to the highest position that you would normally set it at with the MM cartridges you have used. Then see how much higher you can turn it before the hiss level at the listening position becomes objectionable.
Let us know what those two settings are, in terms of clock-face positions (e.g., 12 o'clock, 3 o'clock etc). Assuming that the first of those two settings lies at or above the 12 o'clock position, if you can rotate the control perhaps 45 to 60 degrees or so higher before the hiss level becomes objectionable, and without running up against the top of the volume control's range, I suspect that you would be good to go, in terms of noise performance and gain, with any HOMC, down to perhaps 1 or 1.5 mv. If the first of those two settings lies significantly below the 12 o'clock position, a somewhat smaller amount of rotation would be equally good, as volume control adjustments become increasingly coarse at lower settings.
The smaller the difference between those two volume control positions, the closer you would want the HOMC's rated output level to be to the rated output levels of your MM's.
If you have access to a sound pressure level meter, all of this could be figured much more precisely.
Keep in mind, however, that there are issues of mechanical compatibility between cartridge and tonearm that have to be considered as well, particularly the relation between cartridge compliance and tonearm effective mass. Google those terms and you'll find lots of additional information.
Regards,
-- Al
Let us know what those two settings are, in terms of clock-face positions (e.g., 12 o'clock, 3 o'clock etc). Assuming that the first of those two settings lies at or above the 12 o'clock position, if you can rotate the control perhaps 45 to 60 degrees or so higher before the hiss level becomes objectionable, and without running up against the top of the volume control's range, I suspect that you would be good to go, in terms of noise performance and gain, with any HOMC, down to perhaps 1 or 1.5 mv. If the first of those two settings lies significantly below the 12 o'clock position, a somewhat smaller amount of rotation would be equally good, as volume control adjustments become increasingly coarse at lower settings.
The smaller the difference between those two volume control positions, the closer you would want the HOMC's rated output level to be to the rated output levels of your MM's.
If you have access to a sound pressure level meter, all of this could be figured much more precisely.
Keep in mind, however, that there are issues of mechanical compatibility between cartridge and tonearm that have to be considered as well, particularly the relation between cartridge compliance and tonearm effective mass. Google those terms and you'll find lots of additional information.
Regards,
-- Al