What constitutes a "high output" moving coil cart?

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

The "highest" of the "LOW output" moving coil cartridges have an output of about 0.7mV maximum -- that's seven tenths of a microvolt! Whereas the "lowest" of the "HIGH output" moving coil cartridges have, as noted above, a minimum of 2. mV AT LEAST; which is roughly three times that of the highest output of the low output (standard) moving coils.

And further, it should be noted that high output moving coil cartridges are really offered as a convenience for people who hope to obtain the 'magic' of a moving coil, but using the moving magnet input of a receiver or integrated amp. The problem is that high output moving coil cartridges really can't provide that 'magic' -- because in order to obtain a high output, they must have coils with many, MANY times the windings of 'regular' moving coils; and with such a heavy coil, their transient response is nothing like that of a 'real' low output moving coil.

In my opinion, there are many moving magnet and moving iron cartridges that out-class most of the high ouput moving coils (and some low output moving coils too!) and would be a much better (sonic) choice than a HOMC, if it's simply that a person just doesn't want to mess with (or pay for) an outboard MC phono amplifier or step-up transformer -- mandatory hardware if one wants to "do moving coil right", since most preamps or receivers only provide for MM cartridges, if they even have phonostages.
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High output means exactly that - high. That's, there is a lot of it, of the output.

Many thanks to all for the great responses. In particular:

"In my opinion, there are many moving magnet and moving iron cartridges that out-class most of the high ouput moving coils (and some low output moving coils too!) and would be a much better (sonic) choice than a HOMC..."

To me this is fascinating. Would you care to share any examples? Thanks again -

Robert

Nsgarch is exactly correct, unless you will be considering the multi-thousand $ MC's, there are many fine MM's that are worth considering. Some would argue that EVEN IF you will be considering top tier MC's, you should consider a MM. Read this and learn :-)

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1200430667&&&/Who-needs-a-MM-cartridge-type-when-we-ha

Another very important point to consider, which further supports the MM
route: In my experience, most preamps' MM section sound better (cleaner/simpler signal path) than their respective MC stage. Having said all that, if yours can accommodate (and you can afford) something like the Benz M2 MC, and you like/prefer the sound of a good MC, that is also a viable alternative. Good luck.