121 mW into 33 Ω is 85 mA peak current, and 170 mA peak ground current with both channels driven. That is an unusually powerful cMoy, is it that NJM4556 one with no gain ? Typical cMoys use lower current op amps, and often even weaker virtual grounds (like the TLE2426 that cannot output much more than 30 mA). If it is some other cMoy and the crosstalk was measured with RMAA, note that RMAA lies about crosstalk and consistently shows it to be 6 dB better than reality, in addition to the measurement often being unreliable because of ground loops in a sound card loopback setup.
Those are numbers quoted from the Dark Lord NwQuestionableGuy's blah-spot site.
He did go all an about the allegedly mighty and apparently unloved NJM4556 indeed, and those numbers are apparently from a cMoy with that opamp installed. NwOpAmpGuy claims those numbers are w/o gain. The prufeshional genier dood does not seem to provide 33 ohm power numbers for the cMoy w gain (same NJM4566 amp), but it is supposed to give about the same juice to 150 ohms and a bit more into 15 ohms (all at the expense of distortion of course.) JDS Labs cMoy uses the OPA2227 instead so numbers are probably different with it.
As some of us know, NwdScopeGuy put RMAA on the spot, and may have compensated for it's issues... But He-who-seems-to-have-disappeared would know.
Edited by ultrabike - 2/25/13 at 11:07am