Cartridge output 1.0mv to 65db gain phono, problem?


Hi,
I am using the Zyx Omega which has output of 0.24mv (3.54cm/sec) with the Zyx Artisan mc at 60db of gain. My mcintosh c2200 volume at half way. Now I am thinking of purchase the Zyx mono with the output of 1mv(5cm/sec). Does my phono have too much gain for the mono cartridge?
Thanks,
Calvin

dangcaonguyen
I have used a 1mv (.9mv measured) cart with my 57.5 dB gain phono pre.  The result was ok for mid to high level listening.  The software of the digital gain control induced a gain curve at the lowest volume settings, as does your preamp, that increases the gain between steps to mimic an analog volume pot.  I could not adequately control the volume level - it was either too loud or too soft.  My pre has 120 steps while yours has 214.  That may or may not be enough help.  

First, for the benefit of others who may contribute to the thread I’ll mention that the 65 db number in the title should apparently be 60 db.

1.0 mv is about 8 db less than 2.5 mv, and about 12 db more than 0.24 mv. Given that you have operated the volume control around its mid-point using a 2.5 mv cartridge with the phono stage in MM mode and also using a 0.24 mv cartridge with the phono stage in MC mode, I suspect that with the 1.0 mv cartridge you would be setting the volume control to roughly around 75% in MM mode and around 25% in MC mode.

Keep in mind, though, that your preamp provides an input trim function which may be helpful. It has a specified range of +/- 6 db.

A quick experiment that may be useful would be to set the phono stage to MM mode, and with no music playing turn the volume control up to 75%, or somewhat more, and see if noise levels remain acceptable.

Regarding MC mode, unfortunately specs or measurements that would indicate the overload point of the phono stage don’t seem to be available. FWIW my guess is that you would be ok in that respect, but 60 db would boost a 1 mv signal to 1 volt, and high volume dynamic peaks on some recordings presumably could result in the cartridge putting out several times more than 1 mv. Which could very well be fine, but without further information doesn’t seem entirely comfortable with respect to the possibility of overloading the phono stage. And also with respect to the fact that the line stage of your preamp has relatively high gain (about 15 db, if the input trim control is at its default setting of 0). You might ask Mehran at SORAsound if he can give you some idea of how much voltage would overload the phono stage in MC mode.

Finally, I’ll mention that the difference between the 5 cm/sec and 3.54 cm/sec numbers you mentioned is 3 db. Although depending on how those numbers are defined, there **may** be no actual difference between them. See the posts dated 7-4-2012 in this thread.

Hope that helps. Regards,
-- Al

I used the MM for the 2.5 mv HOMC and i had to turn up the volume to 53%. I dont know about 1mv now. 
The Artisan that I owned (great phonostage for sure) had an MM and an MC input.  Just use the lower gain MM input and you should be fine.