How much gain is needed in a Phono Preamp for a 0.2 to 0.3mv low output moving coil?

As usual Larryi makes an excellent point, in this case about the relevance of line stage gain and amplifier sensitivity. I see in one of the OP’s recent posts that he has recently purchased an ARC REF 5SE line stage (12 db gain for its balanced outputs) and a REF 75 amplifier (1.4 volt sensitivity).

Based on the relation...

db = 20 x logarithm(Vout/Vin)

it can be calculated that 60 db of gain corresponds to a voltage multiplication of 1000 times, and 12 db of gain corresponds to a voltage multiplication of about 4 times. Therefore 0.2 mv into a 60 db phono stage and a 12 db line stage will provide an input to the amplifier of 0.2 mv x 1000 x 4 = 0.8 volts, ***when the volume control on the line stage is turned up all the way.***

Since the amp requires 1.4 volts to be driven to full power, with a 0.2 mv cartridge and a 60 db phono stage you would therefore only be able to drive the amp to full power on particularly high volume peaks that are present on some recordings, that exceed the standard test conditions upon which cartridge output ratings are based. And even then you would find yourself turning the volume control up to close to the top of its range, especially on recordings having wide dynamic range. With excessive hiss possibly also resulting.

FWIW, I use a 0.5 mv cartridge (the Audio Technica AT-ART9) with a 64 db phono stage (the Herron VTPH-2, which is also offered in a 69 db version BTW), in a system having particularly high gains and sensitivities further downstream, and that works out well.

Finally, I suggest caution in using the KAB calculator. Note the following statement in the text above the calculator:

The optimum gain is based on achieving 325mV rms output at 5 cm/s. For the current crop of CD recorders, 300mV is required for 0dB recording level with the recorder’s level control set at max. Aiming for 325mV gives a little margin.

325 mv multiplied by the 4x gain of your line stage would result in 1.3 volts into your power amp when the volume control is at max, which would still not be enough to drive the amp to full power.

Good luck. Regards,
-- Al

Lots of good comments, many of them cautiously worded...I hope your takeaway is that you could do better.
I have recently troubleshooted a friend's Chinook/Prime setup and before we got things sorted out had to get replacement tubes for the Manley and properly functioning junction box from VPI. Even after working through that, with his Ortofon Qunitet Black(0.3mv) his Primaluna linestage needed to be cranked up very high and while generally musical, I wouldn't call it a quiet presentation, nor one that I could live with. IMHO, 60db gain in the phono stage would be better matched with a cart >=.5mv. There are plenty of nice phono stages that offer 65 or 70db gain. When dealing with small phono signals an extra 5db of quiet gain is nothing to sneeze at.
Contrary to some here, I would suggest staying away from adding a SUT at this level of system, as most of them will take away from the purity of the signal, add more cabling and related susceptibility to incremental RFI/EMI. When considering adding a Kondo SUT to your 6figure table setup, then maybe you can convince me otherwise. Cheers,
Spencer

"Thank You" everyone for the help. I have been away from this so long I will probably never catch up. I am constantly learning things and finding new products. I had looked at the Herron and the ARC Ref. but the price set me back a little. I had never heard of the Orpheus (Transfiguration) cartridge and had to check it out. I like everything I read about the Benz (lowest $1800) and after reading about the Transfiguration cartridges (lowest $2450) I was very impressed. That being said, I am very concerned that with the VPI Prime I may be spending more on a cartridge than I should considering my TT. Please honest opinions, you will not hurt my feelings.Opinions help you learn.
Not sure if anyone tried this. I went to the store that sells Granite counter tops and got the cut out for a double sink for $1.00 (yes a dollar). I had them cut it to my size and edge it for $45.00. All I have to do now is find some feet for isolation. Is sorbothane still a good isolation damper?

Thanks Everyone, Zuddie

Personally I would avoid the Transfiguration/VPI combo. I tried both a Temper Supreme and and Spirit III on my Classic and still got some IGD on hotter records. Tried all manner of alignments and protractors and eventually sold both carts. It was particularly hard to do because they sound so damn good most of the time.

I have an AT ART9 now and that is what I would recommend you start with. Will sound great with most any standard (60db) MC preamp gain.