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

I also run an Orpheus L with a phonostage with 60 db of gain.  I have enough gain from the phonostage.  However, I don't know about the amount of gain provided by my linestage or the input sensitivity of my amp, so it is hard to translate my experience into how anyone else would fare with 60 db of gain.  If I had an additional 3-6 db of gain, that might be desirable, but, as with anything audio, that would probably come as a tradeoff in some other area of performance.

Hi Larry,

Congrats on your Orpheus L. Your inputs elsewhere on this forum helped me to decide on buying mine. Much appreciated. 

I get enough volume with the Ayre set at 60db, but think that it would be optimal to have my preferred listening volume occur at the unity gain position or below on my pre's volume control rather than above, thus my comment on wishing I had a bit more gain from the phono stage. 

Going to a 0.2mV cartridge would make this even more of a challenge.

Dave

Battery powered ZYX CPP-1 headamp (pre-preamp) designed for 0,24mV MC cartridges and compete with the finest suts ever made according to Arthur Salvator’s info. It has additional 26db step-up ratio for your MM input to drive LOMC cartridges. This is a very special device! ZYX own input resistors made of cryo purified chrystal copper wire (they use the same in material for their mc coil). The resistor is made by winding the wire to a coil that has no inductance in a special process. No noice and no infuctance at all. With this device all you need for LOMC is just MM stage.

So in addition to regular MM stage +26db with headamp for 0,24 mV MC is enough.

I owm Zyx CPP-1 and never had probs with LOMC. 

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