Phono Preamp Gain Question

Good comments by the others. Seconding Sarcher's comment, attempting to define "the lowest gain that a moving coil stage of a phono preamp should have" for a particular cartridge is risky, because different phono stages that provide the same amount of gain can differ widely in how much noise they generate in doing so. Also, comparing signal-to-noise ratio numbers for different phono stages is often an exercise in futility, because S/N specs are not consistently defined in terms of reference levels, and in terms of whether and how they are "weighted".

Also, the sensitivity of your power amplifier (the input voltage that is required to drive it to full power) is a factor to consider. If it has particularly low sensitivity, meaning a high sensitivity number, if the sum of the phono stage and line stage gains are too low you may not be able to drive the amp to full power even with the volume control at max.

My suggestion is simply that after coming up with a preliminary list of candidates, try to determine if others have used each of them successfully with the particular cartridge, or at least with similarly specified cartridges.

Regards,
-- Al

I agree that a phono gain of 56 to 65 or so should be just fine. My setup is pretty similar to yours in terms of gain. My MCs range from .25 to .35mv and my line stage has 15db gain. My power amps span low to high sensitivity, and my speakers range from 90 to 97db. I find a total phono gain (including MC step up) of mid-50's to mid-60's to be just right.

Here is the obligatory comment to a question about a phono preamp :-)

Liberty B2B-1

Good listening

Peter

PS I do make them - Thought I'd change up the post a bit :-)

You have a fairly low output cartridge and your line stage isn't on the higher end of gain options. While there is the variable of amp sensitivity and speaker efficiency, Salectric's speakers being very efficient so he needs less gain, I think with average sensitivity and efficiency even a gain of 60 is low for you. Bear in mind less will work, but noise becomes an issue.

My cartridge is .35, my line stage is 18db and my phono stage is 68db. But, my speakers are only 88db efficient. I may have a little more gain than I need from my phono stage, but I've gotten addicted to a dead silent background. You have a lower output cartridge and 6db less gain from your pre amp. Absent something on the amp/speaker end to reduce your gain needs, you need at least 65db.

I really like my Parasound JC3.

Tee shot: Your question is difficult as there is no specific answer without taking into all of your components from cartridge to speakers. I have a cartridge that has .28 db of gain. My phono stage high gain is 60 db but that is not nearly enough to drive my Soundlabs to acceptable levels (75-80 db levels). My preamp 15 db, amps 20 db,and speaker 86 db? ). Require the volume to be turned up where the noise level is unacceptable. I lowered the gain on my phono stage and added 14 db with a step up which brings my gain to 68 db. I now have a very quiet background that also requires a lower volume on the control dial. So, I would recommend a phono stage that would allow adjustable gain or purchase a step up transformer and experiment with several different brands.