Phono Preamp Gain Question


I am looking to upgrade my phono preamp as I have just acquired a much better cartridge. The cartridge has an output of .28mv; my tube preamp has gain of 12db. What is the lowest gain that a moving coil stage of a phono preamp should have for me to listen without excessive noise? I listen at realistic levels--medium to loud. I have read that some of the newer phono preamps without transformers--ARC PH6 or CJ TEA2se to name two, will not have enough gain for my application. Thanks in advance for your help.
teeshot

Showing 3 responses by jmcgrogan2

I'm using a 0.28 mV cartridge too, 60 db of gain in the phono stage, 20 db of gain in the line stage is MORE than enough for my system. I wouldn't recommend less than 56 db of gain for you.
Well the KAB calculator is based on the 5cm/s output (CBS standard). If your cartridge's output was measured on the JVC standard (3.54 cm/s), you will have to multiply your cartridge output by 5/3.54 = 1.41 to translate it to the CBS standard to input into the KAB calculator.

In other words, if your 0.28 is measured at 5cm/s, you can just plug it in, if it was measured at 3.54 cm/s, you will need to plug it in as a .39 mV (0.28 X 1.41).

I don't know how accurate that calculator is though. I have an identical cartridge output as you, 0.28 mV. KAB recommends an 'optimum' gain of 61 db, my phono stage has 60 db of gain, and that is MORE than enough. I never turn the volume knob past 10 o'clock. Granted, maybe you listen louder than I do, but I think KAB's measurements are overall preamp gain, including line stage.
Marty, since KAB doesn't know what kind of line gain the user will be using, they also must consider a passive line stage, with no gain. That's why I alluded to the fact that the 61 db of 'optimum' gain should be PLENTY, if using an active preamp.

Because I'm running a cart with the same output (0.28 mV) into a phono stage with 60 db of gain and a line stage with 20 db of gain and the gain is way more than I need. It seems like your situation is almost identical to mine, with similar results 80-83 db of total gain is much more than enough.

So the 61 recommended 'optimum' reference seemed pretty high to me using a line stage with an additional 20 db of gain. Though I'm sure it wouldn't be excessive if I were using a passive preamp.