MC Phono Pre Gain

It's hard to say specifically, because there are so many factors that come into play. How large is your room? How sensitive are your speakers? How loud do you listen? How much gain do your amp and line stage have?

All of that being said, I would probably recommend at least 60 dB of gain for your phono stage, possibly more, depending on your ancillary equipment, room size, and listening preferences.

I second several of the comments that have been made to the effect that not enough information has been provided. Most importantly, what is the gain of your line stage preamp, and what is the sensitivity of the power amp (i.e., the input voltage that is required to drive it to full power).

I would also emphasize the point made by ActusReus to the effect that equal gains provided by different designs are by no means necessarily equal in terms of their noise performance. For instance, while I would have high confidence in the Ayre phono stage that was suggested by Zd542, given his comments about its noise performance (as well as the knowledgeability of his component suggestions generally), I would not assume that other phono stages providing the same gain specifications are necessarily suitable.

Regards,
-- Al

Thank you very much for your responses. First, they've given me a greater understanding of the complexity of the question I asked. I appreciate the mini-seminar in preamp gain. Second, I confess to utter ignorance of these points. For those who asked specific questions about gain and sensitivity, the short answer is: I don't know. I have an Aikido preamp which, at the loudest levels I listen, never goes past 10 o'clock on the volume knob and a pair of Quicksilver M80 amps. I looked through online information for both and cannot find out the gain of the linestage or the sensitivity of the M80s. That said, the ballpark figure of 60 dB will give me something to shoot for.

Thanks all for the responses.
GP

It looks like the sensitivity of the M80 is 1.5 volts, as indicated in the manual here, which is neither particularly high nor particularly low. The Aikido preamp appears to have existed in a number of different variations, using a number of different tube types, but after doing some research I suspect that its gain is probably a bit higher than average, perhaps 15 db or so. If you indicate what source you are presently using, which results in the volume control being at 10 o'clock or less, it might provide added confidence in that figure, as a rough approximation.

60 db + 15 db = 75 db, which corresponds to a voltage multiplication of about 5623 times (based on 20log(Vout/Vin)).

0.15 mv x 5623 = 0.84 volts.

With a phono stage gain of 60 db, and assuming 15 db preamp gain, that is the voltage that would be going into your power amplifier, under the standard test conditions for which the 0.15 mv is measured, with the preamp's volume control turned all the way up. Very loud musical peaks can cause a cartridge's output to exceed its output under the standard test conditions by several times or more, as I understand it. So with 75 db total gain in the phono stage and preamp you would be able to obtain the 1.5 volts that is necessary to drive the amp to full power under those conditions, without running out of range on the volume control. But a little more margin would seem desirable, especially given the uncertainty about the gain of the preamp. ActusReus' suggestion of 67 db for the phono stage seems very applicable.

Before settling on a specific phono stage it would be prudent to try to determine, via research or by starting a new thread, if others have obtained adequately low noise levels when using that specific model with cartridges having similarly low outputs. That is something that usually can't be determined from specs, especially if a very low output cartridge is being used, because signal-to-noise ratio specs tend to be defined both inconsistently and incompletely.

Regards,
-- Al

Al,
Thank you for your thorough and enlightening response. I appreciate the thought that went into it.
Regards,
GP