Phono stage gain

Try the phono preamp gain calculator at www.kabusa.com

In my experience it's pretty much dead on.

You could check with AR for their recommendations.

Is the Grado Gold one of the MM level output cartridges (e.g. 4 to 5 mv)? If so, you'll have more than enough gain.

I owned one of the Mk I versions of this preamp. It had in the region of 62dB gain (phono plus line stage), and I don't think they changed this in subsequent upgrades, but it's best to check.

Using this 62dB gain as an assumption, it would predict (all things being equal), that it would be fine for down to a medium output MC cartridge (i.e. 1.0 mv).

Now, in speaking about phono/line stage gain, you need to put this into the context of the gain structure of your entire system. You can't restrict your analysis to your phono and line stage.

Additionally, you can get by with a theoretically unfavorable gain relationship if your system has ultra quiet components along with a power amplifier that has lots of headroom with respect to driving your speakers. Think of your system gain structure as an ecosystem with all components interacting.

I ran my SP-9 Mk I with a low output MC cartridge (.3mv), as all of the components in the signal path were quiet, and my power amp at the time had a lot of grunt to drive my speakers.

I have a thread on my forum that covers on these issues. If you're interested in reading it, it's over here (complete with some sample system gain calculations):
http://www.galibierdesign.com/phpbb/viewtopic.php?f=13&t=35

Cheers,
Thom

Thom,
I think you really summed this up perfectly, thank you. I am using a MC cartridge with .4 mv output, an AR SP14 pre amp (I think it's spec's are 66db phono output), 30 watt per channel SET mono block amps and 104 db speakers (horn loaded), all in a large room. Although I get very favorable volume levels with no noise whatsoever, my gain control is much higher up the scale than with CD source. Do you feel a phono stage gain would benefit here or leave well enough alone?

Hi Mark,

Having lived with high efficiency speakers for some time now, I can tell you that this is likely the biggest challenge for the designer of a phono stage - keeping things quiet in the context of 98-110dB systems.

On the surface, you look to be just about right in your gain structure - making up a few dB in your power amp/speaker relationship where you're just a wee bit shy in the cartridge/phono/line stage part of the signal path.

Of course, if your volume control (when playing phono) is in the 12-2 o'clock position then you have the added bonus of burning off less signal through your volume pots which in general is a good thing. In a real noisy preamp this might be a liability of course, but ARC products are typically silent.

Many people are led to the erroneous conclusion that having a gain structure where the volume control is barely cracked open is a good thing, which in most cases, it is not.

We're splitting hairs here, and I wouldn't stress out over a less than perfect arrangement (volume control position / gain), but it's something to keep in the back of your head when you're swapping gear in and out.

If your sonics are fine, then I'd leave well enough alone.

Cheers,
Thom @ Galibier