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

The Cartridge output is a pinch point if your phono stage is not sensitive to amplify the signal if at all . It just won't be heard .
With the cartridge will be of critical importance as the "first component" which feeds into the the phono stage which has different capacities to amplify the signal it's gain and the chain comences to the line gain into the power amplifiers gain. If you get a good signal of reasonable db then you simply have to decide if you want one or the other of your components to carry the bulk of amplification. I will give you an example of the phono stage overwhelming the rest of my gear. If you are doing your system unconstrained by the expenses. Then you can likley find all the componenets to be on par with eachother. That is have all your components equally good at doing the work. The mere mortal usually find a way but some sacrifices may be necessary.
I like my main power amp's sonics. Therefore I want them to do the amplification.
A high gain preamp such as my ARC SP6B pre with phono has so much gain that it dominates the sonic signature of the system to that of the preamp/phono.
The power amps get very little work to do. The problem is that I love tubes. They are truly magical in my view except when you have to have the lowest noise floor possible. As such I prefer the hyper neutral ultra quiet of an SS phono stage.
I have switched to a tubed pre line stage and but it is fed by a Graham Slee SS phono stage. Which adds a certain harshness that I didn't want and the hunt goes on, for now it's very good, but I want perfection.
Anyone want a preamp.......great with low output cartridges that are so quiet they yield a negative number.....