Sorry Axel, you're quite right -- Jsman in his OP didn't mention what knd of equipment he was using. If I were ever change anything in my system, it would be because I got a great buy on a used 326s! (with phono boards of course ;-)
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First, there is a nice writeup on calculating required gain on The Absolute Sound website, http://www.avguide.com/blog/taking-the-guesswork-out-phonostage-gain. If you plug your values into the formula (works nicely in Excel) you will see how much gain you need. One variable that hasn't come up in this thread is the voltage required by your amp to drive your speakers to an appropriate level, although the TAS write-up provides an "average value." As for personal experience, I have an ARC SP-8 preamp, ARC 150.2 amp, and Maggie 1.6QR speakers. The ARC specs say that the gain using phono inputs is 60db, and with a .5mv Benz MC cartridge, I get very adequate levels with the gain control around 12noon, i.e. at least in my set-up, 60db of gain works perfectly with a .5mv "medium output" MC cartridge. |
Hi Palewin -- I found these specs on the SP-8, which confirm the 60db gain from phono inputs to preamp outputs: http://www.arcdb.ws/SP8/SP8.html I think that one reason you are doing well with that combination of cartridge, preamp, and power amp is that the SP8's noise performance for the phono inputs is much better than it may appear initially, and is much better than it may seem based on cursory comparison with numbers for other preamps: Magnetic phono: 5µV equivalent input noise, wideband RMS (-66dB reference 10mV input) (Approximately 1µV above 200Hz or -80dB reference 10mV input) Those numbers appear to be "unweighted," while many phono stages and preamps specify noise performance with "A-weighting" or other weighting, in many cases without making that clear. A-weighting de-emphasises low frequency noise, and also extreme high-frequency noise, to reflect the fact that the ear is less sensitive at those frequencies than at mid-frequencies. So the 66db figure for your preamp (which is only 40db below the 0.5mv output of your cartridge) would be a MUCH higher number with A-weighting, and the 80db number would be somewhat higher as well. The Rogue unit, by the way, doesn't appear to have any spec on noise or signal-to-noise ratio at all. Best regards, -- Al |
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