Tuesday, August 29, 2006

The Art of Science

Since the initial blush of enthusiasm after the arrival of my Project 1.2 turntable I’ve been strangely silent about the subject. That mostly has to do with the fact that while I have been enjoying it, it’s been a bit of a love/hate relationship. Allow me to elaborate. When listening to CDs the volume on my preamp is usually set to about 9 O’clock. On records this had to be substantially increased. I’m well aware that the output of a phono stage isn’t going to be as powerful as that of the average CD player or DAC but this was out of the range of normality. At 4 O’clock on the preamp’s volume control I still wasn’t getting a similar output, and the sibilance on vocals was distracting to say the least. At lower volumes, the sibilance wasn’t present so I began to think that the volume setting was just too high on my preamp.

The first attempt at solving the problem was to try setting the Project Phono Box to the moving coil setting to get more gain even though my cartridge, a Grado Gold is a moving magnet (Grado actually refers to it as a moving iron.) That did increase the gain to an acceptable level but it also wreaked havoc on the frequency response. High frequencies became MIA while the bass became over whelming. This lead to the thought that maybe a phono preamp with more gain was necessary (us audiophile can turn anything into an excuse to upgrade.)

So I brought home a Project Phono Box SE. It was slightly better sounding but gain was still an issue. Again switching over to the MC settings was tried with the same result. Then while looking at the DIP switch an idea emerged. I notice that on the Phono Box SE switches 5 and 6 were in the UP position on both MC settings and DOWN for the MM setting. This lead me to think that the switches might have to do with gain. All of the other switches were left in the MM positions except for 5 and 6 which were moved to the up position. To see the diagrams in question please consult http://www.sumikoaudio.net/project/manuals/phonoboxse.pdf for a diagram. Again this provided acceptable gain but the frequency response was off, not by as much as it was with the Phono Box trying the same trick or the MC settings for the Phono Box.

Original Phono Box MM positions:

Original Phono Box MC positions:

New Phono Box MM position:

This arrangement gave me the gain and frequency response that I wanted.

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