Turntable

hifi

My brother recently lent me his old turntable, which he had given to his fiancé before he had made her a custom, home-made one. It's an old but still very serviceable Project 1.2, which needed a new cartridge. Unfortunately, the tone arm rest doesn't have a retaining clip over it any more, and when it was being transported, the tone arm — complete with bare stylus — jumped out of the rest and gouged a furrow in the base of the turntable. Needless to say, this isn't to be recommended, and the stylus looked like a tiny, blackened stump after the accident.

I bought an Ortofon OM10 cartridge (complete with the obligatory 'but she's a girl...' moment, where the assistant looked startled and panicked when I asked if there was a paper tracking alignment gauge included in the box), and spent some time this morning setting it up. Turntables are pernickety beasts.

I'd also borrowed a stylus down-force gauge from my brother1, and a paper tracking alignment guide to align the cartridge correctly with the groove (it turned out that there wasn't one in the box after all). So, my job for the day was to align the cartridge correctly, balance the tone arm so that approximately 15mN of force was applied through the stylus, and also set up the vinyl to analogue converter (VAC) that I had also been lent (my amp doesn't have a phono stage).

The tracking and tone arm adjustment was a bit fiddly but not too difficult, but adjusting the VAC turned out to be quite a challenge. My brother warned me that I would probably have to set some jumpers on the circuit board inside the VAC to provide the correct resistance, gain and capacitance for my cartridge. Getting the circuit board out of the casing was a little scary, as you have to flex it slightly before pulling it out. Then I was faced by load of complex electronic components and a circuit diagram. According to the instructions, I would have to subtract my input cable capacitance from the specified optimum load capacitance (in that swashbuckling unit, the pico Farad or pF). Maths! It was clear that I was in trouble.

After an intense perusal of the diagram and instructions, and looking at the information for my cartridge, I managed to set resistance to the recommended 47kOhms (remove all jumpers — well, it was getting a bit hot in there), the gain to 32dB and the capacitance to about 200pF (though I'm still not entirely clear that this is correct). I put it all back together again, plugged everything in, placed a record on the turntable, gingerly dropped the stylus into the groove, and stood well back. It worked! Better still, it sounded great. Sweet, rich and very clear. I'll talk more about the actual listening experience (and my vinyl-buying expedition) later.

1 Actually I ended up with one each from my brother and Dad; these are the kind of people who always know where their spare stylus down-force gauges are. Well, you never know when you might need one.

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