Does anyone know of a way to connect an LP record player to a computer? I have a lot of my favourite music on vinyl, and I'm looking at a couple of programs I could use to clean up hiss, crackles etc. The main problem as I see it is connecting a 20 year old sound system to a modern desktop.

does your record player have RCA (phono) sockets as aux output?

your sound card will have aux in (line in) I've connected like that before now.

another way but not so good is use the headphone socket on your stereo connected to the aux in on PC

does your record player have RCA (phono) sockets as aux output?

Good question. I'll get back when I have a useful answer!

IF this record player (turntable) is meant to be connected to a stereo/home theater preamplifier or receiver in a home stereo or theater system, then I doubt seriously it has the necessary output signal strength to connect directly to any line-in of any audio device or sound card and produce anything close to acceptable quality sound.

The ONLY way this will work is if the record player has a built in phono amplifier (sound cards do not) - and that would be very uncommon - unless this record player is built in to some sort of all-in-one compact stereo system. The reason is MM (moving magnet) phone cartridges have a typical output of 2 - 4 milliVolts (1mV = 1/1000th of a volt) and a MC (moving coil) phone cartridge has even less, at .2 - .4mV. The potential (voltage) of a typical line-in signal, as expected by a stereo/HT preamplifier or receiver, or your PC's sound card, is around 2V. This is why stereo/HT preamps and receivers have dedicated phono inputs - because their is a phono amplifier that bumps up the phono signal to normal line-in levels. Note that normal RCA connections are used with standard turntables/record players so just because the connections physically are correct, unless that player sends the signal from the cartridge to a built-in phono preamplifier, the signal levels will not be correct.

So even if the sound card is sensitive enough to detect such a low signal, it would have to amplify it so much (by you turning up the gain/volume for the speakers), that any noise (and there's always noise) would become so objectionable, it would be unacceptable.

More importantly, LP vinyl records are recorded with a special equalization curve (RIAA EQ Curve) to compensate for excessive bass and attenuated high frequencies characteristic of and inherent to the vinyl recording process. Phono preamplifiers apply the opposite EQ curve during the playback process to "flatten" out the signal again. Playing back LPs without sending the signal through a phono preamplifier will yield unacceptable (and unfaithful!) reproduction of the recorded music. Sadly, many new home stereo and HT preamplifiers and receivers no longer include a phono preamplifier stage. It seems the makers think vinyl is dead. As a long time audiophile (my first love - long before I saw my first computer in 1975), I would have to disagree. Vinyl is very much alive - just listen and you would know.

If you are not too concerned with the best fidelity, you can get by with one of these inexpensive preamps. For the best reproduction of LPs over your computer, I recommend a Rolls VP29. Not exactly fancy looking - but when it comes to fidelity, it is not about what you see with your eyes.

This is more complicated than I'd anticipated. Apart from the considerations listed above my record player hasn't worked properly for a couple of years - actually, since the day I went to see Keanu in Constantine. I have always wondered if that was mere coincidence. But that's a side issue. If it was just a matter of getting the turntable fixed and plugging in the cable I'd go ahead. As it stands I need to buy something that I probably won't use ever again.
There are a few places in town that will do the transfer at a reasonable price. Given the hassles of a DIY I might farm the work out instead. I can still play with the music on my own computer anyway.
Thanks for the useful information, folks.