Shaky wrote:This raises 2 questions: a) Is it no longer necessary/desirable to use a preamp and b) does it make any difference to recording quality whether you reduce the source output or the Audacity input levels?
I can see exactly how you arrive at these questions, but they're not the right questions.
When recording from vinyl, the pre-amp does a lot more than boost the signal. The most important job that it performs is to "equalize" the frequency content.
In order to fit the waveform into the groove on the vinyl, the bass frequencies are made very much smaller than equivalent amplitude high frequencies. If this was not done, then the bass frequencies would rip the stylus off its mounting and send the tone arm skidding across the record.
Because the bass frequencies are made so small, if you play a record without the necessary (
RIAA) equalization, it will sound extremely tinny with very little bass. The main job of a phono pre-amp is to apply the necessary RIAA equalization so that the bass frequencies are amplified a lot more than the treble frequencies, compensating for the equalization that was used in making the record.
Phono pre-amps will also boost the signal to approximately "
line level". This is considerably higher than the signal level of a microphone, but is well suited for use in audio circuits. In the audio world, most of the work done with audio signals is done at approximately "line level". In professional audio, when using microphones, the first thing that is done is to amplify the microphone signal up to line level, and then all subsequent processing is done at this higher level.
So the "correct" questions would be:
1) Why does Vista/Win 7 assume that any input is a microphone?
A) Because Windows is increasingly orientated toward business and general consumer use and there is little interest in providing support for "specialist" applications such as recording. It is assumed that if you are plugging something into the audio input, then it's either a microphone for Skype/voip, or a microphone for voice recognition software, or a microphone for video conferencing (etc.).
2) What sort of audio hardware do I need for good quality recording from vinyl?
A) If you're using a phono pre-amp, then you really need an audio device (sound card) that has a good quality line-level input.
Alternatively, there are phono pre-amps that include the necessary analogue-to-digital conversion hardware and connect to the computer via a USB connection. This method bypasses the computers internal sound card.
Option 3, use a USB turntable. These devices include both the phono pre-amp and analogue-to-digital converters, though often the actual record player parts are not as good as conventional turntables.
Note: Even with a USB device, Vista/Windows 7 may try to configure the device as a microphone. In such cases it should be possible to set the "properties" of the USB device (in the Windows Control Panel) so that it records correctly as a stereo line level device.
