Copying vinyl to CDsBy Chris Johnson. Published: 11th Feb 2006, 18:56:22 | Permalink | Printable
Play it again, SamAlthough vinyl threatens every other year to be the new hip in-thing with all the cool kids on the streets, there's still a wealth of age old audio joy locked away in collections of deteriorating records littering lofts and cupboards everywhere. Chris Johnson talks us through how he preserves his LPs onto CD using RISC OS.
Essentially all my experience has come from using a RiscPC fitted with an Irlam i16 audio digitiser podule card. This was a cut down version of their original video recorder, and contains only the audio recording and playback. The card has both analogue and digital inputs, although I only use the analogue input. The audio analogue input requires a signal level of the order of 250mV, so the source requires preamplification and frequency equalisation prior to being fed into the card.
The system I used consisted of a Garrard transcription turntable from many years ago. It was originally connected to a 'home' built preamp/amp based upon an original design by Bailey in Wireless World. However, that had been sent to the tip some years ago, so I purchased a small preamp/mixer unit from Maplin. This provided RIAA equalisation for magnetic cartridges and preamplification to line level. It also had independent level controls for each input, (phono, mic, and aux), and a master output level, allowing the signal level to be easily controlled. Having now looked in the latest Maplin catalogue, there does not seem to be anything similar now available.
The Irlam software provided with the card was basic but completely functional. It included level controls and balance, which I used for fine adjustment, and an oscilloscope type display, which sampled the input waveform to allow a check for signal level and clipping. The record was played and the level could be adjusted to give a good overall level but without clipping on loud peaks. Once satisfied that the level going to the digitiser was satisfactory, the recording could then be made, and it is as easy as clicking on the record button and restart the record playing. Keeping the oscilloscope display going while recording allowed adjustment of level if necessary, although if the level was obviously too high or too low on a particular track, I would abort the recording and start again, rather than have level changes within a recording.
There were reports at one time that the Irlam audio card had problems with long recordings, but I found I could always record a complete side of an LP in one go. Once the recording was finished, the Irlam software inclued some primitive editing capability which allowed the 200+ MB .wav file to be split up into tracks as appropriate. It would also play .wav files so the quality of the actual recording could be checked if necessary. I found that in general the Irlam card worked very well, certainly for my purposes.
Since all my LPs had been well used, but also well cared for in handling, they were generally in good condition. However, they had been stored for some years without being used. I did try to clean them up before making an actual recording. This involved making up a solution which was half and half isopropyl alcohol and deionised water. To this was added about 1% of a wetting agent, a photographic chemical obtained from Jessops. Using a clean, lint free cloth soaked in this mixture, the surface of the record was gently wiped to remove any surface dirt. While the surface of the record was well wetted, it was 'played' using just a "Dustbug" type cleaner - a small plastic arm with a nylon brush and felt cleaning pad. This was sometimes repeated two or three times. The record was then played with the actual pickup at least once before any attempt to make a recording. I tended to set the pickup tracking weight to the upper end of the recommended cartridge operating range, rather than at the bottom of the range. After this treatment, most records sounded remarkably free of surface noise and dust.
You will need a pre-amplifier that's suited to LPs to bring the output from the pick-up needle up to the correct level and apply the RIAA equalisation. Feed the record output into the pre-amplifier unit, and then feed the output of this into the computer's audio input. Set up your audio digitiser to dump the incoming audio feed to disc as one long .wav sample.
Be prepared to shop around for a vinyl friendly pre-amp, they're inexpensive and can be found lurking in hi-fi shops and similar stores. The Irlam i16 is recommended but now hard to find. You could use a RiscTV card, which has an audio input, although it will save the recording in Replay format. The LP tracks can be split up with a suitable sample editor, then burned the CD with CD Burn.
Originally I used a SCSI Yamaha 4416 CD writer on a PowerTec SCSI card with CDBurn. This was always a bit hit and miss, and after a while became very unreliable, so I binned it and bought a quite pricey Plextor SCSI CDwriter. This worked well for a couple of years, but once RISC OS Select came along with frequent upgrades (I was a beta tester for a while) it stopped writing reliably, although this is maybe a coincidence. However, having had an Iyonix from its first release, CD writing on this machine has been 100% reliable, so it became a matter of transferring the .wav files over ethernet from the RiscPC to the Iyonix for burning; rather time consuming but it worked.
When transferring an LP to CD, I usually tried to do proper inserts and so on. This involved scanning the cover of the LP. Since I only had an A4 scanner the cover had to be scanned in two halves, using David Pilling's Imagemaster as it then was known. Since the cover would just about fit the scanner in the vertical direction, I temporarily fitted an additional guide at the top of the scanning area so the cover could be carefully slid sideways on the scanner bed while keeping the vertical position and angle as constant as possible. This resulted in two images with some horizontal overlap, and possibly a little vertical misalignment. The two halves were loaded into Rob Davison's Compo, trimmed as necessary and joined together. With care the join was unnoticeable. If any touching up of the final 'cover' was required, this was done in Photodesk.
I have never used the Iyonix in anger for digitising audio using it's mic-in socket. I have tried using the analogue output from a DAB radio, and the result sounded ok, but the source was not particularly high-fi. DAB is a bit of a let down, and I only have one 'cos it was a Christmas present from my wife. I still have some LPs to do, but since my 'computer room' is a small box room, there isn't room for everything, and after converting a few LPs, the audio setup goes back into storage. I hope to set up the record deck again at some point, and will give the Iyonix a whirl to see how it performs, since it would be more convenient than getting the RiscPC set up again.
Compo, Photodesk, Dave Pilling's scanning software and CD Burn
Irlam i16 cards are no longer available as new, so be prepared to do some digging around on ebay, usenet and user groups
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