The cheap option, if you can be bothered, is to buy the CD drive used, plus an external case for it, a SCSI lead and, probably, a SCSI terminator. Only three drives are compatible. They are the TEAC CDW512S, TEAC CDR56S, TEAC CDR58S. These are the drives used in Tascam's various versions of their burner. You can get them on Ebay. This is what I did. However, buying Tascam's own burner is easier and there's always the risk when you buy the bits separately that it won't work.