Most studios include a number of digital devices, but in order to get them to converse in the digital domain, they have to run at the same sample rate and be synchronized to the same sample clock. At its simplest, this can involve a coaxial cable connecting the digital output of one device to the digital input of another set to external sync mode — providing both pieces of gear are set to the same sample rate. The two most common sample rates in the typical project studio are 48kHz (consumer audio and pro broadcast) or 44.1kHz (the CD sample rate), but not every piece of gear is switchable between the two. For example, in my own studio, my ADATs/BRC and 03D mixing console run at 48kHz, but I like to record my DAT masters at 44.1kHz so that I can make audio CDs from them. There are two ways to get the desk to talk to the DAT machine — I could either use an analogue link between the 03D and the DAT machine, or use a sample‑rate converter.
Sample‑rate converters can be costly, but not Friend Chip's SRC/W DT50. How do they do it? In order to really simplify things, the SRC has no controls whatsoever. What you get are an S/PDIF input and an S/PDIF output, and providing the input signal's sample rate is in the 25 to 50kHz range, whatever you feed in is automatically converted to 44.1kHz. All the user has to do is remember to connect the input and output the right way round.
I tested it between my 03D and my DAT machine and couldn't detect any subjective difference in sound quality between the 44.1kHz sample‑rate converted version and unconverted transfers at 48kHz.
A simple box like this is hugely useful, especially if you have an edit system where you're likely to encounter 48kHz DAT tapes, or worse still, DAT tapes containing a mixture of 44.1kHz and 48kHz recordings. Just leave it in line and nothing will catch you out.
Should you need something a little more flexible, the more expensive DT60 SRC/W offers a choice of 32kHz, 44.1kHz or 48kHz sample rates as well as word clock in and out, SCMS management, pre‑emphasis handling and pro/consumer format conversion. Paul White