ADAT, like other digital audio protocols, doesn’t affect the analogue stages of either connected device — once converted to digital the signal is passed through unchanged.
I’ve read lots of Hugh Robjohns’ articles on the SOS website, and they’re fantastic. I have some questions about preamps and interfaces, and hope he can answer them! First, if I connect an eight‑channel preamp (118dB A‑weighted of dynamic range) using an ADAT cable to a poor‑quality (105dB dynamic range) interface, will I lose signal quality? My concern is that maybe I could lose dynamic range because the audio interface has only 105dB conversion. Is that right? Also, if I connect a poor‑quality eight‑channel preamp (again using ADAT) to a fantastic audio interface, will I get a better dynamic range from the source preamp signals?
Roberto Estrella
SOS Technical Editor Hugh Robjohns replies: The answer to your first question is no, you will not lose quality. The dynamic range figures in the specifications apply only to signals passing through the unit’s A‑D and D‑A converters. Where you’re routing signals through an interface’s digital inputs — ADAT in this case — these completely bypass the converters and they are passed straight on through to the computer. So if they come from a preamp/converter with 118dB dynamic range they’ll still have that when they arrive at the computer.
For the same reason, the answer to your second question is also no. Again, the signal dynamic range is ‘baked in’ during the original conversion from analogue to digital. The quality is set by the original conversion process, and the digitised signal is passed through unchanged.