Dropouts using ADAT bridge system

[Bellboy]

I have experienced dropouts when recording through my ADATs (blackface) and the ADAT bridge into Pro Tools ever since I've owned my system (from 11/2000). The dropouts are minute and intermittent and are heard as a disturbing click. I'm running Pro Tools as the master with my BRC on ext. sync at 48khz. The problem doesn't occur when the ADATs are recording simultaneously, but I don't always want to run ADATs. I've reinitialized my drives, and reinstalled the software, so I don't think that's the problem. Anybody else had this problem? Thanks. Bellboy

[ppine]

How long is the clock cable from your BRC in to your ADAT bridge out?

There is a limit before you will need to use a "T" connector at the BRC end with a terminator attached.

[baxter]

It would be worthwhile checking the sync reference and clock source cables. Most of the time such intermittent clicks would have a lot to do with correct clocking

[Mount Royal]

I didn't fully understand the wordclock cabling to your ADAT machines and BRC. But if you have the clock cables arranged serially with the BRC at the end of the series, you should terminate the wordclock line with a 75 ohm resistance. A T-port, as Ppine suggests, can be fitted with a termination. The BRC is said to not be internally terminated, so an outside terminus is needed. According to protocol, this is important irrespective of wordclock cable length.

Your wordclock cables should be 75 ohm coaxial material, RG59 spec. What you describe as clicks that are infact drop-out are suggestive of clock trouble. Honing in on wave forms in the drop-out region may infact expose "click" waveforms, as well as program loss.

John Caldwell

[Huby SEA]

If clocking is not the problem, maybe this: once a tech-head told me that the old black adat's recallibrate their A/D converters on a regular basis to put the offset back to zero, producing a very short break in conversion.... Are these clicks on a regular time intervall?


Huby