No Lock on External Clock

[NigelC]

In a previous post discussed how to ensure proper clocking synching via BNC and running audio into the D8b via ADAT cards.

Have got everything hooked up and not getting external clock locked. Can get a lock when setting clock to internal but will not lock on an external source.

Setup:
D8b running 5.1 with Apogee Clock
Alesis HD24
iMac (Logic 9) with a MOTU 828 MkII Firewire
Art SyncGen (clock generator/distributor)

Have checked all cables, termination, sample rate etc. Have looked at other posts with tips and have tried removing FX cards, reseating clock card etc.

So do I give up with the Art SyncGen and use internal clock from the D8b to drive the MOTU and HD24 or is there something else I have done wrong (I have terminated the clock in cable to the d8b)?

[anyhorizon]

The Apogee Clock card is internally terminated. What you're doing is terminating the signal twice. Remove the external termination.

With 2 x 75Ω resistors in parallel, which is what you are doing, the resultant resistance is 37.5Ω. You're getting close to shorting the signal.

Peter

[NigelC]

How can I tell if the problem is the card itself? Does the fact it shows very briefly as locked indicate anything?

[Casey_Pittman]

Have you removed the external termination? Also the Art SyncGen IMO is un-needed in your described set-up. The apogee clock card is more than capable of handling this set-up. I occasionally work on a system similar to yours(d8b5.1-2408-HD24) and have been most pleased with the results.

Casey