Let's start by easing some confusion. After looking it up, the DigiMax LT is a Presonus 8ch AD converter with ADAT output. It's not a wireless
system.
Digital can get clocking issues far too easily. Usually they show up as clicks in the signal, which seems to be what you are getting. It has to do with signal refreshes mid data stream.
Someone mentioned not having heard of issues using the internal Yammie clocks, now when used as a single device with only analog IO, there is no real need to worry about sync. Some people argue that some consoles sound better when externally clocked, but there is some evidence to suggest that with a single device, there is little gained in doing so as it still uses the internal clock, the device just syncs it's
phase locked loop to the external clock. I can't say whether it does or does not do things to improve the sound. There is a white paper written by one of the guys at Apogee on the matter...
Now that is all for a single device. You've got 2 with the AD and the
console. Now unless you have SRC on the inputs to the Yammie, which can correct the issue as well as allowing input at a different sample rate, albeit at a
latency and fiscal cost, then you need to have your devices synced some how.
As has been asked, could you let us know how the LS9 is currently clocking?
Given you only have the two devices, my advice here would be to go and find a piece of 75R
coax with BNCs and connect the wordclock out on the Digimax to the wordclock in on the LS9. Then set the Digimax at 48k. That should sync things up nicely. Termination - the LS9
word clock in is internally terminated. I won't get into termination here, but for what you are talking about, don't worry about it.
If your clock is bleeding into your RF, you need better RF. Clock runs a
square wave at 48 kHz. Even
VHF RF is running at 100MHz and
UHF higher. If the front end of the receivers can't filter out 48K, then it's absolutely rubbish.
And after all that, have you tried sticking a hardwired mic into the Digimax and seeing if that has the same issues and likewise if the radio mic straight into the
console behaves?