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Forcing a 48Khz unit to run at 44.1Khz

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Forcing a 48Khz unit to run at 44.1Khz

Postby molecular » Sun Jun 16, 2013 5:39 pm

I remember reading a post by Hugh somewhere on this forum that suggested that a digital unit that was specified to only run at 44.1Khz could actually run at 48Khz if it was given WC input as the difference was quite small and this specification only really refers to what the devices internal clock operates at...

I have the opposite plan, which is basically that I have an Aphex 142 AD which "only operates at 48Khz". It's not a problem really, although it has been an inconvenience. But I recently added an M Audio Octane to the rack which has a WC output, so I'm wondering can I slave the Aphex to the Octane and successfully force it to run at both 44.1 and 48?

The other complication is that I'll be using the WC out from the Octane, even though I won't actually be feeding the ADAT out from it to my interface, and I have a 002R with no WC in or out ... so the route will be WC out from the octane via a T-junction to the aphex 142 and an audient mico. Aphex 142 to 002R ADAT IN and mico to SPDIF IN. Slave the 002R to the ADAT IN.

Is there any aspect of this (especially the sample rate issue) that just isn't going to work?

Thanks!
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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby James Perrett » Mon Jun 17, 2013 10:09 am

Unless you can find someone else who has used the Aphex in this way, you are probably best off just trying it. If the Aphex has a suitably wide clock bandwidth you'll be OK although I might be tempted to use the Mico as the sync reference in the full system as it will probably be happier at 44.1kHz.
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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby Hugh Robjohns » Mon Jun 17, 2013 3:09 pm

Aphex do seem pretty adamant that the 142 will only run at 48kHz, even when externally clocked. It really all depends on how wide the slave-lock window is on the Aphex's PLL, and the only thing you can do is try it and see if clocking at 44.1 produces a stable 44.1 output.

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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby molecular » Mon Jun 17, 2013 4:35 pm

Give it a go it is then!

I'll try and remember to post back what happens...

But the Mico has no BNC out, so I'll have to use the Octane as the master clock. Is that what you meant?

Cheers!
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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby damoore » Mon Jun 17, 2013 6:42 pm

Even if it looks like it is working, you may still get the occasional click. That, at least was my experience when I accidentally set my QS8 to one rate and my interface to the other (this was syncing to the ADAT output on the QS8)

Note too that if you switch to the internal clock, say when mixing, you will be back to 48Khz, so everything will be way sharp.
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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby James Perrett » Tue Jun 18, 2013 9:36 am

molecular wrote:

But the Mico has no BNC out, so I'll have to use the Octane as the master clock. Is that what you meant?

I meant slave the 002 to the spdif from the Audient rather than the possibly dodgy output from the Aphex.

James.
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Re: Forcing a 48Khz unit to run at 44.1Khz

Postby molecular » Wed Jun 19, 2013 10:01 pm

James Perrett wrote:
molecular wrote:

But the Mico has no BNC out, so I'll have to use the Octane as the master clock. Is that what you meant?

I meant slave the 002 to the spdif from the Audient rather than the possibly dodgy output from the Aphex.

James.

Gotcha.

Today I learnt two things...

1. It doesn't work. Just a horrible mess of clicks coming back from the Aphex and the LED goes a funny colour that's not described in the manual, which I can't imagine is ever a good sign, so I'll be a 48K man only for a while. Worse things happen at sea, at least I'm getting my money's worth of IO for a while.

2. When splitting BNC cables, buy cables with L-shaped connectors at one end. I found a way of making it all fit eventually, but it's not pretty back there.

Thanks for the tips!
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