Apogee Big Ben Master Clock

[gaz7224]

Hi all,

I'm pretty much settled on a Big Ben.  I haven't had any major clocking issues so far, but I figure I'll need one when I start recording properly.  Even now, I hear a few clicks when I use my Triton-Rack via ADAT.

Can you make something operate at a higher clock rate than its internal clock?  I'm presuming you can't and are limited by the lowest native clock rate of items in your rig or 2x the native.

What clock rate would you use if you're not limited? Some say higher the better, but to me 48khz seems enough as it sounds OK and keeps audio file sizes reasonable.

Thanks,

Gaz

[stainless]

9I do not believe you can overclock with modifications.

I record everything at 44.1K/24 bit, except if it's for film/video (then 48/24 or 16 depending on whoever is synching things).  44.1kHz/16 bit is what CD's are.  MP3's will compress to whatever bit rate  you can select higher rates (I believe 192 kpbs is standard) and whatever protocols the converter uses (Codec)  I use L.A.M.E. ... as i don't save everything to a playlist or into a library, I find i-Tunes to be somewhat of a PITA

the higher the rates the more file size (space required)

BigBin is a well respected clock

[gaz7224]

Thanks Stainless.

Is there a limit on the length of the BNC/Coaxial cable?  Most of mine will be 2 meters, but the 1 will need to be about 5 meters.  That OK?

Gaz

[stainless]

I honestly don't know if there is a limit- general rule of thumb is to keep them as short as possible

all my BNC is right next to each other in the rack, so I'm using all 3M cables... even though they're longer than they need to be



I'm guessing the last piece of gear on the BNC daisy chain needs a terminator? (mine does)

[gaz7224]

I'm guessing the last piece of gear on the BNC daisy chain needs a terminator? (mine does)

I'm a wordclock novice - I didn't know you had to do this.

The Big Ben has 6 BNC outs, so I didn't plan on daisy chaining.  The manual says you can just WC OUT to WC IN for all of the 6 WC outputs.  Basically a 6-way distributor.

My Yamaha 01v doesn't have WC IN, but it has S/PDIFF and ADAT, so I'm presuming (because big ben has S/PDiff out), I'll be able to sync the 01V to Big Ben via S/Pdiff.

[stainless]

this from the manual:

Connecting Clock Signals
From the preceding information , these four Rules of Clock can be established:
1)   Ensure that all A-to-D and D-to-A converters are clocked by the most precise source possible, to ensure the highest quality for the entire digital audio system.
2)   Each digital device should be connected directly to the Master Clock Source with the shortest possible cable, in a “star” configuration.
3)   Each Word Clock line should be terminated with a 75 ohm load, as indicated by Big Ben’s Termination sensing LEDs. When the word clock input of connected devices is un-terminated, it’s acceptable to chain a few devices with a BNC “T” connector on the word clock input.
4)   Don’t delay the clock signal to any device by chaining a signal through input/output clock circuitry. Every device should receive the digital “downbeat” simultaneously.

You will need a terminator  I use all BNC, so I don't really know about using SPDIF for clock- I've used for audio, bit not for clocking

[gaz7224]

Thanks.

I think I understand now.

So, I need 75ohm coaxial cable and a bnc connector..  I also need a BNC connector with a 75ohn resistor for the end that goes into WC IN.  This terminates the signal to stop it going back up the cable.  I've found this: http://www.bryant-unlimited.co.uk/BC%2021 - which is a BNC plug with a 75ohm resistor built in and this sounds like what I need.  Have I understood this?

My mic pre terminates automatically, so I'm presuming I won't need to terminate that lead.

Can you use normal BNC connectors and add a resistor on? Like this: http://www.ebay.co.uk/itm/BNC-male-Resistor-RF-Termination-Impedance-75-Ohm-/380319194389?pt=LH_DefaultDomain_0&hash=item588cca5d15

Gaz

[stainless]

thta's what they look like

you'll also need a tee (male on the branch and females on the runs) the terminatort will on one run, the cable on the other and the male screws onto the gear

check with the manufacturer- My Presonius was pre terminated and they indicated I would still need the 75 ohm terminator (if it was the last one in the chain)

so i don't know if you'd be better off using one of the Big Ben BNC outs and a couple of tees with a terminator on the last.... or whether a single run to each would be better.

as I recall, the BNC was the biggest pain to get set-up so everything looked at the same clock in synch

I'd e-mail Apogee and say, here's my gear- what's the optimum way to connect?