Scope PCI Sync Plates

[yayajohn]

I was wondering if anyone has ever tried a Scope PCI wordclock OUT into another Scope PCI wordclock IN (on a different computer)
Just curious if it worked well or not.

[valis]

Why wouldn’t it? WC doesn’t differentiate between the device hosting it, it’s a duty cycle signal (square wave). I have Scope, Xite and 3 RME computers slaved to a black lion master clock and all are connected to Scope (PCI system) via ADAT/AES without issue.

[yayajohn]

Well I'm wondering how Scope PCI works as Master Clock out with a sync plate
or
As a daisy chain slave in and WC out to the other PCI.

Yes "in theory" it should all work fine. But does it?

[yayajohn]

Do you have the MkII or MkIII?

[garyb]

do not daisy chain wordclock.

if there are only 2 devices to sync, you can go one to the other. one needs to be master, one slave. the syncplate is master or slave based on what is set in Scope.

if there are many devices to sync, you need a distributor, which most master clocks are. you can go Scope as master to a distributor, then to all other devices which are slave. more usually, the distributor is master clock and everything else, Scope or whatever, is slave.

bnc word clock is often only useful when many devices are synced. if ADAT or AES/EBU is available, it might be simpler to just use those. there's no reason that you can't go bnc to bnc with 2 different Scope computers, as long as you properly choose master and slave(as long as there is only one master).

yes, it works.

the model wouldn't make that much difference.

[yayajohn]

Thanks gary
My question really is: If I"m clocking a computer from a master clock to Scope PCI sync plate in as slave, then run a WC cable from that sync plate out to another Scope PCI sync plate in as slave. Is that going to be a stable clock or
Is that what you mean by daisy chain?

[Bud Weiser]

... If I"m clocking a computer from a master clock to Scope PCI sync plate in as slave, then run a WC cable from that sync plate out to another Scope PCI sync plate in as slave. Is that going to be a stable clock or
Is that what you mean by daisy chain?

IMO, that´s already a daisy chain because you go from a clock receiving device (slave) into another one (slave too).
OTOH, it´s a short chain ... and might work.

But it´s not ideal,- like star type BNC wireing,- master clock to every "slave" separately.

Why don´t you run BNC from your master clock to each SCOPE Sync Plate separately?
Not enough BNC outputs on your master clock ?



Bud

[yayajohn]

Yeah I have run a separate WC to that computer. I was just curious if that was an option since it seemed pretty stable when I was doing that with an ADAT connection. I was also curious to hear of others experience with the sync plates. Generally speaking they work fine but sometimes I have to reload Scope and/or I get messages usually as the project is loading but once it's locked in it usually works fine.
They def don't like it when you mess with the settings.
Could be the master clock or maybe cables....who knows.
A new master clock is definitely on the horizon for me.

[garyb]

right, you should have multiple outs on the master clock. if not, you should have a distributor.

it will probably work as you suggest, but it is not correct.

adat sync is not the same as wordclock, which is sensitive to impedance.

[valis]

Correct, word lock is an electrical signal and daisy chaining through devices presumes that the device (being chained "through") has some way to amplify the signal, or was designed for this. Unfortunately that's not how the word clock specification works, and even in the case that a device is able to “derive” click from incoming signal and “regenerate” it internally, you will either have a phase shift (if PLL loop or etc is used, as with RME & Digidesign’s older gear) or a time offset (if a digital component is generating clock anew). The goal is that wordclock sync everything in the studio 100% phase and time accurate, not simply 'pass some form of clock along'.

Many devices will simply use the same electrical signal from the input when in slave mode, so this is where bnc T connectors and terminators enter the discussion, as you don't bother connecting the out but simply connect the T connector to the input, one side of that to the source clock, and the next side to the destination.

However a clock distributor or master clock with multiple outputs, as GaryB mentions, ensures each device gets the best quality clock signal from as the only loss will be due to cable length (presuming correctly terminated and specified BNC cabling is used).

[yayajohn]

Ok great thanks for the info. Does Scope equipment and converters need a terminator?
Will there be any noticeable signal loss with a cable length of 15'
What about the $85 WC cable?
Worth it? or Snake Oil?

[valis]

BNC, by specification, is never connected with a cable to both exposed connections. Because the cable itself has to be terminated to avoid reflections, a T-connector is used.

nic-coax-t-connector.jpg (18.81 KiB) Viewed 2257 times

If space is constrained, you can connect this to the host with a pigtail as in the following image:

bnc-t-connector-12064949.jpg (91.86 KiB) Viewed 2257 times

This can be confusing because as electronics became more tolerant (and as designs did) devices often included measures to ensure self termination. RME for instance does this.

The #1 best upgrade for my studio was a master clock with multiple (distrubted) outputs. Compared to that, having to buy the proper cables and connectors and properly connect everything was immensely worthwhile.

[yayajohn]

Hmm, I'm just running a straight cable from my master clock into the devices.
I might look into getting some of those T adapters and terminators.

[valis]

Imagine this is a string, and that when you start sending a waveform down the length it can 'reflect' back like with a small pond and ripples. This is what the termination prevents.

Again, with my RME devices they are 'tolerant' to being used that way, but RME still recommends proper termination. So when I was only connecting 1 RME device to Scope, and nothing else (via BNC), I did as you. I also had occasional issues with that, and more issues with mixing that and ADAT based devices. Moving to the full studio clock with proper distribution and wiring configuration has meant I can keep audio stable between machines that are on 24/7, and that includes TWO Scope machines (Xite and PCI) and FOUR other computers (3 RME MultifaceII units, and an RME PCIe Raydat card).

[scary808]

Love this thread! This is a bit of a sidebar to this discussion but still in the realm of ADAT sync. If an A16u is connected zlink does it act as a quasi sync plate for the ADAT i/o on the card?

[yayajohn]

Thanks Valis and Gary. I'm going to get those terminators going. Hopefully add some stability.
scary808: I don't think it works that way. You still have to clock your ADAT. Zlink is it's own thing.

[scary808]

scary808: I don't think it works that way. You still have to clock your ADAT. Zlink is its own thing.

If ZLink is clocked by by scope wouldn’t the wordclock present on the output of A16U be at the same rate/sync?

[astroman]

What about the $85 WC cable?
Worth it? or Snake Oil?

That kind of cable usually is for much higher frequencies than 44.1 to 96khz.
It looks like „regular“ wordclock, but is mostly used in modern video context iirc. Digidesign‘s 256x sample rate clock (aka Superclock) is another candidate for high quality cables, but it‘s just overkill in the sub 100khz domain.
I you need t-connectors: those are impedance specific, too. Get the 75 Ohm type.

[yayajohn]

That kind of cable usually is for much higher frequencies than 44.1 to 96khz.
It looks like „regular“ wordclock, but is mostly used in modern video context iirc. Digidesign‘s 256x sample rate clock (aka Superclock) is another candidate for high quality cables, but it‘s just overkill in the sub 100khz domain.
I you need t-connectors: those are impedance specific, too. Get the 75 Ohm type.

Ahh ok thanks Tom overkill for sure. Yes i will make sure they are 75ohms


scary808: the A16u is in slave mode when Zlink is selected.

[scary808]

scary808: the A16u is in slave mode when Zlink is selected.

Is WC disabled when in slave mode?