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Grimm Audio CC1, Руководство пользователя

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Setup – Peripherals

1. On the “Synchronisation” tab: select device “Sync HD” and port “any” (the LTC 
input will be automatically selected)

2. On the “Machine Control” tab: tick “9 pins serial” (Sony P2). Untick “use serial 
time code for positional reference”. Leaving this option ticked causes the Sync 
HD to try syncing to video sync instead of word sync. An additional disadvan-
tage of Sony P2 is that it does not sport a “continuous resync” like LTC, signal-
ing time code only together with transport commands.

Setup – Session setup

3. Set Sync Source to “Word Clock” (the previous step will have automatically 
selected video sync instead, hence the need for executing the steps in order). 
The Loop Sync indicators will light up.

Controlling the external machine can be done in two ways:

a. The transport buttons on Pro Tools control the machine via the Sony P2 interface. 
The machine generates LTC. Pro Tools is slaved through the Sync I/O’s LTC input 
or any other LTC to MTC converter connected to your computer. Lock is achieved 
within one second. This is the preferred method.

b. Pro Tools is controlled directly by its transport buttons. The external machine 
locates and gets into play through Sony P2 locator commands. The user selects a 
cue point and hits play. The external machine will rewind to this time code minus a 
pre-roll and starts rolling. Pro Tools waits until it sees the correct time code coming 
back (Pro Tools slaves to the LTC of the machine). A potential problem occurs when 
the external machine fails to achieve sync during the pre-roll period. When every-
thing is slaved to word sync there is little chance of such a thing happening and one 
second of pre-roll should suffice. While playing, Pro Tools will run in trigger sync 
mode. That is, once it’s started playing it will ignore positional information, verify-
ing only that time code is still running. This method may for instance be selected 
when using hard disk video players.

6. Jitter and PLL’s explained

Jitter is an instability in the timing of a clock signal. Ideally the rising or falling 
edges of a clock signal are all separated by exactly the same amount of time. In 
reality, the timing is more uncertain. The graph below shows the time-domain view 
of the problem.

Содержание CC1

Страница 1: ...Please read this manual before operating the unit ...

Страница 2: ...TPInLB ...

Страница 3: ...troduction 4 Important Safety Instructions 5 1 Installing 7 2 Signal Connections 8 3 Operation 8 4 Setting up the Studio 12 5 Pro Tools 16 6 Jitter and PLL s explained 18 7 Specifications 23 8 Grimm Audio Limited Waranty 25 ...

Страница 4: ...of the reliable star distribution scheme The extremely low jitter of the CC1 clock outputs maximises the sound quality potential of the attached devices In case you need to slave your system to video clock please insert a Grimm Audio VCC video to word clock converter before the clock input Clock stability improvement and hence improved sound of digital live desks and digital snakes Clock distribut...

Страница 5: ...uien a petición se encargaría de enviarle la correspondiente traducción Please follow these precautions when using this product 1 Read these instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Dangerous voltage is inside this apparatus Opening is only allowed by qualified service personnel 6 Verify line voltage before use 7 Do not defeat the safety purpose of the...

Страница 6: ... with a cart stand bracket or table designed for use with professional audio or music equipment In any installation make sure that injury or damage will not result from cables pulling on the apparatus and its mounting If a cart is used use precaution when moving the cart apparatus combination to avoid injury from tip over 18 This unit runs slightly warm when operated normally Operate in a normal v...

Страница 7: ... low level noise due to stray magnetic fields Grimm Audio products have a real wood face plate that provides a beautiful and vivid appearance To maintain the outstanding looks one is advised to take some precautions Do not place the CC1 in humid nor very dry environments The wood might crack Do not use chemical or alcohol based cleaner on the wood AC Power Hookup The CC1 has a linear power supply ...

Страница 8: ...ry set line voltage value unlock behavior hold or mute 3 Operation Master mode The leftmost front panel pushbutton selects between two base clock rates 44 1kHz or 48kHz The two other pushbuttons determine the actual clock frequency trans mitted across the 16 BNC outputs They control in two groups Group 1 are chan nels 1 12 The second pushbutton sets the multiplication factor for this group to 1x 2...

Страница 9: ...The presence of the aes signal has no effect In master mode with the aes dip switch set to mute any signal at the AES3 input is basically ignored except that the aes lock light on the rear will be on to indicate the presence of a synchronous input 4 A signal is applied to the AES3 input that is synchronous to the CC1 and the aes dip switch is set to thru The AES3 output fully copies audio and subc...

Страница 10: ... AES3 signal instead The CC1 will never automatically switch from word sync to AES3 to prevent clock loops 4 No valid signal on either word sync or AES3 input The response is now deter mined by the dip switch named unlock When set to thru the clock frequency will be held constant within 1 ppm of the last valid measured frequency When set to mute the outputs will be muted In both cases the slave li...

Страница 11: ...o duces a 6dB loss resulting in a 2 5V signal All Grimm Audio products are designed to work in this manner There is no standard defining word sync connections As a result impementations vary across makes Outputs may be series terminated or low impedance DC or AC coupled Inputs may be parallel terminated or high impedance This yields 8 permu tations all of them encountered in the wild The CC1 input...

Страница 12: ...chronous This is what a house sync aka master clock is for Several formats are in use The AES promotes a standard called AES11 that uses an AES3 link but most equipment tends to use a word sync signal on a BNC connec tor The AES11 standard is to be amended to include this practice We think this is a good move since the purity of a clock recovered from an AES3 link is rather suscep tible to issues ...

Страница 13: ...edance reference plane at the rear insuring that it will never be affected by circulating currents Not all equipment is designed in this manner In case your system holds interfacing equipment that is sensitive to ground loops Grimm Audio has an isolation transformer available on demand CI1 Such devices degrade clock quality somewhat so they should be avoided when driv ing equipment of which the AD...

Страница 14: ...cillator that forms part of its PLL If the incoming clock happens to be much stabler than that the slow mode will actually end up adding jitter The latter scenario is almost guaranteed to be the case with the CC1 which is significantly cleaner than any clock oscillator we ve found in commercially available audio products so far As a rule in this case it is usually better to select the fast mode In...

Страница 15: ...nc you can either buy our VCC Video to Word Clock con verter or use any other generic video to word clock converter Connect the retreived word clock to the CC1 s word clock input and have the CC1 clean up the sync and distribute clock to the audio devices as usual The extraordinary stability of the CC1 s PLL will make sure the result comes as close as possible to making the audio chain master Hint...

Страница 16: ... by fooling the system into believe that Loop Sync is in use while actually a star clock distribution is utilized Star clock distribu tion has the advantage that it is more fail safe than daisy chaining and jitter gain of subsequent PLL s is avoided Connect an output of CC1 s group 2 to the External Word Clock input of the first unit in the chain if present the Sync I O otherwise the first 192 Con...

Страница 17: ... just for time code synchronisation The word clock connections are as described in the former paragraphs Pro Tools in music production Special attention is needed for the time code connection Up till Pro Tools 8 there was no way of combining the Sony P2 Machine Control time code signal with an external word sync like the CC1 Selecting Sony P2 forced the Sync I O to slave to video sync With current...

Страница 18: ...ithin one second This is the preferred method b Pro Tools is controlled directly by its transport buttons The external machine locates and gets into play through Sony P2 locator commands The user selects a cue point and hits play The external machine will rewind to this time code minus a pre roll and starts rolling Pro Tools waits until it sees the correct time code coming back Pro Tools slaves to...

Страница 19: ...find energy frequency frequency Amplitude Amplitude Jittery clock Jitter free clock slightly off the ideal frequency The red curve in the bottom graph shows only random jitter Sometimes jitter is periodical and then you wouldn t see a smooth slope but sharp peaks An im portant note is that frequency accuracy has absolutely nothing to do with jitter at all The red graph shows a jittery clock with a...

Страница 20: ...ake the converse the DAC is fine but the ADC took samples at the wrong time The effect is much the same What s worse in this case is that the numbers we ve recorded are now wrong In the previous case we could slap in a better DAC with a jittery ADC the game is over PLL s Converter chips need a high frequency clock signal usually something around 22MHz It is always made by a local oscillator anythi...

Страница 21: ...rnal sync signal Above the cut off point the PLL will not reproduce any errors present in the input but neither will it be able to cor rect errors committed by its own local oscillator Here s the transfer of a basic PLL designed to have a cut off frequency of 4kHz Mark that in this graph we are not looking at audio frequencies but at jitter or fluctuation frequencies The blue curve shows the atten...

Страница 22: ... Alternatively a too slow PLL might not correct a local oscillator of suboptimal qual ity In that case jitter performance is bad regardless of the quality of the external clock And here lies the rub a slow PLL will always make a converter sound the same but not necessarily good If a converter is insensitive to external jitter that alone is no indication that its internal jitter is low A slow PLL s...

Страница 23: ...channels Word clock output voltage terminated 2 7 Vpp unterminated 5 5 Vpp DC coupled Latency word clock in word clock out adjusted to less than 50 ns but may be larger due to input clock jitter Internal intrinsic clock jitter 2 1 ps RMS above 10 Hz Clock frequency master mode 1 2 or 4 times 44 1 or 48 kHz 10 PPM 5 50 C PLL performance slave mode 90 dB attenuation 10 Hz improving at 60 dB dec abov...

Страница 24: ...24 Grimm Audio contact information Grimm Audio CV Strijpsestraat 94 5616 GS Eindhoven The Netherlands 31 0 40 213 1562 Email info grimmaudio com Website http www grimmaudio com ...

Страница 25: ...Audio or an authorized Grimm Audio repair facility postage prepaid insured and properly packaged Proof of purchase must be presented in the form of a bill of sale or some other positive proof that the product is within the warranty period Grimm Audio reserves the right to update any unit returned for repair Grimm Audio reserves the right to change or improve design of the product at any time witho...

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