Lavry 4496 User Manual

LavryBlue Series

Model LE•4496

Modular Audio System

Operations Manual

Lavry Engineering, Inc.

PO Box 4602

Rolling Bay, WA 98061

[phone]

http://lavryengineering.com/

e-mail: [e-mail]

Revision 2.0C

April 2007

LavryBlue Operations Manual

Table of Contents

Page

1) LavryBlue 4496 System Overview 3

2) M•SYNC Multi-channel Sync Module

a) Overview 4

b) Operation 5

c) Specifications 6

3) M•AD-824 Analog to Digital Converter

a) Operation 7

b) Settings 10

c) Specifications 12

3.) M•DA-824 Digital to Analog Converter

a) Operation 13

b) Settings 15

c) Specifications 16

4.) MicPre Microphone Preamplifier

a) Operation 17

b) Settings 18

c) Specifications 18

5.) Opening the 4496 19

6.) 4496 Chassis Specifications 19

7.) Warranty 20

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LavryBlue Operations Manual

LavryBlue 4496 System Overview

The LavryBlue System is a modular 1U high 19 inch rack unit, configurable to accommodate multiple
functions including Digital to Analog conversion, Analog to Digital conversion, and Microphone Pre­amplification. The hardware is designed to operate at industry standard 44.1, 48, 88.2 and 96 kHz sampling
rates, with the additional flexibility in “Wide Mode” of operation from external clocks at non-standard or
variable sample rates in the ranges of 42 to 50 kHz and 84 to 100 kHz.

The Lavry Blue chassis contains a power supply equipped with additional output power noise filtering. The
modules are bolted in and connected to each other in a daisy chain manner, enabling power distribution
across the chassis. This interconnection also provides for communication between the units that in some
cases are user selectable. One of the advantages of this approach is the ability for AD converters to “share”
a common clock source- the M·SYNC- to minimize jitter and operate multiple channels in phase.

The chassis provides room for up to 4 “single width” modules. Most modules are single width 2-channel
units, so the chassis has space for up to eight channels of conversion or processing. The MicPre is also 2­channel, but it takes up the space of two AD or DA modules, so one chassis can provide up to four channels
of microphone preamplification. Each module has a front panel and a rear panel that are directly in-line
with each other from front-to-back in the 4496 chassis.

This flexible design means that the Lavry Blue chassis can be configured to accommodate anything from a
single module for stereo AD or DA conversion, to a maximum of eight channels of conversion. The unit
may be configured for any mix of functions- for example: 2 channels of AD and 2 channels of DA, or 6
channels of AD plus 2 channels of DA. One popular configuration is 2-channels AD, 2-channels of DA and
2-channels of MicPre. Another advantage is that the LavryBlue can initially be purchased in a “minimal”
configuration and then later upgraded to add more channels or different functions, as the user’s needs
change. Please see “Opening the LavryBlue 4496” on page 20 for details.

All modules are added left-to-right. Because the M•SYNC provides the clock source for all A-to-D
conversion, the M•AD-824 A-to-D modules must be grouped together on the left side of the 4496 chassis.
M•DA-824 D-to-A converters are placed in the next available slots to the right of the A-to-D’s. The MicPre
would be furthest to the right in 4496 units with converter modules. The MicPre is a doublewide module,
and thus would occupy two “slots.”

Another aspect of the modular approach is that all analog audio and AES/SPDIF digital connections are
made externally. The only interconnecting signals internal to the 4496 are detailed below under “Shared
clocks and settings.” For example, this means that if you wanted to record the MicPre output using the
M•AD-824, you would need to connect XLR cables from the MicPre output to the M•AD-824 input. Or, if
you wanted to monitor the M•AD-824’s digital output through the M•DA-824, you would need to provide
an AES digital connection to the M•DA-824 from the M•AD-824 or the device the M•AD-824 is feeding.

Shared AD clocks and settings: Operating multiple channels of Analog to Digital conversion with
independent clocks can creates timing or “phase-shift” differences that degrade sonic imaging. To avoid
this problem, a Master Sync unit (the “M•SYNC”) controls the clocks of all AD converters in the 4496
simultaneously. It takes the form of an additional printed circuit board that is controlled by the panel on the
left side of a LavryBlue equipped with AD converters. In multichannel systems, user settings such as word
length or dither are typically the same across all channels, so a selectable “Master-Slave” mode is available
on the M•AD-824 module. This allows the front panel parameters set on the Master module to be sent to
the Slave modules so that each module does not need to be set individually.

Stand alone DA modes: The M•DA-824 digital to analog converter functions well as a stand-alone unit.
CrystalLock jitter elimination enables the M•DA-824 to clock externally while virtually eliminating the
audible effects of source jitter. Independent operation also means multiple signals at different sample rates
can be converted asynchronously from digital to analog in the same 4496 unit equipped with multiple DA
modules. Although the DA’s operate independently, the CrystalLock™ and Narrow modes have a fixed
“propagation delay,” so the outputs from multiple DA’s clocked from a common source remain coherent.

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LavryBlue Operations Manual

M●SYNC Multi-Channel Sync Module

1.) M•SYNC OVERVIEW

The M•SYNC supplies the clock signal for all M•AD-824’s in a 4496 frame. It is controlled by the left­most panel on the front of the 4496. If there are no M•AD-824’s in your 4496, there will not be an
M•SYNC. In this case, a LAVRY ENGINEERING logo panel takes the place of the M•SYNC panel.

For A-to D Clocking Modes, there are three options:

-For Internal Clock operation set the far right switch on the M•SYNC to INT.

There are different types of “jitter” that can affect digital systems; some become part of the
recording and others don’t. Jitter in the A-to-D converter’s master clock can cause inaccuracies
that DO become part of the recording. Jitter in transmission from the converter to the device it is
feeding (a recording PC for example) DOES NOT become part of the recording. Therefore, Lavry
Engineering recommends that you operate A-to-D converters on “Internal Clock” if possible.

-For External Clock operation, set the far right switch on the M•SYNC to one of two external sync modes:

WRD CLK to lock the M•SYNC to an incoming external word clock signal. The lock condition
is indicated when the lock lamp illuminates.

AES to lock the M•SYNC to an incoming external AES Sync signal.
The lock condition is indicated when the lock lamp illuminates.

-The SYNC IN BNC connector is for feeding WORD CLOCK and AES SYNC signals to the M•SYNC.

-The SYNC OUT BNC connector is for supplying WORD CLOCK from the M•SYNC to external
devices.

-There is a 2X SWITCH on the M•SYNC rear panel near the BNC connectors. Select “ON” to enable the
unit to receive standard sync rates (42-50 kHz) while facilitating conversion at double speed (84-100
kHz). See External Clock Operation

-PLEASE NOTE: The M•SYNC is NOT internally terminated. See “Regarding Termination” under the
M•SYNC Specifications section (Page 6).

(below) for details.

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LavryBlue Operations Manual

2.) M•SYNC OPERATION

INTERNAL CLOCK OPERATION:

Set the right-hand switch on LavryBlue M•SYNC to “INT.”

The Narrow/Wide switch has no effect when the M•SYNC is set to “Internal” operation.
The “Lock" lamp does not illuminate during Internal Clock operation.

The 2 left switches set the sample frequency for Internal Clock and External Clock Narrow Mode.
The HIGH/LOW switch is set to High for 88.2 and 96 kHz, and to Low for 44.1 and 48 kHz.

SAMPLE RATE SWITCH POSITIONS:

Sample Rate-indicated by LED 48/96 - 44/88 Switch High – Low Switch

44.1 kHz Down Down
48 kHz Up Down

88.2 kHz Down Up
96 kHz Up Up

EXTERNAL CLOCK OPERATION:

Set the right-hand switch to “WRD CLK” or “AES.”

The unit locks to a signal applied to the rear panel BNC connector labeled “SYNC IN.”

-WRD CLK locks the M•SYNC to incoming word clock. When lock is achieved, it is indicated
by the LOCK lamp illuminating.

-AES locks the M•SYNC to an incoming AES signal. When lock is achieved, it is indicated by the
LOCK lamp illuminating.

The use of “AES BLACK” for AES Sync is recommended, whenever possible. This is an AES
signal with all of the audio data set to “0” or in other words “Mute.”

Setting the WIDE/NARROW
for standard sample rates: 44.1, 48, 88.2, & 96 kHz. In Narrow mode, the incoming Sync signal’s sample
rate MUST MATCH the settings of the M•SYNC to “Lock” (see Sample Rate Switch Positions- above, and
2X Switch- below).

Setting the WIDE/NARROW
clock operation in the 42-50 kHz range.

Setting the WIDE/NARROW
clock operation in the 84-100 kHz range. The rear panel 2X switch must be “OFF” for this configuration.

-When in NARROW lock, one frequency indicator lamp shows the selected output rate.

-When in WIDE lock and LOW, the top lamps (44.1 and 48 kHz) are lit simultaneously to
indicate 42-50 kHz range.

-When in WIDE lock and HIGH, the bottom lamps (88.2 and 96KHz) are lit simultaneously to
indicate 84-100 kHz range.

switch to NARROW provides a +/- 150 PPM lock range. Use this setting

switch to WIDE and the HIGH/LOW switch to LOW provides external

switch to WIDE, and the HIGH/LOW switch to HIGH provides external

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LavryBlue Operations Manual

(External Clock Operation-cont.)

-There is a 2X SWITCH on the rear panel near the BNC connectors. Set the 2X SWITCH to “ON” and
the M•SYNC’s HIGH/LOW switch to “HIGH” to enable the unit to receive standard sync rates while
facilitating conversion at double speed. This feature allows high-speed sampling in facilities without high­speed sync capability.
“2X” mode works in both narrow and wide lock. In NARROW mode this means sync signals of 44.1 or 48
kHz would allow AD operation at 88.2 or 96 kHz respectively. In WIDE mode this means a sync signal in
the range of 42-50 kHz will allow conversion at twice the frequency (84-100 kHz). The front panel lamps
indicate the AES output sample rate.
The 2X SWITCH “OFF” position requires the frequency of the external sync signal and M•SYNC sample
rate switch settings to match in Narrow Mode.

FOR EXAMPLE: if you have 48kHz external word clock source, the M•SYNC module can
generate a signal at 96kHz to clock the A-to-D converter(s) when the 2X Switch is “ON,” and the
M•SYNC’s switches are set to “48/96,” “High,” “Narrow,” and “Wrd Clk.”

3.) M•SYNC SPECIFICATIONS

INTERNAL CLOCK ACCURACY

+/- 25 ppm (parts per million)

NARROW MODE LOCK RANGE:

+/- 150 PPM for standard sample rates: 44.1, 48, 88.2, & 96 kHz.

WIDE MODE LOCK RANGE:

42-50 kHz range in “LOW”
84-100 kHz range in “HIGH”

SYNC INPUT:

The unit accepts an input sync signal at the rear panel BNC labeled “SYNC IN.”
This can be either a standard:
Sample rate WORD CLOCK “5V TTL level” (2.5V-5V amplitude)
or an AES SYNC SIGNAL (2.5V-5V amplitude).
The input IS NOT internally terminated- please see “Regarding Termination” (below).

SYNC OUTPUT:

The unit provides an output sync signal at the rear panel BNC labeled “SYNC OUT.” The signal is useful
for driving another LavryBlue 4496 system (for example a multi-channel application requiring more than 8
channels of A-to-D). The output clock is a 75-ohm back terminated 3V signal (compatible with the BNC
input of the next 4496 chassis and standard WORD CLOCK inputs).

REGARDING TERMINATION:

If the 4496 is the only unit being fed the Word Clock signal, connect the cable using a BNC "T" adapter
plugged into the “Sync In.” On the other side of the “T”, place a 75 Ohm BNC terminator connector. If the
Word Clock is “chained” using “T” connectors to other devices, be sure that there is a 75 Ohm terminator
on the “T” of the LAST device in the chain, and that none of the other devices have INTERNAL
TERMINATION. Alternately, if there is only ONE device with internal termination, it can be wired at the
“end of the chain” in place of the terminator. The important point is that there is only ONE termination and
it is located at the end of the chain.

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