User Guide

dCS Purcell User Manual Manual for Software Issue 2.2x
dCS Ltd September 2004
Manual filename: Purcell Manual v2.2x.doc Page 23 email: [e-mail]
English version web-site: www.dcsltd.co.uk
1394 ID
1394 ID1394 ID
1394 ID – 1394 Source Identification
This page sets a number between 1 and 8 to identify each Purcell you have
connected to the 1394 system.
do this: Open the Menu and step through until the display shows 1394ID:x, where x is a
number between 0 and 8.
do this: Press the
Select button repeatedly, allowing the unit to settle for a few seconds
each time. The display cycles through 1394ID:0, 1394ID:1, ......., 1394ID:7,
1394ID:8, and back to 1394ID:0.
If you set 1394ID:2 for example, when the DAC is selected to this Purcell, it will
display Purcell 2. You can set any other Purcells connected to the 1394 system
to a different number. If you set 1394ID:0, the DAC displays Purcell, without a
number.
Out Word
Out WordOut Word
Out Word – Output Wordlength
The Output Wordlength should be set to match the maximum wordlength that
the DAC you are using can accept. If you are not sure what this is, please
consult the manufacturer or your dealer. For the dCS Elgar Plus or Delius, this is
24 bits. Purcell will work best with DACs that can accept 24 bits. Note that for
176.4 or 192kS/s output sample rates, this setting cannot be changed – 24 bits
output wordlength is selected automatically.
do this: Open the Menu and step through until the display shows Out Word.
do this: Press the
Select button once.
Assuming for this example that the current Out Word setting is 24 bits, the
display will change to Out :24.
do this: Press the
Select button slowly five times and the display will show in turn:
Out :22, Out :20, Out :18, Out :16 and finally Out :24.
do this: Choose the setting that matches your DAC.
The unit stores two wordlength settings: - the last one used when upsampling
and the last one used when downsampling. These settings are automatically
applied when you change between upsampling and downsampling to help avoid
mistakes.
IMPORTANT! If Out Word is set to less than 24 bits, the 24bit indicator in the status
indicator block will turn off. This warns that you need to set Purcell to apply
some Noise Shaping and / or Dither to smooth out the response.
Use Table 1 below to determine the appropriate Noise Shaping and Dither
settings for the Output Wordlength that you have selected.
Out Word
Out WordOut Word
Out Word N.Sha
p
e
N.Sha
p
eN.Sha
p
e
N.Sha
p
e Dithe
r
DitherDithe
r
Dither
24 bits
→
Auto & Off
22 bits
→
1
st
or 3
rd
/ Triangle
20 bits
→
1
st
or 3
rd
/ Triangle
18 bits
→
3
rd
or 9
th
&N.Tri
16 bits
→
9
th
&N.Tri
Table 1 – Recommended Output Wordlength, Noise Shaping and Dither Settings
For more information, please see “Wordlength Reduction” on page 52.