MINDPRINT AN/DI PRO User Manual
Bedienungsanleitung
MANUAL
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MindPrint-AN/DI PRO
Dear Recording Specialist,
We are pleased that the MindPrint®AN/DI PRO is the tool of choice
in your quest for high-quality sound.
The AN/DI PRO is a stereo analog/digital converter designed specifically to meet the
discerning demands of professionals.Signals are converted at a resolution of 24 bits with a
dynamic range of up to 116 decibels.These impressive specs deliver excellent conversion
results,giving you the best possible signal to work with in subsequent audio processing
stages.What's more,whatever type of source signal you are dealing with—line or
microphone—the AN/DI PRO's high-end microphone preamps ensure that you end up with
a high-quality signal.With high sampling rates of up to 96 kHz,the device is ready today for
the digital technology of tomorrow.
Each of the engineers on the AN/DI PRO development team are specialists in their chosen
fields—audio,mixing consoles and digital technology.The AN/DI PRO is the product of all
their many years of experience and their insight into the needs of home and professional
recording.Over the past few years,modern recording equipment has achieved an extremely
high standard at ever more affordable prices.Unfortunately,the potential of high-definition
audio is rarely exploited to maximum benefit—poor quality input signals and deficient
converters give processing gear inadequate raw material to work with.
The AN/DI PRO remedies this very problem.It empowers you to make the most of your skills
and your recording equipment’s potential. You'll be amazed at the difference - your tracks
will sound more vivid,more truly natural and,above all,more musical.
St.Wendel,June 1999
MindPrint-AN/DI PRO
1.Layout of the AN/DI PRO
1.1 Input Section
The AN/DI PRO is equipped with a complete input section comprising a studio-level line
input,a microphone input with a -20 dB damping switch,and switchable phantom power
for condenser microphones. The discrete microphone input stage features Class-A
engineering and delivers the finest high-end quality for professional applications.
With its sensibly arrayed front panel inputs, the AN/DI PRO is a highly versatile converter,
a universal tool that enables you work with any type of signal source and is therefore
ideally suited to every project studio.
The input section actually consists of two independent circuits,which allows you to
handle and process the two stereo channels separately.With the benefit of these dual
circuits,you are free to use the AN/DI PRO for stereo signals as well as two separate
monaural channels.
The Mic/Line input selector switches back and forth between the microphone and line
input.Separate gain knobs for the microphone and the line signals allow you to set a
suitable level for each.The 12-segment LED meter is a visual reference that will make it
easier for you to set the ideal level.For some applications,you may find that its "hotswap" option comes in handy when you have to switch back and forth repeatedly between
the two inputs while the device is in operation.With separate knobs for mic and line,you
are spared the hassle of constantly having to readjust levels.
If you connect dynamic or electret microphones,you won't need phantom power. However,
the first choice in studios are generally condenser microphones that require 48 volts in
accordance with the international norm IEC 268-15. The AN/DI PRO is designed to provide
the required current. For microphones that need it,simply press the V 48 switch.When
you're recording particularly loud instruments,for example a kick drum or a trumpet with
the mic pointing directly at its horn,you may come across a situation where you are
unable to turn the level down far enough to get a clean signal.The AN/DI PRO features a
- 20 dB damping option specifically for this situation.
1.2 Level Meter
In contrast to analog gear, digital devices aren't designed to accommodate saturated
signals.Up to the final tenth of a decibel under the clip threshold,the sound remains
unchanged,but as soon as the signal level crosses this threshold,the device will
immediately generate extremely ugly distortion—universally dreaded digital clipping.
On the other hand,if you dial in a level that is too low,this inevitably causes the level of
quantization noise to increase.This type of noise is generated when the signal is digitized.
During the quantization process, an infinite or continuous analog signal is subdivided into
a finite number of discrete digital values.Historically, this problem has made it rather
difficult to dial in a suitable level on a conventional A/D converter.
It is essential that a kind of buffer,or headroom,be maintained to prevent the signal from
crossing the clipping threshold. At the same time, however,this headroom has to be kept
as small as possible in order to hold quantization noise to a low level.
These two critical prerequisites are much easier to meet - with the AN/DI PRO's 24-bit
technology and superior dynamic range of up to 116 dB - because the ratio of the clipping
threshold to quantization noise is considerably greater than is the case
with conventional converters.
In addition,the level meter is designed to let you set levels as you did in the past on
standard analog gear—you aren't forced to grow accustomed to a new technique. Simply
set your AN/DI PRO to the usual 0 dB mark—brief signal peaks that bleed into the
yellow zone are OK.When you dial in this type of setting,you automatically have a
fairly comfortable headroom of 8 decibels and a signal-to-noise ratio of
a whopping 108 decibels.
As wonderful as the AN/DI PRO is,it is nevertheless subject to the laws of physics,so
avoid clipping like the plague.Make certain that the final LED segment (red) never lights
up,not even in response to spikes or extreme signal peaks.
1.3 A/D Converter
After the AN/DI PRO’s premium preamp section has worked its audio magic, the signal is
converted so that it can be introduced into the digital domain.The converted signal is
routed out simultaneously via the three digital outputs located on the rear panel of the
device — not surprisingly, these are labeled Digital Out. If you want to patch the stereo
channels' signals to your other digital equipment further down the line,you can access
the AES/EBU signal at the XLR port or you can access the S/PDIF signal at either the
coaxial port or the optical interface.What's more,this is not just an either/or
proposition—you are free to use all of the outputs at the same time. The word length of
the digital signal is 24 bits and thus fully exploits the technical potential of the AES/EBU
and S/PDIF standards right down to the last bit.For your sampling frequency, you can
choose from the standard 44.1 and 48 kHz settings, plus the state-of-the-art 96 kHz format,
which is well on its way to becoming the standard for professional recording. Use the
front panel selector buttons to set the device to the same sampling rate that the rest of
your post-converter digital equipment will be using.Using external synchronization the
AN/DI PRO also allows you to use sampling frequencies of 32 and 88.2 kHz.64 kHz
sampling frequency is not possible.
1.4 Inserts
The AN/DI PRO offers every opportunity to transport any signal into the digital domain,
totally unadulterated and in first-rate quality, thus enabling digital signal processing of
the highest order. There may be times,however,when you want to deliberately color an
audio signal or process it via analog gear.For example,you may choose to route the
master mix through a high-end analog compressor or add a touch of tube enhancement to a
signal before you send it to a hard-disk recorder.The best place within the signal chain to
insert this type of equipment is after the preamp,but before the analog signal is
transformed into its digital equivalent.
The AN/DI PRO is equipped with Send and Return jacks that enable you to insert analog
devices such as equalizers,compressors or tube devices. Connect the input of the external
device with the Send jack of the AN/DI PRO,and route the processed output signal to
AN/DI’s Return jack.This means you can still fall back on your favorite analog
processor—it simply becomes a component of the signal chain,the final stage of which
is digital conversion in outstanding quality.
1.5 Synchronization
Whenever digital audio devices are connected to one another,their internal clock
frequencies (sampling rates) need to run in sync.If the digital signal is being transmitted
between two and only two devices,you won't have to concern yourself with this necessity
because the signal formats AES/EBU and S/PDIF transmit synchronization information
along with the audio data.Here the first device dictates the conditions for communication
to the second.The receiving device automatically adapts its sampling rate to match that of
the sending device by tracking it via a control circuit (PLL,Phase Locked Loop).
If you intend to use your AN/DI PRO either as the front-end device for computer-based
hard-disk recording,as a high-quality preamp for live recording in conjunction with a
24-bit DAT recorder,or as a master converter for your analog mixing console,you don't
need to give synchronization another thought.
If,however,your setup features more than two digital devices, automatic synchronization
may be hampered by too long a chain of consecutive devices or—in complex configurations in which some devices simultaneously send and receive data— automatic
synchronization may be altogether impossible.Synchronization errors are manifested as
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