I recently purchased a breakout cable from Trew Audio for the 788T.It has 4 digital in's(xlr 110 ohm)and 1 digital out(5&6)which can be switched internally on the 788T.Here is some info from the revised user guide.
AES42 Digital Microphones
The 788T is compatible with digital microphones conforming to the AES42 specification, such as the
Schoeps CMD-2U. By setting DIGITAL INPUT: AES42 POWER to Enabled, the 788T supplies +10V
of “digital phantom power” to each of the digital inputs. The gain of the microphone can be adjusted
with the 788T’s front panel gain control just like a normal analog microphone. The gain adjustment is
controlled in the 788T digital domain.
Never apply digital phantom to unbalanced digital inputs, as this can result in damage to the hardware.
The 788T can lock its sample clock to a single AES42 digital microphone signal. This is set from the
Setup Menu option REC: SYNC REFERENCE to the corresponding digital inputs. When the 788T is
set to use its internal clock any connected incoming AES3 or AES42 signal is sample rate converted.
Things to consider when using AES42:
• The 788T supports four AES42 pairs.
• Input Limiters can not be enabled for Digital Inputs.
• The 788T supports AES42 Mode 1 operation, Mode 2 operation is not supported. In other
words, the 788T supports digital audio transfer via AES42. However, it does not support the
AES42 protocol for remote control, microphone identification, or status flag indicators. Mode 2
microphones will automatically operate in Mode 1 when connected to the 788T.
• When using multiple AES42 microphones set the REC: SYNC REFERENCE to Internal. This
will ensure a synchronous operation between the 788T and digital microphones.
Page 9-user guide
5) Multi-Function DE-15 Connector
Multi-function DE-15 connector acts as
AES3 Inputs 1-8, AES3 Outputs 5-6, and
Logic In and Out. Analog and digital
inputs can be used simultaneously. See
Connector Pin Assignments.
Sample Rate Converters are enabled
on each AES input when Setup Menu
REC: SYNC SOURCE is set to Internal.
See Sample Rate Converterts.
AES inputs support AES42 Mode 1 oper-
ation, supplies +10 V of digital phantom
power. See AES42 Digital Microphone
page 34
Internal
The 788T disregards any external sync source and sample clocks are internally generated. When set
to Internal, the Sample Rate Converters will be applied to any incoming AES signal.
Sample Rate Converters
The 788T has high-quality, hardware sample rate converters (SRCs) on each of its AES/EBU digital
inputs. The SRCs apply to AES signals when the Setup Menu option REC: SYNC REFERENCE is set
to Internal. The 788T’s digital inputs accept AES signals with sampling rates from 32 kHz to 192 kHz.
With the sample rate converters each digital input can be fed with signals of any sample rate without
having to word clock all of the devices together.
The SRCs are only active when needed; when not needed they are deactivated. To use digital inputs
without the SRCs active, set the REC: SYNC REFERENCE Word Clock Input, Video Input, or to an
AES input pair.
Info from Sound Devices Support webpage.
AES 42 Support in 788T
Sound Devices introduces AES 42 digital microphone support in the 788T with firmware revision 1.5 beta. AES 42 is a protocol for direct digital interconnection between microphones and devices, such as mixers and recorders.
Why AES 42?
One benefit of AES 42 argued by microphone manufacturers is that by digitizing the signal at the capsule, several analog gain stages are eliminated. Theoretically, conversion at capsule-level improves signal transfer and can result in higher dynamic range. With a digital signal in the microphone, the mic can have on-board digital signal processing (DSP) to perform numerous functions including: gain control, frequency-domain adjustments such as high-pass filters, and dynamics control such as compression/limiting.
AES 42 and Word Clock
The 788T provides support and connectivity for Mode 1 (asynchronous) connections. Mode 1 uses the microphone’s own clock generator for its word-clock-source. Because the word-clock-signal out of the microphone may differ from the recorder’s set sampling rate, the 788T’s hardware sampling rate converter (SRC) is activated for AES 42 inputs when using the recorder’s word clock. The recorder provides connection for multiple (up to four) AES 42 input sources at any supported sampling rate. The 788T accommodates AES 42 (and AES3) inputs with sampling rates from 32 kHz to 192 kHz.
Connectivity and Gain
The 788T provides “digital phantom power” for AES 42 microphone operation. Similar to a balanced, analog microphone connection, AES 42 requires two-conductors and a shield. An AES 42 microphone signal appears on both “sides” of a connected input pair. For example, when connecting an AES 42 microphone to AES pair 1/2, the microphone signal appears at both input 1 and input 2.
When an AES 42 microphone is connected to the 788T, the recorder’s front panel gain controls digital gain levels in the recorder, not digital gain in the microphone and not analog levels.
Unsupported AES42 Features
The AES42 protocol includes several modes of microphone control and connection. The 788T presently does not support the following:
Mode 2, the 788T does not send word clock signals to AES42 microphones nor does it send control signals to control…
in-microphone digital gain, gain is controlled after the microphone’s digital gain stage,
DSP control, the 788T does not control AES42 DSP processing.
Is AES 42 Relevant?
As AES 42 hardware becomes available from manufacturers such as Neumann, Schoeps, and Sennheiser, Sound Devices will evaluate its application in mixers and recorders. The identified benefits of AES 42 appear real for some applications. Whether they prove to be a demonstrable for field production remains to be seen.
So if I got 4 Schoeps CMD-2U bodies,one pair for the MK41's>KC-5 and another pair for the MK22's>KC-5 this would work for a 4 channel recording?I also read that while the digital mics are running I would still be able to run all 8 analog channels as well?
Here is a link to the revised user guide:
http://www.sounddevices.com/download/guides/788t_en.pdfSchoeps link to CMD-2U:
http://www.schoeps.de/E-2004/cmd2.htmlSound Devices AES 42 support:
http://www.sounddevices.com/notes/recorders/788/aes-42-support-in-788t/