Used RME ADI-8 Pro, 8 Channel AD / DA 24 bit, 44.1/48 kHz converter.  While I've owned it for over a decade cosmetically it is in good shape (see pics), inevitable 'rash' from rack mounting.  Never experienced any issues with its performance.  Initially used it as 'the' converter in the project studio, as those were upgraded used it as 'the' interface with outside PT operations.  Gradually it found it's primary use in the rig for recording live shows.  Most recently it rotated back to the home studio as backup for A/D conversion for a lunchbox or with an 8 channel small format console.  Selling at this time as I just picked up a new (to me) vocal mic and recently migrated to RME's UFX (Took so long to move to UFX because my installed base of RME gear simply worked so well that it hardly seemed to worth the change)RME ADI-8 Pro
SyncAlign
SyncCheck
Intelligent Clock Control
Hi-Precision 24 Bit / 48 kHz
8 Channel AD / DA-Converter
ADAT® optical / TDIF®-1 Interface
Digital 24 Bit Interface / Format ConverterThe ADI-8 DS is an 8-channel analog to digital and digital to analog converter in a 19" rackmount
enclosure of 1 U height. 24 bit / 96 kHz converters offer 117 dBA dynamic ratio. Servo balanced analog inputs and outputs are fitted with both D-sub and 1/4" TRS jacks. The signal path from the jacks to the ADC is totally balanced. Both signal paths A/D and D/A are internally DC-coupled, for highest phase accuracy at lowest rolloff.The digital inputs and outputs are available as ADAT optical and TDIF-1 connectors.The AD-converter can provide several internal clocks (44.1, 48, 88.2 kHz, 96 kHz).  The ADI can serve as the master via Word Clock, ADAT or TDIF.  It can be synchronized via these same protocols to external sources. The current state of locking and clock synchronisation is shown by blinking or constant lit LEDs.Technical Specifications
·  Power supply: Internal, 100-240 V AC, 30 Watts
·  Dimensions 483 x 44 x 205 mm
·  Weight: 2 kgAnalog Specs
AD
·  Resolution AD: 24 bit
·  Signal to Noise ratio: 112 dB RMS unweighted, 116 dBA
·  THD: < -110 dB, < 0.00032 %
·  THD+N: < -102 dB, < 0.0008 %
·  Crosstalk: > 130 dB
·  Maximum input level AD: +19 dBu
·  Frequency response AD, -0.1 dB: 5 Hz – 21.5 kHz
·  Input Line: 1/4" TRS and 25 pin D-sub, servo balanced
·  Input impedance Line: 10 kOhm
·  Input sensitivity switchable: +4 dBu, -10 dBV, Hi Gain
·  Input level for 0 dBFS @ Lo Gain: +19 dBu / -1 dBV
·  Input level for 0 dBFS @ +4 dBu: +13 dBu
·  Input level for 0 dBFS @ -10 dBV: +2 dBVDA
·  Resolution DA: 24 Bit
·  Dynamic Range: 112 dBA (unmuted)
·  THD: < -104 dB, < 0.00063 %
·  THD+N: < -102 dB, < 0.0008 %
·  Crosstalk: > 110 dB
·  Maximum output level DA: +19 dBu
·  Frequency response DA, -0.1 dB: 5 Hz – 21.6 kHz
·  Output Line: 1/4" TRS and 25 pin D-sub, servo balanced
·  Output impedance Line: 47 Ohm
·  Output level switchable: Hi Gain, +4 dBu, -10 dBV
·  Output level at 0 dBFS @ Hi Gain: +19 dBu
·  Output level at 0 dBFS @ +4 dBu: +13 dBu
·  Output level at 0 dBFS @ -10 dBV: +2 dBVDigital Specs
·  Super Low Jitter Design: < 4 ns word clock PLL, < 1 ns ADAT PLL, < 1 ns internal
·  Internal sample rates: 44.1 kHz, 48 kHz
·  Supported sample rates through word clock in: 27 kHz - 57 kHz
·  Internal resolution: 24 bit
·  Outputs: ADAT optical (24 bit), TDIF-1 (24 bit), word clock
·  Inputs: ADAT optical (24 bit), TDIF-1 (24 bit), word clock
·  Supported sample rates through ADAT In: 33 kHz - 57 kHz
·  Bit Split: 24 bit to 1 channel 16 bit and 1 channel 8 bit