664 Specs:

Frequency Response
20 Hz to 50 kHz, ± 0.5 dB

THD + Noise
0.09% max (50 kHz, +18 dBu at line out, fade fully up)

Equivalent Input Noise
-126 dBu (-128 dBV) maximum. (22 Hz – 22 kHz bandwidth, flat filter, trim control fully up)

Inputs
XLR Mic: active-balanced for use with ≤600 ohm mics, 4k ohm actual; 12V or 48V phantom power, 10 mA max

XLR AES: AES3 or AES42 (10 V power), SRC

XLR Line: active-balanced for use with ≤2k ohm outputs, 10k ohm actual

TA3 Line (7-12): active-balanced for use with ≤2k ohm outputs, 10k ohm actual

RTN A, B, C (3.5 mm/10-pin): unbalanced stereo for use with ≤2k ohm outputs, 30k ohm actual

Maximum Input Level
XLR Mic: 0 dBu (0.78 Vrms)

XLR Line: +40 dBu (80 Vrms)

RTN A, B, C (3.5 mm/Multi-pin): +24 dBu (12.4 Vrms)

High-Pass Filters
Sweepable 80 Hz to 240 Hz, 12 dB/oct at 80 Hz, 6 dB/octave at 240 Hz

Input Limiters
Individual limiters on both trim and fader stages, +16 dBu threshold, 20:1 limiting ratio, 1 mS attack time, 500 mS release time

Link I/O
Unbalanced stereo for linking to MixPre, 302, 442, 552, and 664; 2k ohm impedance

Maximum Gain
Mic-In-to-Line-Out: 93 dB

Mic-In-to-Aux-Out, -10 Out: 79 dB

Line-In-to-Line-Out: 39 dB

Output Type
Line: transformer-balanced for use with >=600 ohm inputs, 100 ohms

-10: transformer-balanced for use with >=10k ohm inputs, 3.2k ohm

Mic: transformer-balanced for use with >=600 ohm inputs, 150 ohms

TA3 Mic/Line: active-balanced, pin-2 and 3 driven, for use with >=3k ohm inputs, 1k ohm

TA3 Direct Outs Mic/Line: active-balanced, pin-2 and 3 driven, use with >=3k ohm inputs, 1k ohm

Tape Outs (3.5 mm and TA3-type): unbalanced, stereo, use with >=6k ohm input, 1.8k ohm actual

Headphones (3.5 mm and 1/4"): unbalanced, stereo, use with 8-2k ohm headphones, 50 ohms

Line Output Clipping Level
(1% THD) 20 dBu minimum with 10k load

Maximum Output Level
Line: +20 dBu (7.8 Vrms)

-10: +6 dBu (1.5 V rms)

Mic: -20 dBu (0.078 Vrms)

Tape Outs: +6 dBu (1.5 Vrms)

Output Limiters
Affects analog output. Threshold selectable from +4 dBu to +20 dBu, 1 dB steps, 20:1 limiting ratio, 1 mS attack time, 500 mS release time.

Recording Tracks
16 tracks (12 inputs, 4 output buses), monophonic or polyphonic Broadcast WAV or timecode-stamped MP3

A/D
24-bit, 114 dB, A-weighted dynamic range typical; 44.1 kHz, 47.952 kHz, 48 kHz, 48.048 kHz SR

Digital Outputs
AES3 transformer-balanced, in pairs; 1-2 XLR-L, 3-4 XLR-R, 5-6, multi-pin 1, 7-8, multi-pin 2, 110 ohm, 2 V p-p, AES and S/PDIF compatible

Recording Storage Type
SDHC, SD, SDXC – exFAT for cards >32 GB, FAT32 for <32 GB; CompactFlash (CF) FAT32, will format memory cards in unit

Sample/Timecode Accuracy
± 0.2 ppm (0.5 frames per 24 hours)

Timecode and Sync
Modes Supported: off, Rec Run, Free Run, 24h Run, External

Frame Rates: 23.976, 24, 25, 29.97DF, 29.97ND, 30DF, 30ND

Accuracy: Ambient generator, 0.5 frame in 24 hr

Time Code Input: 20k ohm impedance, 0.3 V – 3.0 V p-p (-17 dBu – +3 dBu)

Time Code Output: 1k ohm impedance, 3.0V p-p (+12 dBu)

Word In/Out: square wave; 10k/75 ohm, 1-5V p-p input; 75 ohm, 3.3V p-p output, at SR

Power
External: isolated 10-18 V on locking 4-pin Hirose connector, pin-4 = (+), pin-1 = (-).

Internal: accepts five (5) NiMH, 1.5V Lithium, or Alkaline AA batteries. Note that run time will be very limited when using Alkaline batteries (30 minutes to one hour depending on settings). NiMH or Lithium batteries are the preferred type because of the approximate 2x to 4x run time compared to Alkalines.

Environmental
Operating: -20°C to 60°C, 0 to 90% relative humidity; (non-condensing) Storage: -40°C to 85°C

Dimensions and Weight
Dimensions: 5.3 cm x 32 cm x 19.8 cm (H x W x D) 2.1" x 12.6" x 7.8"

Weight: 4 lbs. 12 oz. (unpackaged, without batteries)