Operating instructions

7.2 Electronics (Measured with AMPEX #456 Tape)
Line Input Transformerless Active Balanced (Floating transformers are optional)
Input Impedance: 10 kΩ (20 Hz to 20 kHz)
Nominal Level: +4 dBu
Connectors: XL-3 type, Female
Line Output Transformerless Active Balanced (Floating transformers are optional)
Output Impedance: 5 Ω (20 Hz to 20 kHz)
Load impedance: min. 150 Ω
Nominal Level: +4 dBu
Balanced/Unbalanced switchable
Connectors: XL-3 type, Male
Amplifier Clipping +28 dBu
Headroom 24 dB
Equalization 30 ips: AES
15 & 7.5 ips: NAB or IEC (CCIR), switchable
Record EQ to be specified at time of order.
Punch In/Punch Out Gapless and noiseless inserts with automatic monitor switching.
Standard Record Level 320 nanoWebers per meter (nWb/m).
Frequency Response Rec/Rep 30 ips: 50 Hz to 22 kHz + 2 dB, -3 dB (0 VU)
15 ips: 30 Hz to 20 kHz + 2 dB, -3 dB (0 VU)
7.5 ips: 30 Hz to 16 kHz + 2 dB, -3 dB (-10 VU)
Rec/Sel·Rep 30 ips: 50 Hz to 16 kHz ± 3 dB (0 VU)
15 ips: 30 Hz to 16 kHz ± 3 dB (0 VU)
7.5 ips: 30 Hz to 12 kHz ± 3 dB (-10 VU)
Distortion max. 0.5% THD at 1 kHz, 320 nWb/m.
Crosstalk 24 track: 1 kHz, min. 55 dB
16 track: 1 kHz, min. 58 dB
8 track: 1 kHz, min. 58 dB
16 and 24 track: 200 Hz to 16 kHz, min. 43 dB
Erase Efficiency min. 75 dB at 1 kHz
Signal-to-Noise Ratio (Rec Level: 1040 nWb/m)
UNWTD* ANSI “A” DIN 45405 audio
MTR-90III-8 & 16 AES 30 ips 72 dB 74 dB 71 dB
IEC 15 ips 71 dB 73 dB 69 dB
7.5 ips 68 dB 70 dB 66 dB
NAB 15 ips 69 dB 71 dB 67 dB
7.5 ips 71 dB 73 dB 69 dB
MTR-90III-24 AES 30 ips 70 dB 73 dB 70 dB
IEC 15 ips 69 dB 71 dB 67 dB
7.5 ips 66 dB 68 dB 64 dB
NAB 15 ips 67 dB 69 dB 65 dB
7.5 ips 69 dB 71 dB 67 dB
(*measured through 30 Hz to 18 kHz audio filter)
Reference Fluxivity NAB: 250 nWb/m
IEC: "320" nWb/m
Figures enclosed in quotations (" ") represent values for open circuit fluxivity.
Bias Frequency 257 kHz
Erase Frequency 86 kHz
MTR-90III Operation and Maintenance Manual
October 1990
Section 7 Specifications
7 - 3