8 channel Mic/Line A/D module with Direct Out, up to 192 kHz Merging

As with the previous cards, Direct Analog Out connections are present to allow a mic level feed to be sent to an analog mixer or recorder. The RAVENNA/AES67 connection on Horus and Hapi allows for full remote control of all parameters including the ability to switch individual channels to Mic or Line. Phantom power switching, phase reversal, and low cut filters can be enabled from the control room or locally from the front panel of the unit.

Merging’s team of engineers has redesigned these circuits using the latest components and achieving remarkable transparency and performance. A dynamic range of better than 120dB is easily achieved. The input stage now features the ability to select the optimal impedance for condenser or dynamic microphones and this can also be done on a per-channel basis. In order to improve any leakage induced noise from the phantom power during warm-up, lower value, higher voltage high grade electrolytic capacitors have been used. Particular care has been taken to minimise any DC offset to the inputs of the A/D converter. This improvement to the DC servo loop guarantees that the offset is under 1mV over the whole gain range up to a maximum of 66dB. Analog detection that is a feature of the ADA8 cards is now incorporated to ensure that gains are switched near to zero. Both these features combine to suppress any clicks caused by switching the gain settings.

In summary, the AKD8D/P offers ultra-low distortion and noise floor at low levels whilst reducing latency even more. Another remarkable feature of the Merging Audio Interfaces is the low power consumption. The new components reduce that further by saving over 2 Watts per board which could be as much as 12 Watts on a fully loaded Horus.

Mic Pre-Amp + ADC

• Mic Pre Max Input (Pad On / Pad Off): +24 dBu / +13 dBu
• Input Impedance (Differential, Software Switchable Per Channel): 1.9 kΩ / 10 kΩ
• Input Impedance with +48V ON (Diff., Soft. Switchable Per Channel): 1.9 kΩ / 10 kΩ
• Dynamic Range (A-weighted, typ.) , ref +10 dBu: 123.5 dB
• Gain Range (software controlled): 0 dB to +66 dB
• Gain Step/Precision: 0.5 dB / ±0.2 dB
• THD+N Pre + A/D (20 Hz-20 kHz) @ -2 dBFS (AD8/AD8P): < -110dB (0.00031%)/-111dB (0.00028%)
• Interchannel Crosstalk @ 1kHz, typ.: < -125 dB
• EIN @ >40 dB Gain (150Ω Source Impedance, A-weighted, typ.): < -128 dBu
• Common Mode Rejection Rate (20 Hz – 20 kHz): > 60 dB (up to 0 dBFS)
• Phantom Power (Software Switchable Per Channel): +48V
• Phase Reverse (Software Switchable Per Channel): YES
• Low Cut filter (Software Switchable Per Channel): -12 dB/octave, 80 Hz

Line Input

• Max Line Input for 0 dBFS: +24 dBu
• Input Impedance (Differential): 10 kΩ
• Dynamic Range (A-weighted, typ), ref +24 dBu: 124 dB
• THD+N Line+A/D (20 Hz - 20 kHz) @ -10 dBFS: < -110dB (0.00031%)/-111dB (0.00028%)
• Interchannel Crosstalk @ 1kHz @ fullscale: < -130 dB
• Sensitivity Range for 0 dBFS (software controlled): -42 dBu to +24 dBu
• Gain Step/Precision: 0.5 dB / ±0.2 dB
• Common Mode Rejection Rate (20 Hz – 20 kHz): > 60 dB / > 65dB (both up to 0 dBFS)
• Connector Pinout: DB-25 / AES59 (Tascam Ana.)