Aphex 124B Level Matching Interface

Two Channel Audio Level Interface

The Model 124B 2-Channel Audio Level Interface from Aphex is designed to allow you to connect two channels of consumer-level, -10dBv gear to a professional-level, +4 or +8 dBm system. It provides a 2-way buffer so both systems connected can operate unaffected by the other. In addition, the 124B can also function as a line driver and a signal splitter.

Input
Servo-balancing means that high common mode voltages, such as induced hum from a nearby AC line, are compensated for, preserving headroom. The input impedance of 100 K Ω allows bridging over a 600 Ω balanced or unbalanced line with negligible loading effects. Front panel switchable 600 Ω load allows for input line termination when required

Outputs
Servo-balancing allows the outputs to be used balanced or unbalanced (single-ended) at any time by simply grounding either unused pin. The servo compensates for the voltage loss on one side so there is no 6 dB loss of level. The outputs are also protected against short-circuits, so nothing is damaged if the wrong pins are grounded. A front panel indicator will flash red when the balanced output level is 5 dB below clipping

Applications
Two-Way Interface Amplifier: for connecting any unbalanced device such as a cassette deck, equalizer, CD player or DAT deck to the IHF inputs and outputs. The balanced inputs and outputs go to a studio console, patchbay or other line level equipment. The different gains and impedances are matched for optimal performance

Line Driver: The servo-balanced input and output stages of the 124 can be used as a line driver for long lines. The output stage provides a short-circuit proof, low impedance source that will be relatively unaffected by the impedance of the cable. Gain may even be taken to boost signal level. In this application, either the unbalanced IHF or balanced high-level inputs may be used. For the latter, the IHF inputs and outputs are simply jumpered

Signal Splitter: The 124 may be used to provide two balanced outputs from a single unbalanced mono signal. A "Y" connector is used to split the incoming signal to each of the IHF unbalanced inputs

Features:

• Connects Consumer to Pro Level Gear
• -10dBv to +4/+8dBm
• 2-Way Buffer
• Stereo RCA & XLR Inputs & Outputs
• Line Driver & Signal Splitter Functions

Specifications:

• Audio
• Bandwidth: 5 Hz to 100 kHz (0, -0.5dB)
• Dynamic Range: 99 dB
• THD: 0.005
• Channel Isolation: > 70 dB
• CMRR: > 45 dB (typical)
• Input
• Connectors: IHF:2x RCA
• Balanced: 2x XLR 3-pin female
• Input Impedance: IHF: 18 kΩ
• Balanced: 100 kΩ with front panel 600 Ω termination switch
• Input Level: IHF: -10 dBV; peak 15 dBV (ref. 1 V)
• Balanced: +4 dBm (+8 dBm via internal jumpers); peak +30 dBm
• Output
• Connectors: IHF: 2x RCA
• Balanced: 2x XLR 3-pin male
• Output Impedance: IHF: 150 Ω
• Balanced: 65 Ω
• Output Level: IHF: -10 dBV, peak +18 dBV (ref. 1 V)
• Balanced: +4 dBm front panel adjustable +/- 6 dB, peak +25 dBm
• General
• Power Requirements: 100, 120, 220, OR 240 VAC, 50-60 Hz
• Dimensions (H x W x D): 1.75 x 8.25 x 7.25" (44.5 x 209.5 x 184.2 mm)
• Weight: 3.5 lb (1.6 kg)