Aphex Model 1788A

Aphex 1788A 8-channel Microphone Preamp with Optional Remote Control and Digital

The Aphex 1788A 8-channel Preamp is a 2U rackspace pre for stage or studio. The idea behind the 1788A is that even with balanced cable runs, mics sound better when the signal doesn't have to travel great distances to get where it's going. Aphex believes that by coupling the 1788A with the optional 1788ARC remote control will give you the shortest cable runs possible and dramatically improve the sound quality.

Aphex 1788A At a Glance:

• Easily transported size

• Microphone output limiter
• Adjustable maximum output level
• Separate analog outputs

The Model 1788A contains eight preamps in 2RU space. Since there is a fair amount of heat dissipation, there should be at least 1RU spacing between every preamp. In that configuration, they may be stacked to provide 40 channels of high-quality preamps in a standard 16RU road case.

All preamps have a maximum input level. Once that level is exceeded, there is no way to remove that very unpleasant distortion. To avoid that occurrence, many engineers set the preamp, so the expected peak level at maximum sound level is still at least 12dB below the clip point. While this provides some insurance against the preamp clipping, it causes a loss of noise performance and, in the case of digital, a loss of resolution. The Model 1788A has a unique limiter (patent pending) in the front end of the preamp, which limits the output level of the microphone by as much as 20dB. Hence the name, Microphone Output Limiter. This allows the engineer to get maximum noise performance and also allows maximum resolution for an analog to digital converter, all without worrying about crashing the preamp. The Model 1788A has 39dB of adjustable input gain and fixed gain of 26dB for a total maximum gain of 65dB. The 26dB pad allows a preamp to be run as a unity gain buffer stage. For example, this allows the line-level output of a wireless mic receiver to be fed into the preamp.

The maximum output level of the Model 1788A is +24dBm (loaded into 600 ohms) balanced. There are, however, many input stages which have odd maximum input levels (e.g. -+18dBu). To retain the function of the microphone limiter and maximize noise performance of the entire audio system, the Model 1788A has output level trim of up to 24dB. Once the maximum input level of the device following the Model 1788A is defined, the output level of the 1788A can be trimmed to that exact level. The input gain of the 1788A is then adjusted to achieve optimum performance. In addition to the 24dB of output adjustment, each output may be muted.

Microphones are often passively split and then fed to two or more locations. The Model 1788A has two separately trimmable, buffered analog outputs. The main output on XLR is transformerless servo-balanced, and the second output is tranformerless balanced on a DB-25 multi-pin connector. This allows two separate inputs to be fed at optimal levels from an optimized mic preamp.

The Aphex Model 1788A provides eight preamps in 2RU space. All of its settings are remotely controllable via Ethernet or MIDI, using Aphex's hardware remote or on PC or Mac using the company's 1788ASW control software. The 1788A features Aphex's proprietary MicLim technology, a unique, patented limiter in the front end of the preamp which limits the output of the microphone by as much as 20dB. It has two separately trimmable, buffered analog outputs, as well as optional digital outputs (AES/EBU, TDIF, and ADAT) with selectable sampling rates up to 96kHz. LNA, the 1788A's digitally controlled Low Noise Amplifier, allows its input gain to be adjusted in 0.125dB steps and 1-dB stops without noise or glitches. There is also an optional digital output module, the 1788A-1, available with AES/EBU, TDIF, and ADAT outputs at 24-bit/44.1, 48, and 96kHz (AES only).

Aphex 1788A Features:

• 2U rackspace

• 8 channels
• Microphone output limiter
• Adjustable microphone output
• Separate analog output
• Up to 40 channels of I/O can be stored in a 16U rack
• Optional remote control available
• Optional digital output module also available
• 24-bit
• 44.1-96khz
• Ultra-low noise operation
• 1788A preamp is now controllable via Pro Tools and Mac!
• Perfect for FOH or studio engineers