HD MIC-PRE Operating Manual
Fredenstein HD Microphone Preamplifier The Fredenstein HD microphone preamplifier utilizes a completely new approach to microphone level amplification. Everybody in the recording industry is now using 96 kHz or 192 kHz sampling rates while tracking, but still using equipment, which cannot provide the frequency response or bandwidth provided by modern A/D converters. The HD Pre overcomes these limitations and yields a new sound quality.
Fredenstein HD Microphone Preamplifier Volts per microsecond. Figure 2: 106 kHz square wave response The input impedance of the HD Pre is standard 200 kOhms and can be reduced to 1 KOhm by activating the LOW-Z function. This high input impedance avoids loading the microphone output transformers and yields in most cases sonically superior result. In any case, the engineer can switch between the two settings to find the desired result without any fear of damaging the microphone.
Fredenstein HD Microphone Preamplifier Figure 3: Frequency response Figure 4: Total Harmonic Distortion plus Noise at 64 dB Gain The output reference level is + 4dBu, the standard American studio reference level. So THD plus Noise is at -71 dB at 64 dB gain which equals to an input noise of -135 dB at 50 Ohms generator output impedance. The total distortion and noise ratio is excellent at 0.0082 %. Fredenstein HD Pre Manual V1.
Fredenstein HD Microphone Preamplifier Figure 5: Total Harmonic Distortion (THD) plus Noise at 31dB Gain Overview: Fredenstein HD Pre Manual V1.
Fredenstein HD Microphone Preamplifier Rotary Control: GAIN : Upper Gain Switch from 22 to 40 dB in 3dB steps and enable for Lower Gain Switch Lower Gain Switch from 43 to 64 dB in 3 dB steps Output Peak Level Indicator: -30 dB to +20 dB (0dB = +4dBu) Switches: POL PAD LOW Z : : : P48 Low Cut : : DI : Fredenstein HD Pre Manual V1.
Fredenstein HD Microphone Preamplifier Installation: Please power down your rack or box first before inserting the HD Pre. The power requirements are quite demanding at a maximum of +/-150mA and the HD Pre will not work in weaker racks. Gain Control: Two Stage Gain Control, ranging from 22 to 64 dB in 15 steps, 3 dB each. The upper rotary switch covers the range from 22 to 40 dB, the lower switch from 43 to 64 dB. The clockwise last position of the upper switch, labeled Link, enables the lower switch.
Fredenstein HD Microphone Preamplifier Technical Data: Frequency Response : Distortion : Input Noise : Input Impedance : DI Impedance : Max. Input Level : PAD attenuation : Output Impedance : Max. Output Level : Max Input Signal : (DI or Microphone Input) 12 Hz – 700,000 Hz, +/- 1 dB < 0.
Contact Info: Fredenstein Professional Audio by Orion Communication 7F-1, No. 582, Ruei Guang Rd. Neihu District Taipei 114 Taiwan Phone : Email : Web : + 886-2-2657-2618 info@fredenstein.com www.fredenstein.
