sahib
Well-known member
MICPRE THREE
MICPRE THREE is a cut down version of MICPRE ONE http://groupdiy.com/index.php?topic=52443.0
It shares the same fully balanced topology as the MICPRE ONE but without the instrument input, monitoring and metering.
MICPRE THREE is similar in topology to the transformerless design Graham used on the Amek M2500 mixing console and the original Angela console of 1982.
A number of improvements have been made, but the design retains the use of parallel matched transistors and constant current sources. Exceptional noise performance has been achieved. Particularly at low gain settings. The signal path is balanced throughout.
0dB to 66dB of gain is selected in 6dB steps by a rotary switch and this is followed by the fader stage which provides an additional 4dB of gain and up to 24dB of control to adjust between switch settings and also to attenuate the final output to suit consumer interface.
Switches are fitted for input impedance selection, a passive high pass filter before the preamplifier, phase and phantom power.
Typical specification, both paths:
Mic. input impedance: switchable 5k ohms/600 ohms
High pass filter: 120Hz @ 6dB/octave (nominal).
Frequency response: +/- 0.5dB, 20Hz-80kHz (up to 60dB gain).
Phase response (EQ out): +/-30 deg., 20Hz-80kHz (up to 60dBgain).
Maximum output (into 100k ohms): +27dBu
THD&N (+10dBu input signal): better than 0.05%, 20Hz-20kHz (up to 60dBgain).
Mic. EIN, 22Hz-22kHz, RMS, 150 ohm source: -128dBu.
Output impedance: 75 ohms
Can be purchased through White Market ;
http://groupdiy.com/index.php?topic=52462.msg668904#msg668904
MICPRE THREE is a cut down version of MICPRE ONE http://groupdiy.com/index.php?topic=52443.0
It shares the same fully balanced topology as the MICPRE ONE but without the instrument input, monitoring and metering.
MICPRE THREE is similar in topology to the transformerless design Graham used on the Amek M2500 mixing console and the original Angela console of 1982.
A number of improvements have been made, but the design retains the use of parallel matched transistors and constant current sources. Exceptional noise performance has been achieved. Particularly at low gain settings. The signal path is balanced throughout.
0dB to 66dB of gain is selected in 6dB steps by a rotary switch and this is followed by the fader stage which provides an additional 4dB of gain and up to 24dB of control to adjust between switch settings and also to attenuate the final output to suit consumer interface.
Switches are fitted for input impedance selection, a passive high pass filter before the preamplifier, phase and phantom power.
Typical specification, both paths:
Mic. input impedance: switchable 5k ohms/600 ohms
High pass filter: 120Hz @ 6dB/octave (nominal).
Frequency response: +/- 0.5dB, 20Hz-80kHz (up to 60dB gain).
Phase response (EQ out): +/-30 deg., 20Hz-80kHz (up to 60dBgain).
Maximum output (into 100k ohms): +27dBu
THD&N (+10dBu input signal): better than 0.05%, 20Hz-20kHz (up to 60dBgain).
Mic. EIN, 22Hz-22kHz, RMS, 150 ohm source: -128dBu.
Output impedance: 75 ohms
Can be purchased through White Market ;
http://groupdiy.com/index.php?topic=52462.msg668904#msg668904
