MICpre60

The MICpre60 is meant for recording studios where the highest sound quality is demanded. It is ideal for recording engineers that prefer the sound of an analog mic preamplifier over digital ones.

The inputs are Balanced Mic and Line. Output is Balanced too. The microphone gain pot is replaced by a selection of gain settings. Simply use a jumper to select a gain to match the microphone in use. This is not as convenient as using a rotary pot but the benefit is superior performance. The gain ranges from 38dB to 63dB in five settings.

Gain Selector
2.0mV Noise at 60dB Gain

The photo above left is the selector for the gain. Position 1 is the highest gain (63dB). Postion 5 is the lowest at 38dB. When in use, select the gain to match your source be it a microphone or a keyboard.

One of the main concerns with a 63dB amplification is noise. The photo on the right is with the Gain set at 63dB. As can be seen, the noise level is only +/- 2mV. This is superimposed over my oscilloscope floor noise which is at +/- 0.8mV. All inputs are shorted to ground for this measurement.


Micpre60 Schematic

The schematic above is the full MICpre60. The mic input is configured as Sziklai pairs, commonly known as Complementary Feedback Pairs. It has similarities with Darlingtons in that both exhibit high impedance.

Between the two Sziklai pairs are the pcb headers in place of a potentiometer. Only one gain setting can be selected with a jumper. The output is Balanced with a 10dB gain at maximum. This is equivalent to the three red leds lighting up above the 0dB in the mixer. In use, the output should be adjusted for unity gain for optimal performance.

To power the MICpre60, check out our PSU15REG. It is equipped with voltage regulators for +15V and -15V.

Specfications

MIC Gain Settings
1=63dB
2=53dB
3=49dB
4=43dB
5=38dB

Electronically Balanced Mic and Line Inputs
Electronically Balanced Output

Mic Input Impedance = 1.2K ohms
Line Input Impedance = 10K ohms

PCB = 7.1" X 2.2" (180mm x 56mm)
Double Sided | FR4

MICpre60
Kit
US$ 75.50

MICpre60
Pcb
US$ 34.50

$40 Minimum Order on Check Out
Shipping info



60 Downes Street | Calais | ME 04619 | USA