MICpreLIVE
The
MICpreLIVE is meant for LIVE events like Bands. The
design is slightly simpler in that the mic amplification
is by two transistors instead of four that is used
in the MICpre60. The Mic maximum gain is 440x. So
a 1mVrms output from a microphone can be amplified
to 0.44Vrms. That works out to 53dB.
But
it doesn't stop there. The Balanced Output stage has
a gain of 3.5x, effectively raising the total gain
to 1.56Vrms (64dB) if need be.
Fig 1 - 1.4mV Noise at 0dBu (0.775Vrms) Output |
Fig 2 - 3.4mV Noise at +6dBu (1.56Vrms) Output |
Noise
level is low enough for LIVE applications. At 0dBu
(0.775Vrms), the noise at the balanced output is only
1.4mVpk (Fig 1). At +6dBu (1.56Vrms), the noise recorded
is 3.4mVpk (Fig 2). When using a mixer, it is customary
not to exceed 0dBu.
MicpreLIVE Schematic |
The
schematic above is the full MICpreLIVE. The input
signal is amplified by two low noise transistors used
in the microphone stage. The output of the op amp
is bootstrap to the transistor, thus resulting in
a higher impedance.
In
this MICpreLIVE, a potentiometer is used for gain
adjustment. This is a more practical approach than
using jumpers as in the MICpre60.
To
power the MICpreLIVE, check out our PSU15REG.
It is equipped with voltage regulators for +15V and
-15V.
PCB
= 5.2" X 2.2" (133mm x 57mm)
Double Sided | FR4
|
