|The Mic Pre with oversized
input transformer, brand Haufe, Germany, and fully balanced input amplifier with
hand picked semiconductors, which is optimzed in every respect, is based on more
than 30 years experience in the design of large format audio mixing consoles.
The sound performance is a unique combination of transparency and warmth; the
TM101 remains pristine and natural with all microphones and all signals. Outstanding
noise performance at low and high gain settings and the massive headroom of +
30 dBu, also at low gain settings, very flat phase response down to 20 Hz and
a power bandwidth of 100 kHz are some of the technical qualities of this mic
The maximum Gain is 70 dB; ribbon
microphones with very low output level can be used without problems. The lowest
gain setting is 25 dB; high level condenser microphones can be used without pad.
The mic input can be used with line level signals if the 25 dB input pad is switched
on. The headroom with pad is + 30 dBu. The attenuation circuit is entirely switched
out to avoid additional load on the input when the pad is off. Another switch
activates the 48 volts phantom power supply.
The Noise Performance of the TM101
Mic Pre is very close to a 'wire with amplification'. At maximum gain of 70 dB,
the noise figure is better than 1.6 dB. This means, that the total noise at the
amplifier output is 1.6 dB higher than the noise of the source resistance of
a typical microphone, which is 200 ohms. Much more important is the noise performance
at lower gain settings that are commonly used. The TM101 is optimized for this
range; the typical noise figure is 1.3 dB at 50 dB gain and remains below 2 dB
down to 40 dB gain.
The Input CMRR is better than
70 dB up to a frequency of 15 kHz; typical values are: 15 kHz - 75 dB, 1 kHz
- 94 dB, 40 Hz - 103 dB. The input impedance is higher than 2 kOhms in the frequency
range from 20 Hz to 20 kHz. Well-balanced, soft RF filters maintain a power bandwidth
of more than 100 kHz and an extremely flat phase response but provide effective
protection against RF interference and the intermodulation effects caused by
parasitic auto oscillation. The Frequency Response is
flat from 30 Hz to 20 kHz. The low frequency phase response, which is crucial
for the sound performance at the low end of the audio band remains below 10° down
to 30 Hz, even though a soft subsonic filter protects the amplifier against impact
noise and infrasonic interferences.
The additional, electronically balanced Line-Input is
totally separated from the microphone input and has its own input amplifier and
its own gain pot with +/- 20 dB range. The input impedance is higher than 10
kOhms; the headroom is more than + 30 dBu. This input is selected by the LINE
The Phase Reversal Switch operates on both inputs.
The High-Pass Low-Pass Filter is
inserted by the FILT switch. The sweep ranges are from less than 20 Hz to 600
Hz for the high-pass filter and from more than 20 kHz down to 2 kHz for the low
pass filter. The steepness of the high-pass filter is 24 dB/oct, the low-pass
filter has a steepness of 12 dB/oct. Both are active, maximum flat RC filters.
The Level Indicator displays the
actual output level on a multicolor LED using different colors. With green color
the level is above - 20 dB. The color changes to yellow at 0 dB and turns to
orange and red when the level raises. The remaining headroom with red color is
more than 5 dB.
The electronically balanced output can handle levels of more than + 30 dBu. The source resistance is lower than 50 ohms in the frequency band 20 Hz to 20 kHz. THD remains below 0.1 % up to output levels of more than + 28 dBu.
The TM101 mic pre is a 2U ToolMod modules. It fits in all ToolMod frames. Horizontal and vertical versions are available.