M-1
Microphone Preamplifier:
The
M-1 Mic Preamp is among the finest mic preamps in the world. It
provides the accuracy and transparency that is missing in other mic
preamps. No matter what your application, the M-1 will provide superior
sound quality. The world's best input transformer (Jensen JT-16-B),
best op-amp (990 discrete op-amp) and the elimination of all capacitors
from the signal path combine to provide the highest performance.
The M-1 has a
19" wide mainframe rack-mount chassis (1.75"H x 19"W x 8"D) and can be
ordered with 1 to 4 channels. There are two meter options and the best
Jensen output transformer (JT-11-BMQ) is also available as an option.
Additional channels and options can be easily added later up to the
total capacity of the mainframe.
The M-1 was
introduced in 1987 and while sonically identical to the M-2 there are a few control differences.
The
M-1 has a two-section gain-pot providing continuously variable
adjustment in two overlapping ranges that are selected by the "HIGH
GAIN" switch. (The M-2 has a 16 position
gain-switch with 1% metal-film resistors providing accurate and
repeatable gain settings. Since the "HIGH GAIN" switch isn't necessary,
the M-2 is available with either a "20 OHM MIC" switch OR a "20dB PAD" switch).
Highlights:
•
JT-16-B Input Transformer. Jensen's best mic input model.
•
990
Discrete Op-Amp. Faster, quieter, more powerful and better sounding
than typical monolithic op-amps.
•
Elimination Of All Coupling Capacitors From The Signal Path. Results in
less degradation of the audio signal.
Standard
Features:
•
Dual Range Gain Control And 'High Gain' Switch. Provides great feel and
resolution for easy and accurate adjustments.
•
Polarity Reverse Switch.
•
Phantom Power Switch.
•
All
Front Panel Switches Are LED Illuminated.
•
Gold Plated XLR Connectors for maximum reliability.
•
Ground Lift Switch On Each Channel. Helpful for eliminating ground
loops.
•
Toroidal Power Transformer With Additional Shielding. Eliminates hum
problems so no external power supply is needed.
•
Universal Power Supply. Internal switch provides six primary voltage
choices to accommodate use anywhere in the world.
•
Chassis Ground Isolation Switch. Helpful for eliminating ground loops.
•
Built To Order, the way YOU want It. Various options can be easily
field installed at a later date.
Options:
•
VU-1 meter. Very accurate and informative 20 segment LED meter card
with separate peak LED for monitoring preamp output.
•
PK-1 Peak LED metering only (not required if VU-1 is installed).
•
JT-11-BMQ Output Transformer. Jensen's best line output transformer.
•
Pin
2 Or Pin 3 High. Can be ordered either way and internal jumpers make
changes in the field easy.
 |
| M-1 Channel Detail |
| |
 |
| M-1 Back Panel Detail |
Condensed
Specifications:
| E.I.N., 20Hz - 20kHz
Unweighted |
150 Ohm source |
-129 |
dBu |
|
0 Ohm source |
-132 |
dBu |
| Maximum Input Level |
>30Hz |
+12 |
dBu |
| Maximum Output Level At
990 Output |
75 Ohm load |
+24 |
dBu |
| CMRR |
100Hz |
100 |
dB |
|
10kHz |
80 |
dB |
| Deviation From Linear
Phase |
20Hz - 120kHz |
<2 |
deg |
| THD, JT-16-B, (Below
Saturation) |
20Hz |
0.036 |
% |
|
30Hz |
0.022 |
% |
|
50Hz |
0.010 |
% |
|
1kHz |
0.003 |
% |
| THD, JT-16-B & 990: |
|
|
|
| 60db Gain, 10k Ohm Load,
+24dBu Output |
10kHz |
0.005 |
% |
|
1kHz |
0.004 |
% |
| 40db Gain, 600 Ohm Load,
+24dBu Output |
10kHz |
0.003 |
% |
|
1kHz |
0.003 |
% |
| 40db Gain, 75 Ohm Load,
+24dBu Output |
10kHz |
0.030 |
% |
|
1kHz |
0.005 |
% |
| DC Offset |
|
<100 |
uV |
|