13
LT1115
1115fa
Figure 5. High Performance Transformer Coupled Microphone Pre-Amp
Risetime of High Performance
Transformer Coupled Microphone
Pre-Amp (Figure 5)
Frequency Response
(Gain = 20dB) Balanced In/
Balanced Out (Figure 5)
THD + Noise vs Frequency
(Gain = 20dB) Balanced In/
Balanced Out (Figure 5)
FREQUENCY (Hz)
0.0005
TOTAL HARMONIC DISTORTION + NOISE (%)
0.010
0.001
0.1
1
20 100 1k 20k
V
S
= ±18V
V
IN
= 0.95V
RMS
R
L
= 600Ω
R
S
= 150Ω
T
A
= 25
°
C
LT1115 • TA15
FREQUENCY (Hz)
AMPLITUDE (dB) REFERRED TO 1kHz
– 1.000
– 2.000
– 3.000
– 4.000
– 5.000
1.0000
0.0
10
1k
10k
100k
100
V
S
= ±18V
V
IN
= 0.95V
RMS
R
L
= 600Ω
R
S
= 150Ω
T
A
= 25
°
C
LT1115 • TA16
RISETIME OF PRE-AMP
A
V
= 20dB
V
IN
= 400mV
2kHz SQUARE WAVE MEASURED AT SINGLE-
ENDED OUTPUT BEFORE TRANSFORMER
–
+
–
+
LT1115
LT1010CT
LT1097
INPUT
CASE
JENSEN
JE-16-A/B
JENSEN
JE-11-BM
WHT
BLK
BRN
BRN
ORANGE
150Ω
MICROPHONE
RED
RED
YELLOW
YEL
6.19k
100Ω
100k
100k
100Ω
100pF
22Ω
49.9Ω
~250Ω
SELECT
FOR 2mA
2N4304**
2mA
3
2
7
6
4
1µF
35V
1µF
35V
1µF
35V
1µF
35V
1µF
35V
470µF
35V
470µF
35V
1µF
35V
18V
18V
–18V
–18V
1µF
1µF
1N4002
1N4002
V
–
V
+
IN
2.5k
REV. AUDIO
TAPER
BOOST
2.49k
OUT
10Ω
10Ω
10k
OPTIONAL
SINGLE-ENDED TO
BALANCED OUTPUT
TRANSFORMER
4.99Ω
3
2
7
6
4
RESISTORS 1% METAL FILM
CAPACITORS—BYPASS: LOW ESR
OTHER: HIGH QUALITY FILM
NOTE: USE SINGLE POINT GROUND
*
**
JENSEN NETWORK VALUES—FACTORY SELECTED.
JE-16-A/B & JE-11-BM AVAILABLE FROM:
JENSEN TRANSFORMERS
10735 BURBANK BLVD.
N. HOLLYWOOD, CA 91601
(213) 876-0059
OR USE 2mA CURRENT SOURCE
LT1115 • TA13
+
+
+
+
+
+ +
+
TYPICAL APPLICATIO S
U
