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

0.010

0.001

0.1

1

20

100

1k

20k

LT1115 • TA15

FREQUENCY (Hz)

– 1.000

– 2.000

– 3.000

– 4.000

– 5.000

1.0000

0.0

10

1k

10k

100k

100

LT1115 • TA16

RISETIME OF PRE-AMP

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

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