Audio Engineering

782 Chapter 27

1000

μF/25V

NON-POLAR

10 K

Reverselog taper

2

7

(^68)
5
4
3
1K
100 K
IC-1
  
V
22pF0.1/
25V
100
10K
V
0.1/
25V
200pF
FB-2
10
Optional outputtransformer circuit
Output Out
10 K
470
μF/25V
Non-polar
220
μF/25 V
220
μF/25 V
TOV
^15 or
18V
15V or18V
0V
TOV
10 K
  
1N40011N4001 1N40011N4001
Mountclose toop amp
JE-110K-HPC
150/10 K
20 dB PAD
619
619
(^2) Input 3 1
169
Case
1
5
4
8 6 7
Schematic diagram of typical microphone preamplifier utilizing JE-110K-HPCNotes:
IC-1

integrated circuit opamp such as MA-332 or NE-5534.
Gain range:
24dB
Keep traces short between transformer and opamp.All resistors

1%, metal film.
200pF cap in feedback

2 μ
sec compensation.
FB-2

ferrite bead available from Jensen.
Capacitors marked*
 polystyrene or polypropylene.
58dB.
1.2.3.
5.6.7.
4.
Figure 27.14 : Microphone transformer.