AES Cohen August 15 2006

Western Electric 1930s-1940s

Western Electric 1920s

German Broadcasting 1940s

RCA BA-1A from 1945

1940s - 1950s

Langevin 1947

Siemens & Halske 1952

Siemens & Halske 1952Modified by G J Cohen 1996

Radiotron Designer’s handbook 4th ed. P789

AWA Consolette.

Courtesy Phil Punch, Electric Avenue Studios

Radiotron Designer’s handbook 4th ed. P792-793

Altec M11 system 1950

Morgan Jones 1995

AKG C24 microphone

Treharne 1958

Langevin AM16 1961John Hall is credited with this design, and he subsequently left Langevin and went toAltec where his name can be found on the similar PP 9470A/9475A amps of 1964.

Langevin AM16 1964

Bailey. Wireless World

Graeme J Cohen. Sept 1984

Graeme J Cohen.

Hybrid Input Concept

Graeme J Cohen. Sept 1984 Double Balanced Microphone amplifier

AES preprint 2106

1 2 3 4 5 6 7 8

A

B

C

D

87654321

D

C

B

A

Title

Number RevisionSize

A3

Date: 7-Aug-2008 Sheet of File: D:\CLIENTS\COHEN\DUALMI~1\PCB\AMP22.SCHDrawn By:

R16K8 1/2W

D136V 1W

R21K

R533K

VR1

10K

D2

1N4004

+48

OM1556 Dual Mic Amp 2006

I. DuRIEU

2.2

240V AC

1 1

I

A

O

U5LM317T

C1

1000uF 35V

C2

1000uF 35V

D31N4004

D41N4004

T116V AC 1A plug pack

C7

330uF 63V

C8330uF 63VD5

1N4004

D61N4004

Nom +70V

I

G

O

U1

LM7918

I

G

O

U2

LM7818

D7 1N4004

D8 1N4004

+18

-18

+18

-18

H3RED 3mm

T2BC548

T3BC548R3

1K

R639K

R8220K

R103K9

R121K6

C92u2 50V BP

C11100uF

Nom +25VH1Blue

C13

10uF

C14

10uF

C15

0.1uF

1

2

3

6

7

8

910

11

12

+in

-in

+G

E

-GRI

VEE

VCC+out

-out

U3OM1556

12345 6 7 8

9101112

CSW1SW-12WAY

12

3

SW3A

87

9SW3C

Nom -25V

C12100uF

D9BAT85

BR1W04

+18

+18

D10BAT85R14 open

R15 750RR16 270RR17 130RR18 68R R19 11R0

R20 12R

R23 1R0

R24 36R R25 20R

R276K8 0.01%

R29 1K5 0.01%

R301K5 0.01%C16

220uF 50V

C17220uF 50V

C181uF MKT

C191uF MKT

cable toinput XLRs Cable to

output XLRs

R286K8 0.01%

**

**

**

** **

Matched

R31

10R + 2 beads

R32

10R + 2 beads

Power

Power LED also providesmin load for LM317

R33

12KH2Yellow

45mA max

C20

0.1uF

R263K3

R34

270R

R35

270R

12

3SW2A

+48

Phantom

LNK1

P48 Enable

12

3

SW4A

87

9SW4C

Phase Reverse

50/600 Ohms O/P Z

BR2W04

+18

-18

C21

0.1uF

LpkLED

LpkLED

Left PEAK LED

+18

-18

H4RED 3mm

T4BC548

T5BC548R4

1K

R739K

R9220K

R113K9

R131K6

C102u2 50V BP

RpkLED

Right PEAK LED

Gain

Bolt1Bolt2Bolt4C27

0.1uF

Bolt3

220uF 50V Farnell 876-7424Panasonic ECA Series

All 3 regs on vertical 24 C/W sinks

X8 X9

Sub boardAll buttons are drawn in the released position

45

6

SW2B

Multiple switch sections are in parallel

45

6

SW3B

11

1210

SW3D

45

6

SW4B

11

1210

SW4D

12

3

SW9A

87

9SW9C

12

3SW8A

12

3

SW10A

87

9SW10C

12

3

SW11A

45

6

SW8B4

5

6

SW9B

11

1210

SW9D

45

6

SW10B

11

1210

SW10D

45

6

SW11B

C3

1000uF 25V

C221uF MKT

C4

1000uF 25V

C5

1000uF 25V

C231uF MKT

C6

1000uF 25V

R36100K

R37100K


X10X12

12

3

SW5A

Ground Lift

45

6

SW5B

LNK2

LNK3

LNK4

**

**

LNK5123

X2

3PIN123

X3

3PIN

Sold

er p

ads 30dB

25dB20dB15dB10dB6dB

35dB40dB45dB

50dB55dB

60dB

R38 12R

R39 3R3R41 1R8

R43 22R

(6R0)

(0R958)

1

2

3

6

7

8

910

11

12

+in

-in

+G

E

-GRI

VEE

VCC+out

-out

U4OM1556

12345

6 7

89101112

CSW6SW-12WAY

D11BAT85

BR3W04

+18

D12BAT85R44 open

R45 750RR46 270RR49 130RR50 68R R51 11R0

R52 12R

R60 1R0

R61 36R R62 20R

R636K8 0.01%

R65 1K5 0.01%

R661K5 0.01%C32

220uF 50V

C33220uF 50V

C341uF MKT

C351uF MKT

cable toinput XLRs Cable to

output XLRs

R646K8 0.01%

**

**

**

** **

Matched

R67

10R + 2 beads

R68

10R + 2 beads

R69

12KH5Yellow

R703K3

+18

+48

Phantom

C38100pF

C39100pF

LNK6

P48 Enable

BR4W04

+18

-18

RpkLED

Gain


X4 X6

Sub board

All buttons are drawn in the released position

Multiple switch sections are in parallel

C28

1000uF 25V

C411uF MKT

C29

1000uF 25V

C30

1000uF 25V

C421uF MKT

C31

1000uF 25V

R71100K

R72100K


X5X7

Ground Lift

LNK7

LNK8

LNK9

**

**

LNK10123

X11

3PIN123

X13

3PIN

Sold

er p

ads **

**

30dB25dB20dB15dB10dB6dB

35dB40dB45dB

50dB55dB

60dB

R53 12R

R55 3R3R58 1R8

R73 22R

(6R0)

(0R958)

D131N4004

D141N4004

Phase Reverse

50/600 Ohms O/P Z

****

R47

270R

R48

270R

****

Solder pads

123

X1

3PINScreened power cable

** **

** **

C24100pF

C25100pF

C26100pF

**

**NPO

NPO

NPO

NPO

NPO

NPO

C40100pF

(330mW)

OM1556 designed in 1984

1997 - 2006

Graeme J Cohen. Sept 1996

Split Cascode Amplifier

AES preprint 4296

Dual OM1556 2006OM1556 designed in 1984

AES Cohen August 15 2006

Documents

Transcript of AES Cohen August 15 2006