Volume 1ma

V2

Hoffman Amplifiers Plexi 6V6

D

www.hoffmanamps.com

V1

1

23

45 6

78

9 12

3

45

6

78

9

L12

A

T S

G

1m

.00

22

+

22u

f

82

0

2.7

k

.68

.02

21

00

k

10

0k

82

0.68

10

0k

33k

1m

47

0

1m

10k

47

k

10

0k

82

k

10k/3w

1 o

hm

1 o

hm

47k

+10

/10

0v

+10

/10

0v

22

0k/3

w

Choke

50kl

B AC

PT

Re

ds

1n5

40

8

1n5

40

8

Bias Range

10

0k

10

0k

.02

2

.02

2

V4 V5

4 5

67

81

23

OT4 5

67

81

23

OT

+ +

16/4

75

v

10k/3w 20k/3wE

68k

68k

.02

2

.02

25

00

p

47

0k

Normal Bright

50

0p

47

0k

Volume 1ma

.02

2

1

23

45 6

78

9

V3

Treble 250kl Middle 25kl Presence 5klBass 1ma

RG174

Shielded

.1/250v

Fe

ed

ba

ck

100k

1.5

k

1.5

k

470/3w

470/3w

Chassis

Ground

Lug

Master 1ma

.1/2

50

v

1n4007

15k

Ground

Buss

3.125" x 6.75"

V1-A

C10

.022

R24

10k

R24

1m

R23

1m

R17

1ma

R22

470

NEUTRAL

LINE

GROUND

2 AMP

SLO BLO

6.3

VA

C

7

8

5

3

4

V2-BV3

V4

6

81

2

3

V2-A

3

2

1R2

68k

R1

1m

V4V3V2V1

4 4 2

799

5 5

R4

100k

C3

.022uf

R12

100k

C7

500p

R13

820

C8

.022uf

R14

100k

R15

33k

C11

.1/250v

R18

25kl

12AX7

12AX7

6V6

6V6

7

6

C1

22uf

R5

820

A B C

AB

C

D

E

LED

T1

T2

SW1

J1

Tre

ble

Ba

ss

Mid

R16

250kl

C9

.022uf

Pre

se

nce C12

.1/250v

1

2

3

6

7

8

R25

5kl

C13

.022

C14

.022

12AX7

R20

82k

R21

100k

V1-BR3

68k

R6

100k

C4

.0022uf12AX7

C2

.68uf

R7

2.7k

E

R27

100k

R28

100k

R29

1.5k

R30

1.5k

R31

470/3 watt

R32

470/3 watt

V5

9

5

V5

1N4007

R36

50kl

R35

15k

R38

220k/3wattD

Choke

C17

40uf

C18

20uf

C19

20uf

C20

20uf

R39

20k/3wR40

10k/3w

4 2

7

C15-C16

10uf/100v

R37

47k

T3

Feedback

R26

47k

Feedback

R33

1 ohm

R34

C6

.68uf

1N5408

1N5408

E

C21

16uf

R41

10k/3w

4

8

16SW2

+ +

_ _

+

+ + + + +

J3

J2

Speakers

Primary

Jack

R42

180

EL34 World Tube amp Library page Hoffman Amplifiers parts catalog

Hoffman Layout diagram hookup information

www.hoffmanamps.com

Hoffman Plexi 6V6

8

8

5

3

4

Bias

Pot

R19

1ma

Ma

ste

r

R8

1ma

VO

LU

ME

R10

470k

R11

470k

R9

1ma

VO

LU

ME

C5

500p

Normal

Bright

Yellows and

White not used

Blue

Brown

402 400 276 238 223

.77

127

1.56

161

.84

134

238

135

21 21

33

185 170

399

399

26mv

26mv

-35

307

vac

Voltages are noted in red text

Voltages are DC volts unless noted

394

394

Hoffman Amplifiers Plexi 6V6 www.hoffmanamps.com

D

50kl

B ACE

Clickable Links

EL34 World Tube amp Library page

Hoffman Amplifiers parts catalog

Hoffman Layout diagram hookup information www.hoffmanamps.com

Hoffman Plexi 6V6

T

SG

T

SG

FUSE

IEC receptacle

Green

Black

To heaters

To heaters

18 watt

Power

Transformer

2 Amp slo-blo

On/Off

Switch

AD BC

+ +

20

uf/5

00

v

+ +

20

uf/5

00

v

+ +

20

uf/5

00

v

+ +

40

uf/5

00

v

Board Connections

300 vac

Chassis Ground Lug

Rotary

Switch

18 watt

Output

Transformer

Pin 3

Pin 3

Board A

16

8

4

Common

+

-

Black White

Black Red 240v

Black White 120v

Primary jack

N L

YXUO

40x20x20x20/500v Cap can

Transformer center taps

grounded here

Feedback

6.3

va

c

LED1

80

Board Diodes

Board Diodes

Bias Tap