HP Aikido Stereo 9-Pin B manual Configuring the PCB as a Line Amplifier

Page 8

GlassWare Audio Design

7

Configuring the PCB as a Line Amplifier

The Aikido topology makes a perfect line amplifier, as it offers low distortion, low output impedance, and excellent power-supply noise rejection— all without a global feedback loop. The key points are not to use capacitor C3. For guidance on part values, look at the page 12, which lists several line-amplifier design examples. Calculating R15’s value is easy; it equals R16 against [(mu -2)/(mu + 2)]. For example, a triode with a mu of 20 results in R15 = 100k x (20 – 2)/(20 + 2) = 81.8k (82k)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B+

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

C5

C6

 

 

 

 

 

 

 

 

R9

 

 

 

 

 

 

R7

C1

 

out

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4

R8

 

J8 (J9)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

out

R15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

in

R3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R1

C11

 

 

C12

R12

R13

R14

R16

 

 

 

 

R2

R5

 

 

 

 

 

 

R11 C3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(input) V2, V3

(output) V1, V4

 

 

 

 

Typical Part Values () Parentheses denote recommended values

 

 

 

 

 

 

 

 

 

 

 

 

6CG7 & 6DJ8

 

 

6CG7 & 6CG7

12AU7 & 12AU7

12AU7 & 12BH7

 

B+ Voltage =

170V - 250V (200V)

 

 

200V - 300V (300V)

200V - 300V (250V)

200V - 300V (300V)

 

Heater Voltage =

6.3V

 

 

6.3V

12.6V

 

12.6V

 

R1,5,6,7,12,13,14

=

 

1M

 

 

1M

1M

 

1M

 

 

 

R2,4

=

 

270 - 1k (470)*

 

 

470 - 2k (870)*

470 - 2k (680)*

470 - 2k (1k)*

 

 

 

R3,9,10

=

 

100 - 1k (300)*

 

 

Same

Same

 

Same

 

 

 

R8,11

=

 

200 - 330 (200 10mA)*

270 - 680 (270)*

180 - 470 (200)*

200 - 470 (523)*

 

 

R15

=

 

87.5k

 

 

83.2k

80k

 

79.3k

 

 

 

R16

=

 

100k

 

 

Same

Same

 

Same

 

 

 

 

 

 

 

 

 

*High-quality resistors essential in this position

 

 

 

 

 

 

 

 

 

 

 

 

All resistors 1/2W or higher

 

 

 

 

 

 

 

 

C1

=

 

0.1 - 4µF* Film

 

 

Same

Same

 

Same

 

 

 

 

 

C2

=

 

0.1 - 4µF* Oil

"

 

 

 

 

"

 

"

 

 

 

 

 

C3

=

 

none

"

 

 

 

 

"

 

"

 

 

 

 

 

C5

=

 

1 - 10µF* Film or Oil

"

 

 

 

 

"

 

"

 

 

 

 

 

C6

=

 

0.1 - 1µF* Film or Oil

"

 

 

 

 

"

 

"

 

 

C7,8,9,10

=

 

47µF - 1kµF, 16V

"

 

 

 

 

"

 

"

 

 

 

C11,12

=

 

0.1µF 160V(optional)

 

 

Same

None

 

None

 

 

 

 

 

 

 

 

 

*Voltage rating must equal or exceed B+ voltage

 

 

 

 

 

(input) V2, V3 =

6CG7, 6FQ7

 

 

6CG7, 6FQ7

12AU7, 5814, 5963,

12AU7, 5814, 5963,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6189, ECC82

6189, ECC82

 

 

(output) V1, V4=

6DJ8, 6922,

 

 

6CG7, 6FQ7

12AU7, 5814, ECC82

12BH7, ECC99

 

 

 

 

 

 

 

 

 

7308, E88CC

 

 

 

 

 

 

 

 

 

 

 

Image 8
Contents User Guide PCB Features Rev. C OverviewAikido Amplifier Introduction to the AikidoC1 & C2 Filament Jumper Wire Schedule Heater IssuesPower Supply Cathode Resistor Values Tube SelectionInternal Shields Configuring the PCB as a Line Amplifier 6CG7 & 6DJ8 6CG7 & 6CG7 12AU7 & 12AU7 12AU7 & 12BH7Configuring the PCB as a Headphone Amplifier Switch FrontAssembly Let me know what you thinkPin Aikido Schematic Rev. C Top Side PCB Mechanical Layout ECC81