12AX7 Phono Tube Preamplifier User Manual (1)

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12AX712AX712AX712AX7 PhonoPhonoPhonoPhono

TubeTubeTubeTube Pre-AmplifierPre-AmplifierPre-AmplifierPre-Amplifier

UserUserUserUser ManualManualManualManual

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[[[[12AX712AX712AX712AX7 PhonoPhonoPhonoPhono TubeTubeTubeTube Pre-AmplifierPre-AmplifierPre-AmplifierPre-Amplifier ]]]] AnalogAnalogAnalogAnalogMetricMetricMetricMetric

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INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

The circuit design is referenced to VTL phono tube preamplifier. It support both MM orMC phono input with RIAA compensation. It uses four 12AX7 vacuum tube in serialcommon-cathode configurations and buffer stage to provide sufficient voltage gain forweak phono input signal. The input impedance can be changed by the DIP switch. Thesignal paths of this PCB layout is designed in symmetry for both channels. Dedicatedpower rails, ground, and signal paths, althogether are taken into considerations so thatall are to minimize the parasitics, cross interference, and influence of RFI.




FEATURESFEATURESFEATURESFEATURES

• Four 12AX7 vacuum tubes.

• Support both MM and MC.

• RIAA compensation.

• Input impedance can be varied by DIP switch or modified resistances by advancedusers.

• Two single-ended inputs and two single-ended outputs.

• Symmetric layout design and signal paths with minimum parasitic.

• Dedicated ground and power rails layout design.

• Four large reservoir decoupling capacitors for power rails.

• Power requirements: one 260V(100mA) DC and one 12.6V(2A) DC.

• PCB dimension: 20.2mm (W) x 13.6mm (L)

• PCB thickness: 2.4mm, double layer, 2oz copper.

PRECAUTIONSPRECAUTIONSPRECAUTIONSPRECAUTIONS

• Do not use any body parts to touch the metal parts of the kit after power up or poweroff, since the high voltage capacitors may not fully discharge. It may cause seriouselectric shock.

• Use a power transformer with fuse (1-3A) socket to limit the supply current in case ofshort circuit or incorrect assembly.

• Double check the assembled components with the schematics.

• Do not attempt the measure the voltage by multimeter with hand after power up. Theprobes of the multimeter should be mounted by some stands to the points of themeasurement before switching on the power supply.

• Turn off the power supply if you observe any smokes or hear strange sound comingout from the transformer or board. If there is short circuit, the transformer will begetting very hot shortly.




PROCEDURESPROCEDURESPROCEDURESPROCEDURES

1. Hook up all the components according to the schematic, part list, and photos.Notice to the polarity of the high voltage electrolytic capacitors (C2, C2B, C3,C3B, C10, C10B, C13, C13B, C14, C14B). There are no polarities of the thin filmcapacitors.

2. MM mode: Pin 5 set off of SW1 and SW2.

3. MC mode: Pin 5 set on of SW1 and SW2.

4. Change input impedance: Pin 1, 2, 3, 4 and 6 of SW1 and SW2.

5. Apply either one or two 260V DC to J3 and 12.6V DC to J4. Connect the GND ofthese two connector. If you only have one 260V DC, connect the two '260V DC'pins together.

6. If everything work fine, the tubes will be led up gradually. Then, apply signals toconnectors J1 and obtain corresponding output signal at J2.

7. Enjoy it.




CHECKLISTCHECKLISTCHECKLISTCHECKLIST

1. The polarity of the high voltage capacitorsC2, C2B, C3, C3B, C10, C10B, C13, C13B,C14, C14B.

2. The supply voltages at connectors (J3 and J4). Check the two DC pins of J3 whetherconnected to power supply.

3. Short the GND of J1, J2, J3 and J4 together.

If you have any problem in assembly, please contact us by email [email protected]

mailto:[email protected]


1

1

2

2

3

3

4

4

5

5

6

6

D D

C C

B B

A A

Title

Number RevisionSize

C

Date: 6/4/2010 Sheet ofFile: G:\AnalogMetric\..\phono vtl.SchDoc Drawn By:

123

J3

B+GND

123

J1

MC IN

123

J5

Out

GND

GND

12

J4

HT

H1H2

Analog Metric

12AX7 Phono Pre-Amplifier ref VTL

41

2

3 5

V1A12AX7

6

7

8

V1B12AX7

41

2

3 5

V2A12AX7

6

7

8

V2B12AX7

41

2

3 5

V3A12AX7

6

7

8

V3B12AX7

41

2

3 5

V4A12AX7

6

7

8

V4B12AX7

47uF/50V

C20.1uF

C1 GND

2.7KR1

2.7K

R2

1.35

KR

3

510

R4

250

R5

47K

R7

GND123

J2

MM IN GND

R_MC

L_MC

R_MM

L_MM

H1

H2

1uFC3

1MR8

150pFC4

100pF

C5

0.01uF

C6

33pF

C7

240KR11

H1

H2

0.22uF

C8

2.7KR14

2uF

C9

1MR17

100K

R61W

274K

R101W

4.7K

R91W

2.7K

R121W

274K

R131W

980

R151W

980

R161W

120uF/400V

C13

47uF/400V

C14

GND GND

47K

R22

1W1K

R23

1W

B1+B2+

B1+

ROUT

LOUT

5600pF

C11

680K

R19

1K

R21

47K

R201600pF

C12

510R18

GND

220uF/50V

C10

47uF/50V

C2B0.1uF

C1B GND

2.7KR1B

2.7K

R2B

1.35

KR

3B

510

R4B

250

R5B

47K

R7B

GND

H1

H2

1uFC3B

1MR8B

150pFC4B

100pF

C5B

0.01uF

C6B

33pF

C7B

240KR11B

H1

H2

0.22uF

C8B

2.7KR14B

2uF

C9B

1MR17B

100K

R6B1W

274K

R10B1W

4.7K

R9B1W

2.7K

R12B1W

274K

R13B1W

980

R15B1W

980

R16B1W

120uF/400V

C13B

47uF/400V

C14B

GND GND

47K

R22B

1W1K

R23B

1W

B2+

5600pF

C11B

680K

R19B

1K

R21B

47K

R20B1600pF

C12B

510R18B

GND

220uF/50V

C10B

R_MM

R_MC

L_MC

L_MM

ROUT

LOUT

1 2 3 4 5 678910

ON DIP

1112

1 2 3 4 5 6

SW1

1 2 3 4 5 678910

ON DIP

1112

1 2 3 4 5 6

SW2

P0C101 P0C102

P0C1B01 P0C1B02

P0C201 P0C202

P0C2B01 P0C2B02

P0C301 P0C302

P0C3B01 P0C3B02

P0C401 P0C402

P0C4B01 P0C4B02

P0C501 P0C502

P0C5B01 P0C5B02

P0C601 P0C602

P0C6B01 P0C6B02

P0C701 P0C702

P0C7B01 P0C7B02

P0C801 P0C802

P0C8B01 P0C8B02

P0C901 P0C902

P0C9B01 P0C9B02

P0C1001 P0C1002

P0C10B01 P0C10B02

P0C1101 P0C1102

P0C11B01 P0C11B02

P0C1201 P0C1202

P0C12B01 P0C12B02

P0C1301

P0C1302

P0C13B01

P0C13B02

P0C1401

P0C1402

P0C14B01

P0C14B02

P0J101

P0J102

P0J103

P0J201

P0J202

P0J203

P0J301

P0J302

P0J303

P0J401

P0J402

P0J501

P0J502

P0J503

P0R101

P0R102

P0R1B01

P0R1B02

P0R201

P0R202

P0R2B01

P0R2B02

P0R301

P0R302

P0R3B01

P0R3B02

P0R401

P0R402

P0R4B01

P0R4B02

P0R501

P0R502

P0R5B01

P0R5B02

P0R601

P0R602

P0R6B01

P0R6B02

P0R701

P0R702

P0R7B01

P0R7B02

P0R801

P0R802

P0R8B01

P0R8B02

P0R901

P0R902

P0R9B01

P0R9B02

P0R1001

P0R1002

P0R10B01

P0R10B02

P0R1101

P0R1102

P0R11B01

P0R11B02

P0R1201

P0R1202

P0R12B01

P0R12B02

P0R1301

P0R1302

P0R13B01

P0R13B02

P0R1401

P0R1402

P0R14B01

P0R14B02

P0R1501

P0R1502

P0R15B01

P0R15B02

P0R1601

P0R1602

P0R16B01

P0R16B02

P0R1701

P0R1702

P0R17B01

P0R17B02

P0R1801

P0R1802

P0R18B01

P0R18B02

P0R1901 P0R1902

P0R19B01 P0R19B02

P0R2001 P0R2002

P0R20B01 P0R20B02

P0R2101 P0R2102

P0R21B01 P0R21B02

P0R2201 P0R2202

P0R22B01 P0R22B02

P0R2301 P0R2302

P0R23B01 P0R23B02

P0SW101

P0SW102

P0SW103

P0SW104

P0SW105

P0SW106

P0SW107

P0SW108

P0SW109

P0SW1010

P0SW1011

P0SW1012

P0SW201

P0SW202

P0SW203

P0SW204

P0SW205

P0SW206

P0SW207

P0SW208

P0SW209

P0SW2010

P0SW2011

P0SW2012

P0V1A01

P0V1A02

P0V1A03

P0V1A04

P0V1A05

P0V1B06

P0V1B07

P0V1B08

P0V2A01

P0V2A02

P0V2A03

P0V2A04

P0V2A05

P0V2B06

P0V2B07

P0V2B08

P0V3A01

P0V3A02

P0V3A03

P0V3A04

P0V3A05

P0V3B06

P0V3B07

P0V3B08

P0V4A01

P0V4A02

P0V4A03

P0V4A04

P0V4A05

P0V4B06

P0V4B07

P0V4B08

P0J303

P0R2301

P0V2B06

N0B1+

P0J302

P0R23B01

P0V4B06

N0B2+

P0C4B01

P0C401

P0C13B02

P0C1302

P0C14B02

P0C1402

P0J102

P0J202

P0J301

P0J502

P0R1B01

P0R101

P0R8B01

P0R801

P0R9B01

P0R901

P0R11B01

P0R1101

P0R12B01

P0R1201

P0R16B01

P0R1601

P0R17B01

P0R1701

P0R18B02

P0R1802

P0SW101

P0SW102

P0SW103

P0SW104

P0SW106

P0SW201

P0SW202

P0SW203

P0SW204

P0SW206

P0V1A02

P0V3A02

P0J402

P0V1A04

P0V2A04

P0V3A04

P0V4A04

N0H1

N0H1

N0H1

N0H1

N0H1

P0J401

P0V1A05

P0V2A05

P0V3A05

P0V4A05

N0H2

N0H2

N0H2 N0H2

N0H2

P0C9B02

P0C12B01

P0J503

P0R17B02

P0R20B01

N0LOUT

N0LOUT

P0C1B01

P0C2B01

P0J203 N0L0MC

N0L0MC

P0C4B02

P0C5B02

P0J201

P0R7B02

P0R8B02

P0SW205

P0V3B07

N0L0MM

N0L0MM

P0C1B02

P0C2B02

P0R1B02

P0R2B02

P0R3B02

P0R4B02

P0R5B02

P0V3A03

P0C102

P0C202

P0R102

P0R202

P0R302

P0R402

P0R502

P0V1A03

P0C3B01

P0SW208

P0C3B02

P0R6B01

P0V3A01

P0C301

P0SW108

P0C302

P0R601

P0V1A01

P0C5B01

P0C7B02

P0C10B01

P0R9B02

P0V3B08

P0C501

P0C702

P0C1001

P0R902

P0V1B08

P0C6B01 P0R10B01

P0V3B06 P0C6B02

P0R11B02

P0V4A02

P0C601 P0R1001

P0V1B06 P0C602

P0R1102

P0V2A02

P0C7B01

P0C8B01

P0R13B01

P0V4A01

P0C701

P0C801

P0R1301

P0V2A01

P0C8B02

P0R14B02

P0V4B07

P0C802

P0R1402

P0V2B07

P0C9B01

P0R15B02

P0V4B08

P0C901

P0R1502

P0V2B08

P0C10B02

P0C11B02

P0R18B01 P0R19B02

P0C1002

P0C1102

P0R1801 P0R1902

P0C11B01

P0R19B01 P0R20B02

P0R21B02

P0C1101

P0R1901 P0R2002

P0R2102

P0C12B02 P0R21B01

P0C1202 P0R2101

P0C13B01

P0R6B02

P0R22B02

P0C1301

P0R602

P0R2202

P0C14B01

P0R10B02

P0R13B02

P0R22B01 P0R23B02

P0C1401

P0R1002

P0R1302

P0R2201 P0R2302

P0R2B01

P0SW2012

P0R201

P0SW1012

P0R3B01

P0SW2011

P0R301

P0SW1011

P0R4B01

P0SW2010

P0R401

P0SW1010

P0R5B01

P0SW209

P0R501

P0SW109

P0R7B01

P0SW207

P0R701

P0SW107

P0R12B02

P0V4A03

P0R1202

P0V2A03

P0R14B01

P0R15B01

P0R16B02

P0R1401

P0R1501

P0R1602

P0C902

P0C1201

P0J501

P0R1702

P0R2001

N0ROUT

N0ROUT

P0C101

P0C201

P0J103 N0R0MC

N0R0MC

P0C402

P0C502

P0J101

P0R702

P0R802

P0SW105

P0V1B07

N0R0MM

N0R0MM

N0B1+ P0J303

P0R2301

P0V2B06

N0B2+ P0J302

P0R23B01

P0V4B06

P0C4B01

P0C401

P0C13B02

P0C1302

P0C14B02

P0C1402

P0J102

P0J202

P0J301

P0J502

P0R1B01

P0R101

P0R8B01

P0R801

P0R9B01

P0R901

P0R11B01

P0R1101

P0R12B01

P0R1201

P0R16B01

P0R1601

P0R17B01

P0R1701

P0R18B02

P0R1802

P0SW101

P0SW102

P0SW103

P0SW104

P0SW106

P0SW201

P0SW202

P0SW203

P0SW204

P0SW206

P0V1A02

P0V3A02

N0H1

P0J402

P0V1A04

P0V2A04

P0V3A04

P0V4A04

N0H2

P0J401

P0V1A05

P0V2A05

P0V3A05

P0V4A05

N0LOUT P0C9B02

P0C12B01

P0J503

P0R17B02

P0R20B01

N0L0MC

P0C1B01

P0C2B01

P0J203

N0L0MM

P0C4B02

P0C5B02

P0J201

P0R7B02

P0R8B02

P0SW205

P0V3B07

P0C1B02

P0C2B02

P0R1B02

P0R2B02

P0R3B02

P0R4B02

P0R5B02

P0V3A03

P0C102

P0C202

P0R102

P0R202

P0R302

P0R402

P0R502

P0V1A03

P0C3B01

P0SW208

P0C3B02

P0R6B01

P0V3A01

P0C301

P0SW108

P0C302

P0R601

P0V1A01

P0C5B01

P0C7B02

P0C10B01

P0R9B02

P0V3B08

P0C501

P0C702

P0C1001

P0R902

P0V1B08

P0C6B01 P0R10B01

P0V3B06 P0C6B02

P0R11B02

P0V4A02

P0C601 P0R1001

P0V1B06 P0C602

P0R1102

P0V2A02

P0C7B01

P0C8B01

P0R13B01

P0V4A01

P0C701

P0C801

P0R1301

P0V2A01

P0C8B02

P0R14B02

P0V4B07

P0C802

P0R1402

P0V2B07

P0C9B01

P0R15B02

P0V4B08

P0C901

P0R1502

P0V2B08

P0C10B02

P0C11B02

P0R18B01 P0R19B02

P0C1002

P0C1102

P0R1801 P0R1902

P0C11B01

P0R19B01 P0R20B02

P0R21B02

P0C1101

P0R1901 P0R2002

P0R2102

P0C12B02 P0R21B01

P0C1202 P0R2101

P0C13B01

P0R6B02

P0R22B02

P0C1301

P0R602

P0R2202

P0C14B01

P0R10B02

P0R13B02

P0R22B01 P0R23B02

P0C1401

P0R1002

P0R1302

P0R2201 P0R2302

P0R2B01

P0SW2012

P0R201

P0SW1012

P0R3B01

P0SW2011

P0R301

P0SW1011

P0R4B01

P0SW2010

P0R401

P0SW1010

P0R5B01

P0SW209

P0R501

P0SW109

P0R7B01

P0SW207

P0R701

P0SW107

P0R12B02

P0V4A03

P0R1202

P0V2A03

P0R14B01

P0R15B01

P0R16B02

P0R1401

P0R1501

P0R1602

N0ROUT P0C902

P0C1201

P0J501

P0R1702

P0R2001

N0R0MC

P0C101

P0C201

P0J103

N0R0MM

P0C402

P0C502

P0J101

P0R702

P0R802

P0SW105

P0V1B07

AnalogAnalogAnalogAnalog MetricMetricMetricMetric12AX7 Phono PreAmplifier (Stereo) ref VTLComponentsComponentsComponentsComponents ValuesValuesValuesValues QuantityQuantityQuantityQuantity RemarkRemarkRemarkRemarkC1, C1B 0.1uF/100V 2 Metalized Film CapC2, C2B 47uF/50V 2 Electrolytic CapC3, C3B 1uF/400V 2 MKP Film CapC4, C4B 150pF/250V 2 Metalized Film CapC5, C5B 100pF/250V 2 Metalized Film CapC6, C6B 10nF/250V 2 Metalized Film CapC7, C7B 33pF/250V 2 Metalized Film CapC8, C8B 0.22uF/250V 2 MKP Film CapC9, C9B 2uF/250V 2 MKP Film CapC10, C10B 220uF/50V 2 Electrolytic CapC11, C11B 5.6nF/50V 2 Metalized Film CapC12, C12B 1.6nF/50V 2 Metalized Film CapC13, C13B 120uF/400V 2 Electrolytic CapC14, C14B 47uF/400V 2 Electrolytic CapR1, R1B, R2, R2B 2.7K 1/4W 4R3, R3B 1.35K 1/4W 2R4, R4B, R18, R18B 510R 1/4W 4R5, R5B 250R 1/4W 2R6, R6B 100K 1W 2R7, R7B, R20, R20B 47K 1/4W 4R8, R8B 1M 1/4W 2R9, R9B 4.7K 1W 2R10, R10B, R13, R13B 274K 1W 2R11, R11B 240K 1/4W 2R12, R12B 2.7K 1W 2R15, R15B, R16, R16B, R23, R23B1K 1W 6R14, R14B, R17, R17B 1M 1/4W 4R19, R19B 680K 1/4W 2R21, R21B 1K 1/4W 2R22, R22B 47K 1W 2V1,V2, V3, V4 12AX7 4Mini 9 Pin PCB Mount Tube Socket 4SW1, SW2 DIP12 22-Pin Connector 13-Pin Connector 43mm screw &copper rod 4PCB 1

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12AX7 Phono Tube Preamplifier User Manual (1)