CTH Parts Lists


Amplifier - Input Stage, Buffers, and Rail Splitter

Part Quantity Description
Circuit Board
- 1 Compact Tube Hybrid - Complete Circuit Board
Potentiometers
Volume 1 Dual 50k Audio Taper - Alps RK097
Resistors
R1L, R1R, R5L, R5R 6 1/8W 1% Metal Film Resistor 1MΩ
R2L, R2R 2 1/8W 1% Metal Film Resistor 300Ω
R3L, R3R 2 1/8W 1% Metal Film Resistor 1.5kΩ
R4L, R4R 2 1/8W 1% Metal Film Resistor 10Ω
R6L, R6R 2 1/8W 1% Metal Film Resistor 30.9kΩ
R7L, R7R 2 1/8W 1% Metal Film Resistor 18kΩ
R8L, R8R 2 1/8W 1% Metal Film Resistor 2kΩ
R9L, R9R, R10L, R10R, R2S, R3S 6 1/8W 1% Metal Film Resistor 22Ω
R11L, R11R, R12L, R12R 4 1/8W 1% Metal Film Resistor 220Ω
R13L, R13R 2 1/2W 1% Metal Film Resistor 1k5Ω
R14L, R14R, R15L, R15R 2 1/8W 1% Metal Film Resistor 100kΩ
R16L, R16R, R17L, R17R,
R5S, R6S, R7S, R8S
8 1/8W 1% Metal Film Resistor 6.8Ω
R18L, R18R 2 1/8W 1% Metal Film Resistor 0-150Ω - See Notes
R1S, R4S 2 1/8W 1% Metal Film Resistor 2.7kΩ
R9S 1 1/8W 1% Metal Film Resistor 100Ω
Capacitors
C1L C1R 2 Aluminum Electrolytic 10u 10V
C3L, C3R, C7L 2 Metalized Polyester/Polypropylene Film Capacitor 100n 63V
C2L, C2R, C5L, C5R, C6L, C6R 6 Non-polar Aluminum Electrolytic 10u 25V
C4L, C4R 2 Metalized Polyester/Polypropylene Film Capacitor 220n 100V
C1S 2 Mica Capacitor 10p 300V
Diodes
D1L, D1R 2 2mA Current Regulating Diode
D2L, D2R 2 4.3mA Current Regulating Diode
Transistors
Q4L, Q4R, Q1S 3 BC560C - See Notes
Q5L, Q6L, Q6L, Q6R, Q7L, Q7R, Q2S 7 BC550C - See Notes
Q8L, Q8R, Q3S, Q5S 4 BC337/25 - See Notes
Q9L, Q9R, Q4S, Q6S 4 BC327/25 - See Notes
Integrated Circuits
ICL, ICR, IC1S 3 High Beta, Jfet Input Single Opamp - TL081
IC1 1 High Beta, Jfet Input Dual Opamp - TL082
IC2S 1 Rail Splitter - TLE2426
Vacuum Tubes
V1L 1 Dual Triode 12AU7 or 6922 - Or similar tubes
Miscellaneous
Tube Socket 1 9 Pin PCB Mount Tube Socket
Opamp Sockets 4 8 Pin Dip Socket


Resistors

  • 1/8W Resistors are 1% Metal Film type - 7mm lead spacing.
  • 1/2W Resistors are Vishay CCF55 or same size.
  • R18L and R18R are for reducing gain when low Z headphones are used. The prototype users have felt that 56Ω is a good compromise value.

Capacitors

  • C1L, C1R are Aluminum Electrolytic - 2mm lead spacing 5mm diameter.
  • C2L, C7L, C7R are Polyester/Polypropylene Film - 5mm lead spacing 2.5mm width.
  • C3L, C2R, C5L, C5R, C6L, C6R are Non-Polar Aluminum Electrolytic -2mm lead spacing 5mm diameter.
  • C4L, C5L are Polyester/Polypropylene Film - 5mm lead spacing 5mm width.
  • C1S is a Mica Capacitor - Approximately 2.5mm lead spacing 2mm width.

Diodes

  • D1L, D1R are 2mA Current Regulating Diodes 1N5305
  • D2L, D2R are 4.3mA Current Regulating Diodes 1N5313

Transistors

  • Q4L, Q4R, Q1S are BC560C. These MUST be the "C" HFE class devices.
  • Q5L, Q5R, Q6L, Q6R, Q7L, Q7R, Q2S are BC550C. These MUST be the "C" class devices.
  • Q8L, Q8R, Q3S, Q5S are BC337. These MUST be the "25" HFE class devices.
  • Q9L, Q9R, Q4S, Q6S are BC327. These MUST be the "25" HFE class devices..
  • Warning: Don't, Do not substitute transistors unless you know what you're doing. Do not substitute other classes of the BC devices. Use the "C" class and the "25" class.

Integrated Circuits

  • ICL, ICR, IC1S are TL081 single opamp, but any high β, jfet input opamp with the same pinout can be substituted.
  • IC1 is TL082 dual opamp, but any dual high β, jfet input opamp with the same pinout can be substituted.
  • IC2S is the TLE2426 rail splitter. I am not aware of any substitutes.
  • WARNING: Do not use BJT input opamps as they will not satisfactorily zero the offset.

Tubes

  • The design center is the 12AU7 tube. But, because of the flexible front end design, many other tube types are possible. 

 

Epsilon 12 Muting Circuit with Indicator Lights

Part Quantity Description
Resistors
R1E, R2E, R6E 3 1/8W 1% Metal Film Resistor 33kΩ
R3E 1 1/8W 1% Metal Film Resistor 100kΩ
R4E 1 1/8W 1% Metal Film Resistor 2kΩ
R5E 1 1/8W 1% Metal Film Resistor 470kΩ
R8E 1 1/8W 1% Metal Film Resistor 62kΩ
R7E, R9E 2 1/8W 1% Metal Film Resistor 2kΩ
R10E 1 1/2W 1% Metal Film Resistor 1kΩ
Transistors
Q1E, Q2E 2 BC550C
Q3E 1 MPSA14 Darlington
Q41E, Q5E 2 BC560C
Capacitors
C1E 1 Metalized Polyester/Polypropylene Film Capacitor 1u 63V
C2E, C3E 1 Non Polar Aluminum Electrolytic 100u 16V
C4E 2 Metalized Polyester/Polypropylene Film Capacitor 100n 63V
Diodes
D1E, D2E, D3E 3 Small Signal Diode - 1N4148
LE1, LE2 2 2.1V LED
Integrated Circuits
ICE 1 TL081 Opamp
Relay
K1E 1 Miniature 12V Relay - NEC 551-EC2-12NJ


Resistors

  • 1/8W Resistors are 1% Metal Film type - 7mm lead spacing.
  • 1/2W Resistors are Vishay CCF55 or same size.

Capacitors

  • C1E is Polyester/Polypropylene Film - 5mm lead spacing 5mm width.
  • C2E, C3E are Non Polar Aluminum Electrolytic - 3.5mm lead spacing 8mm diameter.
  • C4E, C5E are Polyester/Polypropylene Film - 5mm lead spacing 2.5mm width.

Diodes

  • All 1N4148 or equivalent.
  • LEDs are 2.1V 3mm Green and Red or a 3mm Dual LED to go under the tube.

Transistors

Integrated Circuits

  • ICE is TL081 single opamp, but any high β, jfet input opamp with the same pinout can be substituted.
  • WARNING: Do not use BJT input opamps as they may not work properly.

Relay

  • The relay is NEC EC2 or exact equivalent in specs, size, and pin spacings.

 

Full Excel BoM

This Excel spreadsheet has the parts lists and part numbers for the 2011 version of the Compact Tube Hybrid PCB. Most of the parts have Mouser part numbers. A few key components come from Digikey.

CTH 2015d Excel BoM