The Cavalli-Kan Kumisa III Stereo Headphone Amplifier

The Cavalli-Kan Kumisa III Stereo Headphone Amplifier

Parts list for standard configuration

The table below illustrates a standard configuration CK²III amplifier. It includes parts for both stereo channels, the power supply and the enclosure. See the sections below for specific parts recommendations and options. Items shown in italic are available from the AMB audio shop.

Part	Quantity	Description
Circuit board
-	1	CK²III printed circuit board
Potentiometers
Volume	1	Alps RK27112A 50KΩ dual log taper, panel-mount
R19, R43	2	3/8" multi-turn cermet trimpot 1KΩ
Resistors
R16, R21	2	1/8W 1% metal film resistor 1MΩ
R1, R25	2	1/8W 1% metal film resistor 475Ω
R7, R10, R31, R34	4	1/8W 1% metal film resistor 11KΩ
R8, R9, R32, R33, R20, R22, R44, R46	8	1/8W 1% metal film resistor 3.32KΩ
R12, R13, R17, R36, R37, R41	6	1/8W 1% metal film resistor 1.82KΩ
R2, R3-R5, R6, R26, R27-R29, R30	10	1/8W 1% metal film resistor 825Ω
R18, R42	2	1/8W 1% metal film resistor 2.37KΩ
R11, R14, R35, R38	4	1/8W 1% metal film resistor 182Ω
R40, R49, R51	3	1/8W 1% metal film resistor 10KΩ
R15, R39	2	1/8W 1% metal film resistor 301KΩ
R23, R24, R47, R48	4	1W 5% metal oxide resistor 0.47Ω
Capacitors
C33-C36	4	aluminum electrolytic capacitor 2200µF 35V
C3, C4, C12, C13	4	aluminum electrolytic capacitor 1000µF 16V
C37, C38	2	aluminum electrolytic capacitor 220µF 50V
C19, C22, C23, C24	4	bipolar aluminum electrolytic capacitor 10µF 50V
C39, C40	2	metallized polyester capacitor 2.2µF 63V
C7, C16	2	metallized polyester capacitor 0.47µF 63V
C20, C21	2	metallized polyester capacitor 0.1µF 63V
C1, C2, C10, C11	4	metallized polypropylene capacitor 0.047µF 100V
C5, C6, C14, C15	4	multilayer ceramic capacitor 10pF 100V NP0/C0G
C8, C9, C17, C18	4	multilayer ceramic capacitor 220pF 100V NP0/C0G
C25-C32	8	multilayer ceramic capacitor 0.1µF 100V X7R
Integrated Circuits
U1	1	TI/Burr-Brown OPA2134PA dual operational amplifier
VR1	1	Positive voltage regulator 7815
VR2	1	Negative voltage regulator 7915
Transistors
Q2, Q15	2	N-channel low noise JFET 2SK170BL
Q3, Q16	2	P-channel low noise JFET 2SJ74BL
Q4, Q5, Q8, Q9, Q10, Q17, Q18, Q21, Q22, Q23	10	NPN low noise BJT BC550C
Q1, Q6, Q7, Q11, Q14, Q19, Q20, Q24	8	PNP low noise BJT BC560C
Q13, Q26	2	NPN medium power BJT BD139-16 or MJE243
Q12, Q25	2	PNP medium power BJT BD140-16 or MJE253
Diodes
D1-D8	8	1A rectifier 1N4004
LED	1	Your choice
Power transformer
-	1	Amveco TE62033 15V+15V toroidal with wire leads
Miscellaneous
-	2	TO-220 PCB-mount heatsink Aavid-Thermalloy 592502B03400G
-	4	TO-220 heatsink Aavid-Thermalloy 577202B00000G (see notes below)
-	2	TO-220 heatsink mounting kit (if required, see notes below)
-	1	heatsink thermal compound (if required, see notes below)
-	1	DIP-8 socket
-	2	RCA phono jack, panel mount
-	1	1/4" stereo headphone jack, panel mount, isolated
-	4	0.100" 2-circuit pin header, plug and crimp terminals (for audio inputs and transformer secondary connection)
-	1	IEC power entry module with fuse drawer
-	1	5x20mm 250mA slow blow fuse
-	1	SPST power switch (optional)
-	1	knob for Volume
-	-	hookup wire
-	-	heat-shrink tubing
-	1	Hammond 1455Q220x or 1455Q160x (see below)
-	-	imperial #4-40 or metric M3 machine screws, hex nuts
-	-	other hardware as needed

Parts recommendations & options

To obtain the blank CK²III circuit board and some related parts, visit the AMB audio shop. You can get almost everything else from the vendors listed on the AMB Audio DIY Page. The favorite vendors are Mouser and Digi-Key.

The following is a list of recommendations and options. Please read through this carefully before you order any parts.

Resistors

All except R23, R24, R47, R48: 1/8W or 1/4W 1% metal film type
Lead spacing 0.300"
- Vishay-Dale CMF series RN55D (Mouser)
- Yageo MFR-25 or MFR-25S series (Digi-Key)
- Panasonic EROS2P series (Digi-Key)
- Xicon MF series (Mouser)
- Koa Speer MF series (Mouser)
R23, R24, R47, R48: 1W 5% miniature non-inductive metal oxide type
Lead spacing 0.500"
- Xicon MO series (Mouser 281-0.47-RC)
- Panasonic ERG1S series (Digi-Key P0.47W-1BK-ND)

Notes about R12, R13, R36, R37:

At the default value of 1.82KΩ, the voltage gain of this amplifier is 9x (19dB). If these resistors are changed to 825Ω the gain will drop to 4.1x (12.3dB). If you choose to use 825Ω resistors, the value of C5, C6, C14 and C15 should be increased to 22pF to ensure stability.

Notes about R40:

R40 is the current limit resistor for the LED. The optimum value of this resistors depends on your choice of LED. Use this online LED resistor value calculator to determine what value your R40 should be. Since the LED circuit is across the rails, the supply voltage used for this calculator should be 30V. Depending on the value of the resistor and the voltage drop across it, you should be mindful to use a resistor rated at high enough power. The actual power dissipation is computed by:

Watts = V² / R
where V is the voltage dropped and R is the value of R40. For example, if you use a 10KΩ resistor and the voltage dropped is 28V, then the power dissipation will be about 0.08W. In this case a 1/8W or 1/4W resistor will work fine.

The type of resistor is not critical as long as it fits well.

Trimpots

R19, R43, 3/8" multi-turn cermet
1KΩ
Lead spacing 0.100" inline

Vishay-Sfernice T93YA (Mouser 72-T93YA-1K)
Vishay-Spectrol 64W (Mouser 594-64W102)
Vishay-BC CT94W (Digi-key CT94EW102-ND)
Bourns 3296W (Mouser 652-3296W-1-102, Digi-Key 3296W-102LF-ND)

Panel-mount potentiometers

Volume: 50KΩ or 10KΩ dual log taper

Alps RK27112A (AMB audio shop)
Noble AP25 (Michael Percy Audio)
TKD 2P2511

Capacitors

C5, C6, C14, C15: multilayer ceramic capacitor (NP0 or C0G)
10pF
Lead spacing 0.100" or 0.200"
- Kemet Golden-max C315 series
  (Mouser 80-C315C100J1G, Digi-Key 399-4140-ND)
- Vishay Mono-Kap series (Digi-Key BC1001CT-ND)
C8, C9, C17, C18: multilayer ceramic capacitor (NP0 or C0G)
220pF
Lead spacing 0.100" or 0.200"
- Kemet Golden-max C315 series
  (Mouser 80-C315C221J1G, Digi-Key 399-4163-ND)
- Vishay Mono-Kap series (Digi-Key BC1017CT-ND)
C25-C32: multilayer ceramic capacitor (X7R)
0.1µF 100V
Lead spacing 0.200"
- Kemet C322 (Mouser 80-C322C104K1R, Digi-key 399-4328-ND)
C39, C40: metallized polyester capacitor
2.2µF 63V
Lead spacing 0.200"
- AVX BF/BQ series (Mouser 581-BQ054D0225K)
C7, C16: metallized polyester capacitor
0.47µF 63V
Lead spacing 0.200", 0.300" 0.400"
- Vishay-Roederstein MKT1817 (Mouser 75-MKT1817447064)
- Vishay-Roederstein MKT1818 (Mouser 75-MKT1818447064)
C20, C21: metallized polyester or multilayer ceramic capacitor
0.1µF 63V
Lead spacing 0.100", 0.200"
- AVX BF/BQ (Mouser 581-BQ014D0104J, Digi-Key 478-3368-ND)
- Wima MKS2 (Mouser 505-MKS2-.1/63/5)
- Kemet C320 (Mouser 80-C320C104K5R, Digi-key 399-4264-ND)
C1, C2, C10, C11: metallized polypropylene capacitor
0.047µF 63V
Lead spacing 0.200"
- Wima MKP2 (Mouser 505-MKP20.047/100/5)
- Vishay-BC MKP416 (Digi-Key BC2068-ND)
C33-C36: aluminum electrolytic capacitor 35V low-ESR high-reliability
2200µF
Lead spacing: 0.300", diameter: 16mm or 18mm
- Nichicon HE (Mouser 647-UHE1V222MHD)
- Nichicon PW (Mouser 647-UPW1V222MHD6)
- Panasonic FC (Digi-Key P10335-ND)
C3, C4, C12, C13: aluminum electrolytic capacitor 16V low-ESR high-reliability
1000µF
Lead spacing: 0.200", diameter: 10mm
- Nichicon HE (Mouser 647-UHE1C102MPD)
- Nichicon PW (Mouser 647-UPW1C102MPD)
- Panasonic FC (Digi-Key P10253-ND)
- Panasonic FM (Digi-Key P12366-ND)
C37, C38: aluminum electrolytic capacitor 50V low-ESR high-reliability
220µF
Lead spacing: 0.200", diameter: 10mm
- Nichicon HE (Mouser 647-UHE1H221MPD)
- Nichicon PW (Mouser 647-UPW1H221MPD)
- Panasonic FC (Digi-Key P10325-ND)
- Panasonic FM (Digi-Key P12397-ND)
C19, C22, C23, C24: aluminum bipolar electrolytic capacitor 50V capacitor
10µF
Lead spacing: 0.100", diameter: 7mm
- Nichicon VP (Mouser 647-UVP1H100MED)
- Panasonic SU (Digi-Key P1280-ND)

Notes about C8, C9, C17, C18:

These capacitors are for stabilizing the CFP output stage. While in many cases these capacitors may be omitted without ill effects (and would also speed up the amplifier's slew rate slightly), it is recommended that you install these to ensure stability, particularly if you do not have the necessary test equipment to observe the square wave behavior of the amplifier at RF high frequencies.

Notes about C19, C22, C23, C24:

Instead of the listed 10µF bipolar electrolytic capacitors, you may use 1µF 63V polyester film capacitors with 0.200" lead spacing instead. You will also have to increase R49, R51 to 100KΩ and R15, R39 to 3.01MΩ with this option.

Diodes

D1-D8: rectifier diode
Lead spacing 0.200" or 0.300"
- 1N4004 (DO-41) 1A rectifier diode (Mouser 821-1N4004, Digi-Key 1N4004-ND)
- MUR820 (TO-220) 8A 200V ultrafast recovery rectifier (Mouser 863-MUR820G, Digi-Key MUR820GOS-ND)
LED:
Lead spacing 0.100"
Your choice of size and color (affects value of R40, see above).

Transistors

Q2, Q15: N-channel low-noise JFET 2SK170BL (TO-92)
(AMB audio shop, B&D Enterprises, MCM Electronics)
Q3, Q16: P-channel low-noise JFET 2SJ74BL (TO-92)
(AMB audio shop, B&D Enterprises, MCM Electronics)
Q4, Q5, Q8, Q9, Q10, Q17, Q18, Q21, Q22, Q23: NPN small signal BJT BC550C (TO-92)
(AMB audio shop, Mouser)
Q1, Q6, Q7, Q11, Q14, Q19, Q20, Q24: PNP small signal BJT BC560C (TO-92)
(AMB audio shop, Mouser)
Q13, Q26: NPN medium power transistor
- BD139-16 (TO-126 or TO-225AA)
  (Mouser 512-BD13916STU, Digi-Key BD13916STU-ND)
- MJE243 (TO-225AA)
  (Mouser 863-MJE243G, Digi-Key MJE243GOS-ND)
Q12, Q25: PNP medium power transistor
- BD140-16 (TO-126 or TO-225AA)
  (Mouser 512-BD14016STU, Digi-Key BD14016STU-ND)
- MJE253 (TO-225AA)
  (Mouser 863-MJE253G, Digi-Key MJE253GOS-ND)

Integrated circuits

U1: Dual low-noise precision opamp with JFET inputs (DIP-8)
- TI/Burr-Brown OPA2134PA (Mouser 595-OPA2134PA, Digi-Key OPA2134PA-ND)
- TI/Burr-Brown OPA2132PA (Mouser 595-OPA2132PA, Digi-Key OPA2132PA-ND)
VR1: 3-terminal +15V fixed voltage regulator (TO-220)
- 7815 (Mouser 512-MC7815CT, Digi-Key MC7815ACTOS-ND)
- LM340T-15 (Digi-Key LM340T-15-ND)
VR2: 3-terminal -15V fixed voltage regulator (TO-220)
- 7915 (Mouser 512-MC7915CT, Digi-Key MC7915CTFS-ND)
- LM320T-15 (Digi-Key LM320T-15-ND)

Heatsinks

The voltage regulators should be cooled with onboard heatsinks. The circuit board is designed to accept the following heatsinks:

Aavid-Thermalloy 592502B03400G (Mouser 532-592502B34, Digi-key HS372-ND)
Wakefield 242-125AB-22
Fischer Electronik FK218 32 (conrad.de, other European vendors)

The output transistors should also be cooled by heatsink(s) to avoid thermal runaway and to make quiescent adjustments easier. You could either add individual (per-device) heatsinks, or bolt them all onto a common heatsink or to an enclosure wall.

For individual heatsinks, the following (or something similar) is recommended:

Aavid-Thermalloy 577202B00000G (Mouser 532-577202B00, Digi-key HS107-ND)

TO-220 heatsink mounting kit

If the tops of the voltage regulator or output transistor heatsinks will be in close proximity to the enclosure's top metal cover, sidewall or any other object (when the board is installed), then you should mount the regulators/transistors to the heatsinks using TO-220 mounting kits, which electrically isolate their mounting tabs from the heatsinks. Otherwise, you may mount them to the heatsinks directly.

Radio Shack 276-1373 (Mica)
Aavid-Thermalloy 4880G (Thermalfilm), 4880SG (Thermalsil) or 4880MG (Mica) (Mouser 532-4880, 532-4880SG or 532-4880M; Digi-Key HS417-ND)
Bergquist Sil-Pad K4-54 (Digi-key BER219-ND)

Heatsink thermal compound

Not needed if using mounting kits with Thermalsil or Sil-Pad isolators.

Radio Shack 276-1372
Wakefield 120-SA (Mouser 567-120-SA; Digi-Key 345-1006-ND)
others

IC sockets for opamps

DIP-8 with gold contacts

Mill-max 115-93-308-41-003 (Mouser 575-113308; Digi-Key ED5308-ND)
Aries 08-3518-10 (Digi-Key A400-ND)

Connectors

RCA phono input jacks, panel-mount: your choice
- Switchcraft (various styles)
- Vampire (various styles)
- Cardas (various styles)
- WBT (various styles)
- others
1/4" stereo headphone jack, panel-mount: your choice
The headphone jack must be isolated from the chassis
- Switchcraft N112B (Mouser 502-N112B; Digi-Key SC1123-ND)
- Neutrik NJ3FP6C (Mouser 568-NJ3FP6C)
- Neutrik NCJ6FI-S (Mouser 568-NCJ6FI-S)
- Neutrik NMJ6HC-S (Mouser 550-NMJ6HCS)
- Re'An NYS212 (Mouser 568-NYS212)
- Pomona 6877 (Mouser 565-6877)
- others
PCB audio input block, transformer secondary block: (optional, allows easy wiring connect/disconnect to PCB):
- Molex KK 22-23-2021 0.100" header, 2-circuit (Mouser 538-22-23-2021; Digi-Key WM4200-ND)
  mating plug 22-01-3027 (Mouser 538-22-01-3027; Digi-Key WM2000-ND),
  crimp terminals 08-50-0114 (Mouser 538-08-50-0114; Digi-Key WM1114-ND)
IEC power entry module with fuse drawer (optionally with power switch)
Your choice, make sure there is enough room in the case.
- Corcom
- Qualtek
- Schurter
- others

Power transformer

Amveco 15V+15V dual-secondary 7VA toroidal transformer TE62033
(Digi-Key TE62033-ND)
other similar

Chassis / case

The circuit board is designed to slide into a Hammond 1455Q series compact extruded aluminum enclosure. The board can also be mounted using standoffs into other suitable enclosures.

Hammond 1455Q2201 (metal end panels) or 1455Q2202 (plastic end panels)
Use this if the power transformer is to be mounted in the same enclosure as the CK²III board.
(Mouser 546-1455Q2201, 546-1455Q2201-BK, 546-1455Q2202 or 546-1455Q2202BK)
Hammond 1455Q1601 (metal end panels) or 1455Q1602 (plastic end panels)
Use this if the power transformer is to be located in a separate box.
(Mouser 546-1455Q1601, 546-1455Q1601BK, 546-1455Q1602 or 546-1455Q1602BK)
others

Miscellaneous

Knob for volume control (must fit the potentiometer shaft diameter and style, your choice)
SPST toggle or rotary switch for power on/off (optional, if IEC power entry module does not have one built-in).

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