• on Audio/Video/Photography
  • Published in issue 1/2017 on page 74
About the article

Cool Power with D-Watt

A high-performance amplifier with lots of output power

Cool Power with D-Watt
Elektor has a long history and a good reputation with high-end yet DIY, audio projects. This time we proudly present a new power amplifier aimed at all audio enthusiasts, built around a digital audio driver IC and operating in class-D. This has the advantage that the amplifier can deliver a lot of output power (like 200 watts into 8 ohms) with very low heat dissipation. Say goodbye to big heatsinks!
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Component List
Default: 5%, 0.25W
R1,R8 = 1kOhm
R2,R23,R24,R30,R34,R36,R37,R46,R50,R54 = 10kOhm
R3,R20 = not mounted
R4 = 2kOhm 1%
R5 = 330Ohm
R6,R18 = 3kOhm 1%
R7,R52 = 120kOhm
R9 = 470Ohm
R10,R11,R15,R31 = 10Ohm
R12,R13 = 1.8kOhm, 2W
R14 = 2.2kOhm
R16 = 4.7Ohm
R17,R35 = 6.8kOhm
R19 = 5.6kOhm
R21 = 33kOhm
R22 = 8.2kOhm
R25,R26 = 18Ohm
R27 = 1Ohm, 1 W
R28 = 10Ohm 1W
R29 = 2.2kOhm, 2W
R32,R40 = 4.7kOhm
R33,R43 = 15kOhm
R38,R39,R45,R48,R51 = 22kOhm
R41 = 1MOhm
R42 = 10MOhm
R44 = 2.7kOhm
R47 = 150kOhm
R49 = 820kOhm
R53 = 47kOhm
P1 = 1kOhm trimpot, top screw adjustment
C1,C5,C7,C8,C9 = 1nF 1%, 63V, polystyrene, 7.18mm pitch (LCR Components type EXFS/HR 1000pF ±1%)
C2,C3,C11,C13,C16,C18,C31 = 100nF 10%, 50V, X7R, 0.2’’ pitch
C4 = 10µF 10%, 63V, MKT, 15mm pitch
C6 = 150pF 5%, 500V, silver mica, 5.9mm pitch (Cornell Dubilier type CD15FD151JO3F)
C10,C12,C14,C20,C32 = 10µF 20%, 50V, 5x11 mm, 2mm pitch
C15 = 10nF 10% 100V, X7R, 0.2’’ pitch
C17,C19,C33 = 1µF 20%, 50V, 5x11 mm, 2mm pitch
C21 = 22µF 20%, 50V, 5x11 mm, 2mm pitch
C22,C24 = 100nF 10%, 250V, MKT, 4x10 mm, 7.5mm pitch (TDK type B32520C3104K000)
C23,C25 = 680µF 20%, 100V, 28mOhm @ 2.57A, 18x40 mm, 7.5mm pitch (Rubycon type 100ZL680MEFC18X40)
C26 = 100nF 10%, 200V, X7R, 0.2’’ pitch (Kemet type C330C104K2R5TA)
C27,C28,C30 = 100nF 5%, 400V, polypropylene, 15mm pitch (TDK type B32652A4104J000)
C29 = 470nF 5%, 400V, polypropylene, 15mm pitch (TDK type B32652A4474J000)
C34 = 100µF 20%, 10V, bipolar, 2.5mm or 3.5mm pitch, diam. 8mm max.
C35 = 2.2µF, 50V, 5x11 mm, 2mm pitch
L1 = 22µH, Micrometals type T130-2 ring core, max. 20x40mm. Wire: 200cm of 1.5mm/AWG15 enameled copper
D1,D2,D11,D13,D14,D17 = 1N4148
D3,D8,D9 = 1N4007
D4,D5,D10 = BZX85C18 SB00018/E1, 18V/1.3W zener diode
D15,D16 = BZX55C68-TR, 68V/0.5W zener diode (alternatively, NXP type BZX79-C68)
D6 = MUR120G (200V, 1A)
D7 = BAV21 (250V, 250mA)
D12 = LED, green, 3mm
T1 = IRFI4020H-117P
T2 = TIP122G
T3,T4,T6,T7,T9,T10,T11,T12 = BC547C
T5 = BC557C
IC1 = AD8031ANZ
IC2 = IRS2092PBF
IC3 = MC7805CTG
IC4 = MC7905ACTG
IC5 = MC7812CTG
K1,K2,K3,K4,K5 = Faston spade connector, PCB mount, dim. 6.35x0.81 mm, 0.2’’ pitch
JP1,JP2 = 3-pin pinheader, 0.1’’ pitch, with jumpers
RE1 = relay, PCB mount, SPCO, 16A, 48V/5.52kOhm (TE Connectivity/Schrack type RT314048)
HS1 = heatsink, PCB mount, 2.6K/W, mounting pins spaced 1 inch (Aavid Thermalloy type 530002B02500G)
Heatsink for IC4/IC5/T2: 27x90 mm aluminum sheet, 2mm thick
Heatsink for IC3: 30 x 30 mm aluminum sheet, 1mm or 2mm thick
Isolation materials for T2,IC3,IC4,IC5 (TO-220 thermal pad + TO-220 bush)
6 pcs solder pin, 1.3mm diam.
1 pc DIP-16 IC socket
1 pc DIP-8 IC socket
Kit of parts incl. PCB 150115-1 (mono), excl. supply: Elektor Store # 150115-71
PCB # 150115-1, available separately and optionally
Ancillaries for Hypex SMPS400A400 PSU connection
1 pc JST VHR series 5-way straight case for PCB connector, 3.96mm pitch (RS Components # 820-1188, set of 5 pcs)
1 x JST VHR series 3-way straight case for PCB connector, 3.96mm pitch (RS Components # 820-1175, set of 5 pcs)
5 x JST cable set with crimp connectors at both sides (RS Components # 820-1135, set of 5 pcs)
3 pcs isolated Faston connector, female, 0.25’’ pitch
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