{"product_id":"discrete-class-d-amplifier-pcb-kit","title":"Discrete Class D Amplifier DIY Kit","description":"\u003cp\u003eThe Discrete Class D Amplifier DIY Kit is a complete, working audio power amplifier you build from fundamental building blocks — with no dedicated amplifier chip anywhere on the board. A 555 timer generates a ~188 kHz carrier, an LM393 comparator turns your audio into pulse-width-modulated pulses, an IR2113 gate driver and a pair of IRLZ44N MOSFETs switch the power, and a simple LC filter reconstructs it all back into clean, amplified sound.\u003c\/p\u003e\n\u003cp\u003eFeed it any 3.5 mm audio source, power it from a 12–20 V supply, connect a 4 Ω or 8 Ω speaker, and hear a Class D amplifier whose every stage you can point to. Labelled test points at each node turn the board into a live map of the signal chain — ideal for probing with an oscilloscope.\u003c\/p\u003e\n\u003cp\u003eThis is an intermediate-level kit combining through-hole (THD) and surface-mount (0805) components — a great project to practise both techniques on a single board.\u003c\/p\u003e\n\n\u003ch3\u003e📚 Prerequisites\u003c\/h3\u003e\n\u003cp\u003eYou'll need some previous knowledge to get the most out of this kit:\u003cbr\u003e\n► Ohm's Law and basic voltage-divider intuition\u003cbr\u003e\n► A feel for how capacitors charge and block DC\u003cbr\u003e\n► Some experience with SMD passives (0805) recommended — the through-hole parts are beginner-friendly\u003c\/p\u003e\n\n\u003ch3\u003e✨ Key Features\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eNo Amplifier Chip — Fully Discrete\u003c\/strong\u003e\u003cbr\u003e\nEvery stage is built from fundamental parts: a 555 carrier, a comparator, a gate driver and two MOSFETs. You get to see every stage that a commercial amplifier hides inside a single package.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e188 kHz PWM Modulator\u003c\/strong\u003e\u003cbr\u003e\nA 555 timer generates the carrier and an LM393 comparator continuously compares your audio against it, turning quiet line-level sound into high-speed pulses whose width follows the music.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eBootstrapped High-Side Gate Drive\u003c\/strong\u003e\u003cbr\u003e\nAn IR2113 half-bridge driver and a bootstrap capacitor solve the classic high-side MOSFET problem, switching an IRLZ44N half-bridge cleanly with matched dead time — no shoot-through.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAutomatic Standby\u003c\/strong\u003e\u003cbr\u003e\nA second comparator and a second 555 detect silence and put the output stage to sleep to save power, then wake the amplifier the instant music returns.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eA Complete Switch-Mode Lab\u003c\/strong\u003e\u003cbr\u003e\nLabelled test points at every node — Audio IN, carrier, PWM, switch node and filtered output — let you watch audio become pulses and be reconstructed again, stage by stage, on an oscilloscope.\u003c\/p\u003e\n\n\u003ch3\u003e🔧 Required Tools\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eSoldering iron\u003c\/strong\u003e — temperature-controlled (320–350 °C) recommended for the mixed SMD and through-hole parts.\u003cbr\u003e\n\u003cstrong\u003eDC power supply\u003c\/strong\u003e — 12–20 V (ideally current-limited), connected through the barrel jack.\u003cbr\u003e\n\u003cstrong\u003eAudio source\u003c\/strong\u003e — a phone, laptop or signal generator with a 3.5 mm output.\u003cbr\u003e\n\u003cstrong\u003eTest speaker\u003c\/strong\u003e — a 4 Ω or 8 Ω speaker you're happy to experiment with.\u003cbr\u003e\n\u003cstrong\u003eMultimeter\u003c\/strong\u003e — for continuity checks and verifying the 5 V rail and 2.5 V offset.\u003c\/p\u003e\n\n\u003ch3\u003e🔧 Recommended Tools\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eOscilloscope\u003c\/strong\u003e — turns this project into a full switch-mode lab: watch the 188 kHz carrier, see the pulse width breathe with the music, and observe the half-bridge switching node.\u003cbr\u003e\n\u003cstrong\u003eFlux, fine tweezers and a magnifier\u003c\/strong\u003e — make the 0805 passives and SOIC ICs far easier to place and inspect.\u003c\/p\u003e\n\n\u003ch3\u003e⚠️ IMPORTANT: Soldering Safety\u003c\/h3\u003e\n\u003cp\u003eSoldering irons operate at extreme temperatures (often over 300 °C), posing a severe burn risk. Always use a secure stand and never touch the tip. Ensure you work in a well-ventilated area or use a fume extractor to avoid inhaling fumes. Wear safety glasses to protect your eyes. Wash your hands after handling materials, particularly leaded solder.\u003c\/p\u003e\n\u003cp\u003eThis board also carries power: never exceed 20 V on the barrel jack (the limit is set by the IR2113 gate driver). At high output power the MOSFETs and the L7805 regulator can get warm — avoid touching them while the board is powered.\u003c\/p\u003e\n\n\u003ch3\u003e📦 What's Included\u003c\/h3\u003e\n\u003cp\u003e✓ PCB — high-quality printed circuit board\u003cbr\u003e\n✓ Electronic Components — 2 × 555 timers, LM393 comparator, 74HC14 Schmitt-trigger inverter, IR2113 gate driver, 2 × IRLZ44N MOSFETs, L7805 regulator, 22 µH inductor, and all supporting SMD and THD passives\u003cbr\u003e\n✓ Documentation — full assembly, circuit-theory and troubleshooting guide, plus a printable Assembly Print sheet\u003c\/p\u003e\n\n\u003ch3\u003e⚡ Technical Specifications\u003c\/h3\u003e\n\u003cp\u003e🔹 Topology: Discrete Class D (PWM switch-mode) — no amplifier IC\u003cbr\u003e\n🔹 Output: Mono (stereo input summed to mono)\u003cbr\u003e\n🔹 Supply voltage: 12–20 V DC via barrel jack (20 V max, set by the IR2113)\u003cbr\u003e\n🔹 Speaker impedance: 4 Ω or 8 Ω\u003cbr\u003e\n🔹 Switching frequency: ~188 kHz (555 carrier oscillator)\u003cbr\u003e\n🔹 Output filter: LC low-pass, ~34 kHz cutoff\u003cbr\u003e\n🔹 Key ICs: NE555 \/ LM555 ×2 · LM393 dual comparator · 74HC14 hex Schmitt inverter · IR2113 half-bridge driver · L7805 regulator\u003cbr\u003e\n🔹 Power devices: 2 × IRLZ44N logic-level N-channel MOSFETs (half-bridge)\u003cbr\u003e\n🔹 Component type: Through-hole (THD) + SMD (0805)\u003c\/p\u003e","brand":"Mixed Signal Development","offers":[{"title":"Default Title","offer_id":54285472563541,"sku":"K24013","price":38.9,"currency_code":"CHF","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0814\/1566\/8053\/files\/Discrete_Class_D_amplifier_Kit.jpg?v=1783274564","url":"https:\/\/mixedsignaldev.com\/products\/discrete-class-d-amplifier-pcb-kit","provider":"Mixed Signal Development","version":"1.0","type":"link"}