This 200W MOSFET amplifier circuit designed for single or mono audio channel application. You should build two similar circuits for stereo audio application. Build one first for performance testing to ensure that this circuit really wongking well with great audio performance.

The power supply used for this circuit is a symmetrical / dual polarity type. You need 4 amperes minimum of transformer with +/- 45V output. For stereo application, use about 8 amperes, although the 5A transformer is good enough . You may use the power supply circuit design on this post: 200W Power Amplifier using Transistor

200W MOSFET Amplifier PCB Layout Design

Bottom / Chopper PCB Design

Top PCB Design / Component Placement

Schematic Diagram:

Component part list:

PCB Layout:

Component Placement:

Take a note that this amplifier requires dual polarity power supply. Build the power supply using center tap transformer with output current 2A minimum and output voltage 30V, use about 6800 uF – 10000 uF electrolityc capacitors (elco). Good luck.

source: http://users.otenet.gr/~athsam/power_amplifier_35w_with_lm391.htm

Here the Amplifier Circuit Diagram:

Here the PCB layout:

About LM12:
The LM12 is a power op amp capable of driving +25V at? +10A while operating from +30V supplies. The monolithic? IC can deliver 80W of sine wave power into a 4X load with? 0.01% distortion. Power bandwidth is 60 kHz. Further, a? peak dissipation capability of 800W allows it to handle reactive? loads such as transducers, actuators or small motors? without derating. Important features include:

• Input protection
• Controlled turn on
• Thermal limiting
• Overvoltage shutdown
• Output-current limiting
• Dynamic safe-area protection

Download the LM12 datasheet from below link:
[wpdm_file id=32]

The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4 ohm load and 38W into 8 ohm with 0.1% THD+N from 20Hz-20kHz.

LM3886 Amplifier Specifications:

Maximum Output Power   : 68W RMS - 108W Peak
THD                    : %0.03 at 60W
SNR                    : 110dB at 60 W - 92.5dB at 1W
PSRR                   : 120dB
Protection Circuitries : DC /AC Short circuit protection and thermal protection
Output Class           : Conjugate AB-A

The performance of the LM3886, utilizing its Self Peak Instantaneous Temperature (?Ke) (SPiKe?) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area (SOA). SPiKe protection means that these parts are completely safeguarded at the output against overvoltage, undervoltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks.

The LM3886 maintains an excellent signal-to-noise ratio of greater than 92dB with a typical low noise floor of 2.0uV. It exhibits extremely low THD+N values of 0.03% at the rated output into the rated load over the audio spectrum, and provides excellent linearity with an IMD (SMPTE) typical rating of 0.004%.

Download the LM3886 datasheet document:
[wpdm_file id=28]

Components list:

R1, R3 _________ 1K2 ohm
R2, R4 _________ 18 ohm
R5, R6 _________ 1 ohm
C1, C2 _________ 3u3 50V mini
C3 _____________ 22uF 16V
C5 _____________ 100uF 35V
C6, C7 _________ 220uF 10V
C10, C11 _______ 2200uF 35V
C4, C8, C9 _____ 100nF
IC _____________ TDA2009A
Heat sink

Circuit Specifications :

D.C. Input         : 8 ? 24V at 1 ? 2 A
Power output       : > 10W RMS /channel, 4 ohm load, 24V DC supply.
                     > 6W RMS /channel 8 ohm load 24V DC supply.
                     > 4W RMS /channel, 4 ohm load 12V DC supply.
S/N ratio          : > 75 dBA re. 10W output.
Frequency response : ~ 10 Hz to 50 kHz ?3 dB
Gain               : ~ 36 dB
Input level        : ~ 100 mV for full output

Circuit Works:
C1 & C2 are input coupling capacitors and block DC, as do C10 & C11 which are the output coupling capacitors, and C6 & C7 which block DC from the feed back loop. R1/R2 (and R3/R4) set the level of feed back.

The gain is equal to 1 +(R1/R2) = 68 or 37 dB. C8/R5 (and C9/R6) provide a high frequency load for stability where loudspeaker inductive reactance may become excessive. C4 and C5 provide power supply decoupling or filtering.

Kits:

The kits of this circuit is available at electronickits.com, you can order the kit there with online transaction.

Download 2x10W audio amplifier kit manual include the schematic diagram and the explanation:

10W Stereo Power Amplifier TDA2009A

1 file(s) 199.54 KB

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Download TDA2009A Datasheet Document:

TDA2009A Datasheet

1 file(s) 581.45 KB

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This document is the manual of 2x90W Stereo Tube Power Amplifier with EL34, model K4040 by Velleman. The document in PDF version contain of schematic diagram, part list, component guide, step by step how to build the circuit. This circuit is for advance hobbysts…

Stereo Tube Power Amplifier Features:

• Pure valve sound with high quality EL34 valves.
• High quality black and chrome housing.
• Chrome valve socket covers.
• Easy bias adjustment with LED indication.
• Removable bottom for easy access and service.
• High quality capacitors and components.
• Gold plated input and speaker terminals.
• Standby function.
• Soft start circuit for power transformer.

Stereo Valve Power Amplifier Specifications:

• 2 x 90Wrms in 4 or 8W.
• Up to 2 x 15Wrms full class A.
• Bandwidth: 8Hz to 80KHz (-3dB/1W).
• Harmonic distortion: 0.1% @ 1W/1KHz.
• Signal to noise ratio: >105dB (A weighted).
• Input sensitivity: 1Vrms.
• 115VAC or 230VAC / 500VA max.

Download the complete TUTORIAL of 2x90W Stereo Tube Power Amplifier with EL34 from the following link:

Stereo Valve Power Amplifier

1 file(s) 1.32 MB

Download Manual

Schematic Diagram:

Power Supply:

Component List:

It is a classic design of power amplifier 35 W using tube, with two EL34 in connection Push-Pull, by Siemens & Halske, with design date 03/24/1953 and code SV410 / 1. The amplifier worked from 1954 to 1989, whenever and went off, with an average lifespan of 15 hours a day. Showed no particular damage beyond the replacement tubes, resistors and capacitors, resulting from natural wear.

A significant change was the replacement of the rectifier device of lamp diodes. The only problem will be for those who try their construction, will be the output transformer (applies to all tube manufactures), because the code is not helpful. Can be replaced with a conventional output transformer suitable for EL34. During the construction, it is need (applies to all circuits respectively) enough electronic experience and attention to the high voltage, electric shock risk.

source: http://users.otenet.gr/~athsam/Power_amplifier_EL34.htm

This is 20 watt audio amplifier circuit design which use IC LM1875 as main component. This circuit is simple and very easy to built. For stereo channel, you need to build the two same circuits which will amplify the both of audio channels (right and left channel). Dual polarity / symmetrical power supply required for this kind of amplifier.

The LM1875 is a monolithic power amplifier offering very low distortion and high quality performance for consumer audio applications.

The LM1875 delivers 20 watts into a 4 ohm or 8 ohm load on 25V supplies. By using an 8 ohm load and 30V supplies, over 30 watts of power may be delivered. The amplifier is designed to operate with a minimum of external components. Device overload protection consists of both internal current limit and thermal shutdown.

The LM1875 design takes advantage of advanced circuit techniques and processing to achieve extremely low distortion levels even at high output power levels. Other outstanding features include high gain, fast slew rate and a wide power bandwidth, large output voltage swing, high current capability, and a very wide supply range. The amplifier is internally compensated and stable for gains of 10 or greater.

Download LM1875 datasheet for 20 Watt audio amplifier reference project:

LM1875 Datasheet

1 file(s) 12.00 KB

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