Ampli Mosfet Simple



DIY Solid State Hi-Fi Audio Projects

A mixed collection Solid State Do-It-Yourself (DIY) audio projects. The projects include class-A power and headphone amplifiers and RIAA phono preamplifier projects. While most of the projects are very simple, they are typically operating in Class-A mode and will require a very robust and clean power supply for good hi-fi audio results. Questions and discussions about Solid State and Hi-Fi audio are welcome in the DIY Solid State forum.
Last update: 19 September 2015

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DIY Solid State Hi-Fi Audio Projects

The DIY solid state projects are listed in chronological order. For other types of projects, use the navigation on the left.

Ampli Mosfet Simple
DIY JFET MC Pre-Preamp Kit - 19 Sept 2015 NEW! KIT Low Voltage
This is the Boozhound Laboratories JFET Moving-Coil (MC) Pre-Preamp Kit. The MC pre-preamp kit consists of a PCB, standoffs, the circuit parts and building instructions. The builder will need to provide a 12-24VDC power supply, an enclosure and miscellaneous hardware like connectors and switches. The kit uses 2SK170 JFET transistors and comes with fabulous vintage Russian military paper-in-oil (PIO) capacitors. Mark uses 9V batteries for the power supply and is very pleased with the results.
DIY JFET RIAA Phono Preamplifier Kit - 10 July 2011 KIT Low Voltage
Mark has put together the JFET Phono Preamp Kit from Boozhound Laboratories. The RIAA phono preamp kit consists of a PCB, the circuit parts and detailed building instructions. The builder will need to provide a 24VDC power supply, a chassis and miscellaneous hardware like connectors and switches. The kit uses JFET transistors and comes with fabulous vintage Russian military paper-in-oil (PIO) capacitors. Mark reports that this is his best phono preamp so far!

First, take the 13007 Transistor. Tin the wires of 13007 Transistor. The Tin process makes the. Simple Mosfet DC Amplifier IC AP500A used to promote the class, at the end of a Hitachi-Featured K1058/J162 as supervisor. Figure in the K1, K2 for the button-switch, K1 can be L, R-channel input signal swap; K2 is used shutdown disconnect the load and avoid impact.

Le Pacific JFET RIAA Phono Preamplifier - 10 July 2011 Low Voltage
Mark has built several RIAA phono preamplifiers using the popular Le Pacific phone preamp circuit. The Le Pacific preamp circuit is based around a couple of JFET transistors and has sufficient gain for use with MM phono cartridges. An additional gain stage is available to accomodate MC phono cartridges. The RIAA circuit is powered from a 24VDC supply and the current draw is low so a battery supply can be used. The JFET Phono Preamp Kit from Boozhound Laboratories reviewed about is based on the Le Pacific circuit. This is a simple circuit that sounds real good. Be sure to use matched transistors.
DIY 12AU7 (ECC82) / IRF510 Headphone Amplifier - 12 April 2010 Low Voltage
Rogers has built an improved version of his popular and simple low voltage 12AU7 / IRF612 Headphone Amplifier (5 Aug 2008). The new version allows novice builders to experience assembling and listening to their own headamp. The headphone amplifier is similar to the previous version in that a single 12AU7 (ECC82) vacuum tube is used for voltage gain and an IRF510 MOSFET follower stage is used to provide current to drive demanding headphones. The hybrid tube and MOSFET amplifier operates off a 12V SLA battery so there are no high voltage concerns. The main difference from the original version is that a LM317 regulator is used as a CCS to bias the MOSFET into class-A operation instead of a load resistor. The project includes PCB image files and can also be built on a protoboard. This simple headphone amp can be built for about $40-50.
Jean Hiraga's Super Class-A Amplifier - 8 February 2009
Dan has put together another a great looking Class-A amplifier following Jean Hiraga's 'Super Class-A 30W' design published in the old French magazine 'L'Audiophile'. Dan used the original driver transistors, but due to the unavailability of the original power transistors, Toshiba 2SA1943 and 2SC5200 transistors are used. The transistor change allows for an increase in the rail voltage which results in more power (58W measured). Dan reports that Jean Hiraga's deceptively simple and pure Class-A circuit topology delivers great sonic results.
DIY Class-A IRF610 MOSFET Headphone Amplifier Project - 30 June 2008 Low Voltage
Here is a simple headphone amplifier that uses an external CD-ROM for the enclosure. The circuit topology is a single-ended Class-A amplifier stage with an active load. The output device is an IRF610 MOSFET and a LM317 regulator is used as a constant current source (CCS). The sonic results are surprisingly good for such a simple design.
Jean Hiraga's - Le Monstre 8W Class-A Amplifier - 12 January 2008
Dan has put together a great looking amplifier which is based on Jean Hiraga's popular article 'Le Monstre' (The Monster). Dan has used the original PC board layout, transistors and JFETs noted in the article. However, he did make some changes to the power supply. Instead of a battery, Dan uses a regulated power supply.
DIY Class-A 2SK1058 MOSFET Amplifier - 18 November 2006
Mark has put together a very simple MOSFET amplifier that he fashioned after a single-ended (SE) tube amplifier. The amplifier uses a single 2SK1058 MOSFET in a very simple class-A single-ended (SE) amplifier design with a low parts count. Power output is very low, just a few Watts, but the sound is incredible.

Superseded DIY Solid State Hi-Fi Audio Projects

Mosfet Amplifier Circuit

The following DIY solid state hi-fi audio projects have been superseded by a more up to date project page.

  • Class-A 2SK2221 MOSFET Amp - 4 July 2007 - superseded by Class-A 2SK1058 MOSFET Amplifier
  • 12AU7 (ECC82) / IRF612 Headphone Amp - 5 August 2008 - superseded by 12AU7 (ECC82) / IRF510 Headphone Amplifier
This two circuits used to switch ON Or Off any DC load after delay:
First: Off after delay.
  • When S1 pressed, the capacitor is charged to Vcc and the mosfet saturate and the bell will loud (you can change the buzzer with any load you want).
  • After S1 is released the capacitor start discharging through R1, when the capacitor voltage reach certain value the mosfet blocks the current and the load switched off.
_ The blocking voltage change from transistor to another, for exemple 2Sk3070 when the gate voltage reach 2.1V it blocks the current. so the function time is when the voltage decrease from vcc(12V) to 2.1.
_ To calculate the time you can use this formula ( V = V0 * e^(-t/RC) ) or the Capacitor Discharge Calculator script tool HERE:
  • V (Threshold Voltage: the capacitor discharge value, for 2SK3070 2.1V)
  • V0 (Initial Charge Voltage: Vcc in our exemple 12V)
  • R (the discharge resistance Value (Ω) in the exemple 100KΩ)
  • C (Capacitor Value (F) in the exemple 100uF)
  • t (time of discharging that we want to calculate (s) )
  • we want (t): e^(-t/RC) = V/V0
  • -t/RC = Ln(V/V0)
  • t = -Ln(V/V0) * R * C
  • t = -Ln (2.1/12)*100000*0.0001
  • t = 17.42 s
  • So for R=100KΩ C=100uF the delay is 17second
Use the same equation to calculate the resistor or the capacitor value.
Second: On after delay.
The only difference is the transistor.
  • When S2 is closed the load switched On immediately (capacitor discharged).
  • When S1 is pressed (S2 closed), the capacitor is charged to Vcc and the mosfet saturate and Vds≈0, that means the transistor base Vbe≈0 which means the load is Off.
  • After S1 is released the capacitor start discharging through R1, when the capacitor voltage reach certain value the mosfet blocks the current Vds≈Vcc, the transistor saturate and the load switched On.
The same calculations are used to determine the On delay.Ampli Mosfet Simple

Mosfet Audio Amp Circuit

Thanks