DIY audio - do it yourself audio Projects.

DIY audio project or do it yourself audio project that gathering my interesting DIY projects such DIY preamplifiers and DIY power amplifiers.
All projects are designed and built by myself. Some projects are built for testing purposes only. Some were built and applied until the present which proves that it still works effectively even when used for so long.
I hope that this site could be useful in learning.

Trial no.01 voltage feedback amplifier for TH500i

10 Feb. 2012, by Thanaporn.

Because of that I'm building and design my new power amplifier project called TH500-i. It is actually be an integrated amplifier but I would initially design and build the amplifier part first. It is a 250w per channel power amplifier. Design approach is to bring together the advantages of a voltage-feedback circuitry and no global-feedback circuitry together. Therefore the feedback will be made only in the Voltage Amplifier Stage(VAS). The driver stage and output stage there is no feedback loop whatsoever. In order to reduce the interference and unwanted distortion cause by feedback voltage from the loud speakers.

TH-200SE DIY 100W power amplifier.

07 Feb. 2012, by Thanaporn.

This 100Wrms power amplifier was designed and construction since 1999. It was the first power amplifier I designed my own. It is the second power amplifier I built. The first one is power amplifier by kit which when I was a student. During that time the concept was to designed and constructed by pickup up my stock electronic parts as much as possible such as a transistor resistor capacitor and others. TH200-SE power amplifier design. The designed is like the most popular amplifier schematics. Differential amplifier circuit is used in the first stage. And of course for me a cascode circuit is used for this differential stage in order to increase linearity of the audio signal.

PT06 current feedback DIY preamplifier.

05 Feb. 2012, by Thanaporn.

PT06 is a preamplifier that was created in the same period of PT05 construction. I want to build this preamplifier to be a part of my main audio system. In fact an opamp based preamplifier is not my planned to build before. But after finding and Googled the LME49713H is a high fidelity opamp for high performance preamplifier. LME49713H are designed and manufactured by National Semiconductor (currently owned by Texas Instuments).It is an ordinary circuitry designed. Voltage gain of the PT06 preamplifier was set to about 12 times. The power supply unit of the preamplifier is a separate and independent of each other in order to reduce the cross-talk interference between channels.The dual 15VA Toroidal transfermers are used. Because of power supply is very important to sound quality. So same as PT05 the 2.1 voltage regulation power supply is used with the PT06.

PT05 DIY Preamplifier.

17 Jan. 2012, by Thanaporn.

PT05 is the upgraded version of PT03 preamplifier. The design is very similar. Designed to be used the independent power-supply circuit for left and right. Cascode circuit for the differential amplifier stage in order to reduce distortion and increase the linearity. Cancel the DC servo circuit. I have found that without DC servo brings the better sound quality and more natural. 2.1 stages voltage regulation power supply. The overall design. It is also 2-stage amplifier. The differential amplifier stage is a fully complementary transistor-based circuit and of course it runs in class A. The next stage is working with the first stage as well it is a fully-complementary. The cascode circuit is also in this place to improve linearity of the amplifiers. Cascode circuit requires a constant reference voltage biasing to make a cascode transistor on. We chose to use a transistor array as a voltage reference. Because it requires less current compared to the use of zener diode diode and LED and of course it has lower noise. The overall voltage gain is set to 12 times.The use of electronic devices.

PT03 DIY hifi pre amplifier

09 Aug. 2011, by Thanaporn.

PT03 is a Preamplifier that was designed to be successor of PT01 vacuum tube preamplifier. I intend to design it with mounted most electronic devices on the PCB except the transformer. So electronic components potentiometer and RCA jacks will be installed on the same PCB. PT03 is a transistor-based preamplifier.The amplifier schematic can be divided into 3 stages.

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