GX400 - 400W Audio Amplifier

donpetru

New member
Last revision GX400 amplifier is the result of a process of improvement and testing of an amplifier schematic who was wanted in the first to be a simple and compact amplifier, easy to build and with electronic components easy to find. I started polished schematic of the amplifier to be much better than revision no.1.

It is an audio amplifier that I tested with many types of transistors, including doublet and triplet in the output. As kind Dynacord companies chose to go with transistor amplifiers input its seemingly trivial (since the '80s), see famous series 2N3904/2N3906, I decided at some point, after I test amplifier with 2SC1815/2SA1015, to use 2N3904/2N3906. How legally hearing there was no difference, I said it's not bad to go on these transistors. And the result is very surprising.

Another important aspect of this amplifier is the fact that, especially in the input circuit, is required to match depending on the current gain of the transistors: N-CH with N-CH and P-CH with P-CH. This leads to easier sorting operation of the transistors, the more so as, if you buy transistors from the same lot, the characteristics of N-CH are very close to the N-CH, respectively P-CH with P-CH. Advantage that should be mentioned even more because there are many electronic hobbyists and professionals who do not have access to a large amount of electronic components to sort them.

Below I have posted schematics of the amplifier (GX400A - MOSFET version, GX400B -BJT version - both versions use the same PCB). You will notice a method of achieving a bias circuit, which is not the same in the two versions, because they need a bias BJT faster than with vertical MOS.

I attached a picture below with the PCB amplifier.

Purchase price of PCBs GX400 are as follows:

If you buy 1 pcs. = 10 USD / PCB pcs.

If you buy 2 pcs. = 9.5 USD / PCB pcs.


If you buy more than 3 pieces: 9 USD / PCB pcs

The shipping isn't included in the above prices.

Payment can be made via pay-pal at:

tehnium[dot]azi@gmail[dot]com

At this time I have two pieces fully assembled: BJT transistor version and a version with MOSFET transistors; the price of 75 USD / piece - see: GX400_foto2.jpg below.

I did some tests but in romanian language:
TEST GX400A - YouTube
TEST GX400B (inclusiv THD test si calcul Slew rate) - YouTube

For more details please contact me via private messaging here, on diysmps.com, or via email: donpetru@gmail[dot]com

Some images with GX400 and TA1000PS, in the same audio amplifier enclosure, posted by user @niksound on my website, I have attached below.

At this time there are only 10 pieces available PCB GX400.
 

Attachments

  • PCB - GX400 rev.2.jpg
    PCB - GX400 rev.2.jpg
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  • GX400_foto1.JPG
    GX400_foto1.JPG
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  • GX400_foto2.jpg
    GX400_foto2.jpg
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  • GX400 and TA1000PS _ photo1.jpg
    GX400 and TA1000PS _ photo1.jpg
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  • GX400 and TA1000PS _ photo2.jpg
    GX400 and TA1000PS _ photo2.jpg
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  • GX400 rev.2.1 & 2.2 - Parts List.pdf
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  • GX400A.jpg
    GX400A.jpg
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  • GX400B.jpg
    GX400B.jpg
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