GX400 - 400W Audio Amplifier - Made in Romania

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donpetru

donpetru

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Joined 2007
#1
I have developed a new prototype audio amplifier where I try to mix simplicity with performance as well. So, I wanted to build an audio amplifier to provide the best performance in a price as low as possible and be an alternative observable to other audio amplifiers as well.
I would say, the GX400 is the most solid DIY audio amplifier (with fewer electronic parts) if will be used quality electronic components and the key electronic components of the diagram are sorted.
Some of these performances are shown in table amplifier characteristics of the project.

Relating to construction and operation of the GX400 audio amplifier I would like to say:
- GX400 amplifier has the advantage of automatically enter a state of MUTE if one fuse blows for some reason;
- To contact TEMP can attach a temperature sensor, such as a thermostat (the protection is indicated by led PROTECT);
- if the MUTE header is shorted, then the audio amplifier state will be MUTE;
- GX400 amplifier has DC protection to protect the acoustic enclosure for DC voltage that could arise for various reasons at the output amplifier (the protection is indicated by led PROTECT);
- I did not include a reverse polarity protection voltages (very carefully when connecting the plus and minus voltage power supply);
- the SIG and PEAK leds I made in the simplest way possible. If you are carefully calibrated (especially the PEAK LED), then this led may very well signal when the amplifier is overloaded;
- I recommend sorting 2SA970 transistors on the input and the output power transitors.

Discussions in the romanian language arise here:
KIT102.4 = GX400 - Amplificator Audio Hi-Fi 400W - Comunitatea Tehnium Azi
and discussions in the english language can be run here, in this thread.

Since the project size exceeds the possibilities of attachment of this forum, I invite those interested to download the project from the web link above (you must be a registered user you can download it).

So, I wait for yours reviews.

Best Regards
 
#2
Donpetru,

Thank you for your post and your willingness to share your project.

For non-Romanian speakers, registration is a bit awkward, would you be prepared to simply present the schematic, either in simple format or complete, as an attached image here for people to easily view?

Appreciated,

Hugh
 
#4
The maximum pdf file size that can be loaded on this forum is 195.3 KB but my project is over 1Mb. If anyone is helpful to increase the load limit per file special for me, with the greatest pleasure I upload project file here.
Otherwise, please visit the above web link by selecting the bottom forum option of language viewing: "English".

Regards
 
#6
Hi ,
I have resized files, from project 🙂
Regards Alex.
 

Attachments

  • GX400 SCH.pdf
    GX400 SCH.pdf
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  • GX400 TEH DATA.pdf
    GX400 TEH DATA.pdf
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  • GX400 ALL.jpg
    GX400 ALL.jpg
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  • PCB BW.pdf
    PCB BW.pdf
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Last edited:
#7
donpetru said:
So, I wait for yours reviews.

Best Regards
Click to expand...

OK.

???? running 4 pair IRF's directly from a a non-buffered (driverless) 10ma VAS ?

Both CCS's are thermally compensated , but a standard 2Q CCS offers much better PSRR and comparable tempco. To decouple the CCS's ground reference will improve things further.

No degeneration on input pair ... tough to match, Offset quite possible.

Work on that Vbe , IRF OPS's have a very small bias "window" to obtain proper idle current. Nice set of MJE15034/35 drivers would go a long way. Unless you would prefer the run that VAS at 30-40mA.

OS
 
#10
@ostripper, initially I was thinking to realize 2Q CCS and not transistor + 2 diode, but instead of two diodes I used transistor + diode, performance of the two types of CCS are very close to maintain constant current when the voltage stages amplifier is changes. If you are sorted well transistors on the amplifier input and output stage, it will be very small offset (utmost 20mV). I not preferred to increase the polarization of the current VAS stage amplifier, because I don't observed a significant performance improvement (heats more VAS amplifier stage).

@jam, the gate rail capacitors (39pf) are necessary to fill, well, the role of the output amplifier coil (coil, which in this case, I have not used it).

@Art M, my project is a theoretical one to be put into practice (already started to be made ​​by a user from my forum). Certainly will need one or two complete revisions to complete this project. So, their powers are results of spice simulations we have done.

Regards
 
#11
GX-400

donpetru said:
@ostripper, initially I was thinking to realize 2Q CCS and not transistor + 2 diode, but instead of two diodes I used transistor + diode, performance of the two types of CCS are very close to maintain constant current when the voltage stages amplifier is changes. If you are sorted well transistors on the amplifier input and output stage, it will be very small offset (utmost 20mV). I not preferred to increase the polarization of the current VAS stage amplifier, because I don't observed a significant performance improvement (heats more VAS amplifier stage).

@jam, the gate rail capacitors (39pf) are necessary to fill, well, the role of the output amplifier coil (coil, which in this case, I have not used it).

@Art M, my project is a theoretical one to be put into practice (already started to be made ​​by a user from my forum). Certainly will need one or two complete revisions to complete this project. So, their powers are results of spice simulations we have done.

Regards
Click to expand...

Are there some variations in design mentioned,,,,i need to know is this a 100% working prototype without hassels
 
#12
Is this PCB and schematic a working product i need to build it

donpetru said:
@ostripper, initially I was thinking to realize 2Q CCS and not transistor + 2 diode, but instead of two diodes I used transistor + diode, performance of the two types of CCS are very close to maintain constant current when the voltage stages amplifier is changes. If you are sorted well transistors on the amplifier input and output stage, it will be very small offset (utmost 20mV). I not preferred to increase the polarization of the current VAS stage amplifier, because I don't observed a significant performance improvement (heats more VAS amplifier stage).

@jam, the gate rail capacitors (39pf) are necessary to fill, well, the role of the output amplifier coil (coil, which in this case, I have not used it).

@Art M, my project is a theoretical one to be put into practice (already started to be made ​​by a user from my forum). Certainly will need one or two complete revisions to complete this project. So, their powers are results of spice simulations we have done.

Regards
Click to expand...
 
#17
Sorry , missed generated by error typing .
Of course , only BLAMELESS Amplifier is corect version .
This type of amplifier ( BLAMELESS ) have a very little distortion
Greetings and you have great audition this project ( GX400 - last revision ) .
 
#18
Bill of Materials and Schematric foir the BX400 Amplifiers

Since I purchased several of these PCB's, I need a Bill of Material and a better
schematic diagrams for the two versions of this amplifier. Please post BOM and
larger schematics for this amplifier, so I can build these PCB's.
qILE2BYsylJiDhQ844DCxC9Z4xS8qbqDiMA5lQTKsfHVyiNzhpS4MsCUUtUUe3ylsdUIQwgWkDw5gHiERgZcLbT0CSPNDKshPyKZ48WIWQA2qbhIuIGpDYAIoI6RSHOUZ0QBQQh46NCgDJufBU+m1MAzhtakJVVIgKnlYxgiLICQ0Yo50bxghCabdFDIAGeUc0scM3iz1CVbvHLNF0XAIIklSEAUEAA7
 
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