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:
1 pcs. 10 USD / PCB pcs.
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 - I will add a subtitle as soon as possible but most likely next month:
TEST GX400A - YouTube
TEST GX400B (inclusiv THD test si calcul Slew rate) - YouTube
For more details please contact me via private messaging diyaudio.com or via email: donpetru@gmail[dot]com
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:
1 pcs. 10 USD / PCB pcs.
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 - I will add a subtitle as soon as possible but most likely next month:
TEST GX400A - YouTube
TEST GX400B (inclusiv THD test si calcul Slew rate) - YouTube
For more details please contact me via private messaging diyaudio.com or via email: donpetru@gmail[dot]com
Attachments
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I'll take 8 PCB's and the two already built unit
I will take eight (8) PVB's at $9.00 US Dollars each. That comes to $72.00
US Dollars. I will also take the two (2) built units at $75.00. Hence, the total
comes to $147.00 US Dollars plus shipping to the United States of America.
Le me know how much the total will be. Take care and thanks for the offer
to DIYAUDIO users.😀
I will take eight (8) PVB's at $9.00 US Dollars each. That comes to $72.00
US Dollars. I will also take the two (2) built units at $75.00. Hence, the total
comes to $147.00 US Dollars plus shipping to the United States of America.
Le me know how much the total will be. Take care and thanks for the offer
to DIYAUDIO users.😀
mrsavage, I sent you a private message (check the private message box).
Two (2) built units cost 2 x 75 = 150 USD. At the moment I have one unit assembled with MOS-FET and one assembled with BJT.
Two (2) built units cost 2 x 75 = 150 USD. At the moment I have one unit assembled with MOS-FET and one assembled with BJT.
Change my order to 10 PCB's and no pre-built PCB's
Please change my order to 10 PCB's and no pre-built PCB's. The total would
be $90.00 plus shipping to the United States of America. Let me know
what the shipping would be. Take care and thanks.🙂
Please change my order to 10 PCB's and no pre-built PCB's. The total would
be $90.00 plus shipping to the United States of America. Let me know
what the shipping would be. Take care and thanks.🙂
10 PCB's GX400 = $90 + $35 shipping = $125 (Ship with Romanian Post - is the same with Post Office or U.S. Mail - see: USPS.com - package will arrive in 2 ... 3 weeks).
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.😕
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.😕
@mrsavage, I attached here the files that you need. Check and PM. And sorry for the delay.
At this time there are only 10 pieces available PCB GX400.
At this time there are only 10 pieces available PCB GX400.
You want to say completely assembled sets? And one set, it means from your point of view, two pieces PCB fully assembled? I understood well ?!
If yes, then you want GX400 with BJT or MOSFET (GX400A or GX400B)?
At this point, I have assembled one version with MOSFET and one with BJT, and I have left 6 pieces PCB. If you wish, I can assembly two sets (this means assembly four pieces PCB) if you agree to pay in advance for that.
By the way, one fully assembled set consists of two pieces GX400 = 150USD (75USD / pcs) + shipping cost (depend on delivery address and courier company).
If yes, then you want GX400 with BJT or MOSFET (GX400A or GX400B)?
At this point, I have assembled one version with MOSFET and one with BJT, and I have left 6 pieces PCB. If you wish, I can assembly two sets (this means assembly four pieces PCB) if you agree to pay in advance for that.
By the way, one fully assembled set consists of two pieces GX400 = 150USD (75USD / pcs) + shipping cost (depend on delivery address and courier company).
From this moment I don't have any PCB GX400.
So, thank you to those who bought the PCB's.
Now, I have only two fully assembled units: one version with MOSFET and another version with BJT. Each version costs 75USD.
So, thank you to those who bought the PCB's.
Now, I have only two fully assembled units: one version with MOSFET and another version with BJT. Each version costs 75USD.
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