GX400 - 400W Audio Amplifier - Page 1
Forum section: electronics / general

author: donpetru
author_rank: Contributor
timestamp: June 24, 2014, 02:37:36 pm
content: 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 pcsThe shipping isn't included in the above prices. For calculating shipping fee please tell me in a private message the delivery address and the courier company with which you want to ship the package (eg. DHL or Romanian Post - Romanian Post is the same with Post Office or U.S. Mail - see: USPS.com).Payment can be made via pay-pal at:tehniumazi@gmailcomAt this time I have two pieces fully assembled: one version with BJT and one version with MOSFET. The price is75 USD / pieceor unit - see:GX400_photobelow.I did some tests but inromanian language- I will add a subtitle as soon as possible but most likely next month:For more details please contact me via private messaging viaeevblog.comor via email:donpetru@gmailcom

author: donpetru
author_rank: Contributor
timestamp: June 24, 2014, 02:41:35 pm
content: PCBs GX400 photos:

author: donpetru
author_rank: Contributor
timestamp: June 30, 2014, 04:35:12 pm
content: At this moment, have remained available only16 pieces PCB GX400.

author: donpetru
author_rank: Contributor
timestamp: December 11, 2014, 04:46:39 pm
content: At this moment0 pieces PCB GX400.It remained, only two fully assembled units: one version with MOSFET and another version with BJT. Each version costs75USD.