If you want to have good output stage strength, I'd recommend 4 or 5 pairs of output power transistors. It is more than the 2 pairs necessary, but it keeps the amp alive, and has stronger drive for better bass.
On a 350W amp I built, I used 5 pairs of MJL4281/4302 and it was able to withstand a speaker going short to 0.9ohms when it blew at full volume, and sparks came from the speaker
and all it did was blow the mains fuse, with no harm to the amp. I've also driven it with less than 2 ohms under hard testing even though it's designed for 4 ohms.
4 or 5 pairs of big TO-3 or TO-264 makes a powerful amp and puts less stress on the transistors.
On a 350W amp I built, I used 5 pairs of MJL4281/4302 and it was able to withstand a speaker going short to 0.9ohms when it blew at full volume, and sparks came from the speaker
and all it did was blow the mains fuse, with no harm to the amp. I've also driven it with less than 2 ohms under hard testing even though it's designed for 4 ohms.4 or 5 pairs of big TO-3 or TO-264 makes a powerful amp and puts less stress on the transistors.
AF-2 Mosfet Amplifier
Anyone interested in buying the AF-2 Mosfet amplifier kit can email Jody at smi@netfront.net . I have recently purchased 11 of the kits from SME and they are quick to respond and ship. The PCB's look like new production and have acceptable components. They come without heatsink and are priced at $60 USD. Mark V Electronics used to sell these when they were in business.
John
Anyone interested in buying the AF-2 Mosfet amplifier kit can email Jody at smi@netfront.net . I have recently purchased 11 of the kits from SME and they are quick to respond and ship. The PCB's look like new production and have acceptable components. They come without heatsink and are priced at $60 USD. Mark V Electronics used to sell these when they were in business.
John
Vivek said:
Vivek, it's the same amp that djdan pointed:
http://users.otenet.gr/~athsam/power_amp_300w.htm
Only I designed a single-sided pcb layout.
john
p.s.sorry for the late response
It is not the amp schematic you posted. It is the Sound Master Electronics based in Hong Kong. It is still produced because of the performace of the design. It uses the Hitachi 2SK1058 and 1 SJ 162 lateral mosfet transistor. I know these transistors are not produced anymore. SME must have acquired an endless supply to include in these kits. Beware of the Reneses transistors as they do not sound as good as the Hitachi,s. I will post schematics and description if requested.
John
John
John, (Not the Baptist)
I did notice the schematic you posted in previous responses and that one resembles the TA-3600 that has many posts. But is not the same circuit design. 2 of these amps have been built and all the post about it are true. Read them all. There are plans to replace the drivers with MJ21194 with perforated emitter technology and a higher SOA. Other components are also to be replaced especially the TL071 with OPA927BP. Of course the Zeners are to be replaced with 6.8v as this OP amp chip operates with lower voltage for less disisapation.
Later,
John
I did notice the schematic you posted in previous responses and that one resembles the TA-3600 that has many posts. But is not the same circuit design. 2 of these amps have been built and all the post about it are true. Read them all. There are plans to replace the drivers with MJ21194 with perforated emitter technology and a higher SOA. Other components are also to be replaced especially the TL071 with OPA927BP. Of course the Zeners are to be replaced with 6.8v as this OP amp chip operates with lower voltage for less disisapation.
Later,
John
John,(Not the Baptist)
Those transistors are the gold standard in BJT's. The TA-3600 will not live using 4 N channel devices. They were included in the kit, but shorted due to the recommended power supply of 60 to 75 Volt +-. What is going to replace them is is the MJ21194. Much more robust and will live in that enviroment. With all that amp projects, time may prevail while trying to complete all of them.
Later Dude,
John
Those transistors are the gold standard in BJT's. The TA-3600 will not live using 4 N channel devices. They were included in the kit, but shorted due to the recommended power supply of 60 to 75 Volt +-. What is going to replace them is is the MJ21194. Much more robust and will live in that enviroment. With all that amp projects, time may prevail while trying to complete all of them.
Later Dude,
John
Made dual layered boards based on original layout.
