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VSSA Lateral MosFet Amplifier

Why 4? did plan to use more than one per chanel???

Will be 8A devices to drive 4 to 5ohms min speakers at +/-35VDC rails?

Marc

One ALF08NP16V5 per channel. Look it is simple, for Id=8A you need Vgs=6V, so at +/-38V PSU you get +/-32Vp on the output and that is 8Ap current. This device can do 8A continuos current within SOAR. So perfectly OK for one ALF08NP16V5 to drive 4 ohm at +/38V rails potential and you get out 128Wmax/4 ohm. ;)
 
One ALF08NP16V5 per channel. Look it is simple, for Id=8A you need Vgs=6V, so at +/-38V PSU you get +/-32Vp on the output and that is 8Ap current. This device can do 8A continuos current within SOAR. So perfectly OK for one ALF08NP16V5 to drive 4 ohm at +/38V rails potential and you get out 128Wmax/4 ohm. ;)

Who very interesting....i think i have little home work on eagle this evening...

Marc
 
Look Marc here's VSSA PCB preliminary. All three transistors to main heatsink, TO-126 will have 2 mm ceramic insulators, so very little capacitance to main heatsink (GND) and still enough heat dissipation. PCB fixed with these three screws only, each 2,2 mF/40V replaced with two 1mF/50V, etc. So you can get an idea ... :cool:
 

Attachments

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Look Marc here's VSSA PCB preliminary. All three transistors to main heatsink, TO-126 will have 2 mm ceramic insulators, so very little capacitance to main heatsink (GND) and still enough heat dissipation. PCB fixed with these three screws only, each 2,2 mF/40V replaced with two 1mF/50V, etc. So you can get an idea ... :cool:

Rhaaa lovely....will play with that if allow.

Marc
 
Sonny.. Regarding the tendency for the VAS to run thermally away, I have seen that a thermistor across the 470 Ohm rail resister can balance that out. I have currently two amplifiers playing, one bare stripped to simplest basic (like this) and one with everything. CCS's mirror's hawksford-casodes (input and VAS/Driver). Have not yet heard them in the same setup, but sometime during January I will... But first I need to cut some diamond for the CES.:)
 
Yes, good to stick to the plan here - 'very simple' means few parts. It means we are accepting some compromises. We can add complexity to deal with all sorts of things and improve the on-paper performance. In fact, you did that already with SSA.

What can be achieved with simple approach, where debugging is easy, pcb layout can be more optimal. Heck, can you make it simple enough for point to point so anybody can build it ?
 
VSSA MosFet Amplifier V1.1

Hi :wave:

VSSA schematic update. ALF08NP16V5 new double complementary output mosfet successfully tested, some design improvements and gate zener protection included. This is very good simple amplifier, highly recommended. :up:
 

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Hi :wave:

VSSA schematic update. ALF08NP16V5 new double complementary output mosfet successfully tested, some design improvements and gate zener protection included. This is very good simple amplifier, highly recommended. :up:

Hi LC,

need i some value tweakking to keep rail voltage to +/-35vdc as in first version (nice 625Va or 2x300va 2x25vac i have)

Marc