The IRFP460 is quite a useful device, but the datasheet gives its maximum power dissipation as 250W. The circuit only shows two of them. You will need a few more for the sort of power levels you are talking about.
Another question is - why so much power in one amplifier?You might want to read this article:
http://sound.westhost.com/articles/pwr-vs-eff.htm
Another question is - why so much power in one amplifier?You might want to read this article:
http://sound.westhost.com/articles/pwr-vs-eff.htm
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I know its important to add more devices for PA
but I want to know first could this design working without smoking ?
The basic idea is OK. Have you looked at the LME49830? It is specifically designed to drive MOSFETs.
I'm worried about the single pair of output devices. It looks like a potential smoke generator to me. I would at least one more pair in parallel. To be sure, make it four pairs in total.
Remember that at full power, your amp will be putting out about 300W in heat, so get a big heatsink.
I'm worried about the single pair of output devices. It looks like a potential smoke generator to me. I would at least one more pair in parallel. To be sure, make it four pairs in total.
Remember that at full power, your amp will be putting out about 300W in heat, so get a big heatsink.
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This is a quasi complementary output stage.
If you use the Gamnut topology, the clipping behaviour is probably much more better.
Check out therefore this thread:
http://www.diyaudio.com/forums/soli...h-pull-pull-like-gamnut-whats-right-name.html
the simplified schema you will find about post #1
If you use the Gamnut topology, the clipping behaviour is probably much more better.
Check out therefore this thread:
http://www.diyaudio.com/forums/soli...h-pull-pull-like-gamnut-whats-right-name.html
the simplified schema you will find about post #1
hmm, and how are you getting the heat away from the devices.
the Junction Case temperature resistance is 0.45 ohm.
if you have a infinite heatsink and no losses between the heatsink and the device it would be possible to remove roughly 150 watts of heat from the device.
in that case the junction would get over 90 degrees hot.
in the real world thats inpossible.
with a big heatsink and a proper conenction 75 watts of heat is possible per mosfet.
so want high power, get more mosfets.
in any case, read this:
Project 117
1.5KW amp and he uses 10 pairs of transistors.
I'd say that has a reason
the Junction Case temperature resistance is 0.45 ohm.
if you have a infinite heatsink and no losses between the heatsink and the device it would be possible to remove roughly 150 watts of heat from the device.
in that case the junction would get over 90 degrees hot.
in the real world thats inpossible.
with a big heatsink and a proper conenction 75 watts of heat is possible per mosfet.
so want high power, get more mosfets.
in any case, read this:
Project 117
1.5KW amp and he uses 10 pairs of transistors.
I'd say that has a reason
schemtaics for amplifiers that can come arround so much power beyond P117 and the LME designs can be found in the internet very eassily .... most of them will sound also very good
The problem is that none of the schematics on this power have protection enough to protect the amplifier form it shelf ( suppose that the user will do all properly )
To be able to produce any amplifier for PA use anything more than 200 ( real watt ) you nead to study many Pa amplifier schematics understand what/ why/ how and many others arround the protections of the amplifier .....If you ever manage then go ahead ....other than that anything you built above 200W and used for PA will eventually blow
The schematic of one PA amplifier is only the 10 % of the job implementation and protection is the rest 90% .... obviously duarbility and reliability is more importand than power in PA bussines .
Sorry to say that this is a waste of time since all that has been allready told to you in many other "power hungry"threads you ve made ...but there you go ... once more ]
smoky regards
sakis
The problem is that none of the schematics on this power have protection enough to protect the amplifier form it shelf ( suppose that the user will do all properly )
To be able to produce any amplifier for PA use anything more than 200 ( real watt ) you nead to study many Pa amplifier schematics understand what/ why/ how and many others arround the protections of the amplifier .....If you ever manage then go ahead ....other than that anything you built above 200W and used for PA will eventually blow
The schematic of one PA amplifier is only the 10 % of the job implementation and protection is the rest 90% .... obviously duarbility and reliability is more importand than power in PA bussines .
Sorry to say that this is a waste of time since all that has been allready told to you in many other "power hungry"threads you ve made ...but there you go ... once more ]
smoky regards
sakis
Well pointed out. I only see a DC protection which will protect the speaker, not the amp... For something to survive any reasonable length of time in PA duty you need an input signal limiter, DC protection, VI limiters and overtemperature protection, at the very least.
ok, thanks
- you need an input signal limiter,
have an input signal limiter, its DSP input board
- overtemperature protection
yes have with 2 step fan control
- VI limiters
I think zener + diode in series should protect the fet for overcurrent ??
I've said it before and will say it again - a project like this is not to be undertaken lightly. The transformer needed will be similar to that found in a small arc welder, for instance.
It is most unlikely that you will be driving a single speaker with 1kW. Rather build four 200W amps and drive four speakers. Much easier. Or if you insist on having a big rig, build two 400W amps (the difference between 800W and 1000W is about 1dB).
It is most unlikely that you will be driving a single speaker with 1kW. Rather build four 200W amps and drive four speakers. Much easier. Or if you insist on having a big rig, build two 400W amps (the difference between 800W and 1000W is about 1dB).
no zeners and diode will not be enough
sophisticated vi limmiters might
and then Vas needs to be guarded also at this power
then pcb will be twice as tricky
distribution of power /earth in such a large scale cannot be done easy
hear this .... nobody here is trying to kill your diy spirit... just to explain to you that your task is not easy and requires various types of knowledge
( another example is that for a behringer EP4000 there is a team of engineers working for quiet long time ( i also have details available if you want ) trying to do this and prevent every available aspect of error or performance versus cost ) what makes you think that one person can produce similar results in lets say 6 months time ?)
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Have a look at the datasheet for the LME49830. It has a circuit with PCB layout. While this circuit will not put out 1kW, it will make a lot of noise. The output devices are good for 150W each, so it will go north of 100W with ease. If you add additional MOSFETS, 200W or 400W is within reach.
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