500W RMS PA Amplifier

[east electronics]

Sakis,
I don't know how you interpreted my comments.

Upto after that everything is completely different. I cannot seen any agreement nor similarity in our approaches to understanding what is going on !!!!

never said that our approach is similar .... i just tried to say that your calculations about thermals, efficiency , consumption , and power output are correct as usual ... ingenious is on the same path i think ....

i only wanted to point that real life commercial amplifiers are not constructed under the same calculations or aspects

your way of thinking might be more than hifi and a flawless design .... only its not actually possible to produce due to size and cost ....

 

[ingenieus]

I found this old thread that shows a low(ish) budget way of putting together a power supply for a big rig:

http://www.diyaudio.com/forums/solid-state/61422-arc-welder-transformer-used-power-amplifier.html

 

[AndrewT]

For 120V rails, output power is 3000W into 2 ohm,

The input power is about 6kW, so we are nowhere near the theoretical efficiency - as predicted by AndrewT.

where did you source input power = 6kW?
How can you arrive at a theoretical efficiency, when you appear to be quoting/stating real values?

 

[ingenieus]

where did you source input power = 6kW?

Oops - that is the peak value. For RMS, divide by 2. Both positive and negative rails supply that, but not at the same time. For purposes of efficiency calculations, do you add them together?

LTspice gives the peak values as 6,15kW into the 2 ohm load and 6,60kW for each rail supply. I calculate the efficiency as 47%. Am I getting this right?

 

[AndrewT]

Now that we have 3kW and 6kW reduced to half, tell us where you sourced that 3kW power input figure for a 1.5kW power output of a theoretical example ClassAB Push Pull amplifier?

 

[pankaj kashyap]

pcb

sir, have you its pcb or layout.

Tekko is on to something. A quick look on Yahoogle turned up this beast for $450 + shipping.

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Gemini XP-6000 Professional 6000W Amplifier

It is rated at 600Wpc into 8 ohm with 0.1% THD. That's a lot of power for the bucks.

Is it possible to beat this price in a DIY class B project?

You will need two 1000VA transformers:

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And two (no, make that that four) 0.3K/W heat-sinks:

An externally hosted image should be here but it was not working when we last tested it.

Lots of these:

An externally hosted image should be here but it was not working when we last tested it.

And don't forget these little suckers:

An externally hosted image should be here but it was not working when we last tested it.

By now we have blown the $450 and the shopping list is still quite long...

 

[AudioSan]

you don't realy get it do you?
the point was. at that price, this amp can't be build. even in high numbers by robots. just the trafo(s) will be more expensive then the whole amp.
BTW. the finnished amp is also only bull. there is no way it can deliver what they claime.

 

[jaycee]

don't forget he will want to use 2955/3055, tip31c/32c drivers because they're all cheap.
something for nothing. i always ignore such posts. this forum should probably have a policy on doing just that.

 

[mbah dukun]

Plise layout/bottom share