F5 power amplifier

[Babowana]

Seeing the full power sign and square waves only, I think that merely 1X100ohms (3W) should be okay.

 

[ccschua]

I replace R5 R6 with 1x50R 5W. Looks like quite close to the square wave rating.

 

[kimarin]

Opps i wrote the wrong resistor value. When I wrote 1 ohm 2W i was thinking about R11 & R12 . I could use 2 in parallel and get 0.5 ohm 4w with metal films. But with R5-8 I can use 200 ohm 2W metal films , double it up and still get 50 ohm 8w. The reason for this is that I have alot of 2w metal films and wouldn't it be better to use metal film here instead of wirewounds?

 

[Spooky Electric]

Thank you, gentlemen.

 

[bobodioulasso]

I am somewhat curious about that modified feedback mechanism. Do I have this right? Merely 1x 100 ohms? Not 2x 200 ohms "so as to share the dissipation"?

I guess dissipation halves if resitor doubles.

 

[AndrewT]

I guess dissipation halves if resistor doubles.

no need to guess.

Pd = V * V / R = I * I * R = I * V

These formulae work for DC voltage and for AC voltage (Vrms)

 

[Dxvideo]

Me again (and again and again)...

Does 225VA 2x18v toroids enough per channel (for 8R spks) do you think?

 

[Spooky Electric]

Pd = V * V / R = I * I * R = I * V

I can't properly say why, but these formula reminds me a bit of my wife Lilly.

 

[bobodioulasso]

no need to guess.

Pd = V * V / R = I * I * R = I * V

These formulae work for DC voltage and for AC voltage (Vrms)

Such a knowledge is astounding!

 

[Babowana]

I can't properly say why, but these formula reminds me a bit of my wife Lilly.

 

[AndrewT]

Such a knowledge is astounding!

no,
it's taught in 3rd grade school science (in Scotland = 14 to 15year olds)

 

[R-K Rønningstad]

After all, Scotland is the second industrialised country in the world, so it is a small wonder. But for the rest of us, isolated by the channel...

 

[AndrewT]

Does 225VA 2x18v toroids enough per channel (for 8R spks)

225VA can support amplifiers between 112W and 225W of maximum total output power (economically).
A pair of National chipamps feeding 8ohm speakers from +-25Vdc will develop a maximum of ~32W+32W, 64W total.
The transformer is a bit extravagant, but it will certainly work.

 

[bobodioulasso]

no,
it's taught in 3rd grade school science (in Scotland = 14 to 15year olds)

Have you ever been taught what irony is?

 

[AndrewT]

off topic

Have you ever been taught what irony is?

obviously not, in which case your post contributed nothing to the discussion.

 

[bobodioulasso]

"We dont need no education.
We dont need no thought control.
No dark sarcasm in the classroom.
Teacher, leave those kids alone.
Hey, teacher, leave those kids alone!
All in all its just another brick in the wall.
All in all youre just another brick in the wall."

 

[Spooky Electric]

"You the people have the power, the power to create machines, the power to create happiness. You the people have the power to make life free and beautiful, to make this life a wonderful adventure. Then in the name of democracy let's use that power - let us all unite." Charles Chaplin

Doesn't that sound nice?

 

[Nelson Pass]

"The creations of our mind should be a blessing, not a curse
to mankind"

Einstein

 

[Nelson Pass]

Pd = V * V / R = I * I * R = I * V

I think Mike will recognize this.

 

[Dxvideo]

225VA can support amplifiers between 112W and 225W of maximum total output power (economically).
A pair of National chipamps feeding 8ohm speakers from +-25Vdc will develop a maximum of ~32W+32W, 64W total.
The transformer is a bit extravagant, but it will certainly work.

Thx Andrew! Im asking that because somebodies asking like "will a 400VA enough for this project" etc.. So I am consused..
Thanks again.