PQFN 5X6mm Packaged N channel Power Mosfet in ClassD ...

[Tekko]

Use a 4 ohm power resistor dunked in a glass of water.

 

[savu]

yep but i also need to hear it ... oscilloscope images is not all. you need to hear the sound to see if it has good dynamics.

regards,
savu

 

[Tekko]

You can buy a cheap car woofer at walmart or radioshack or something.

 

[savu]

I live in Romania,
It's like the country of nobody.
we don't have radio shack or walmart.
we have stupid inhabitants and beautiful chicks.
regards,
savu

 

[Tekko]

Come to sweden 😉 We have cheap woofers here.😛😀

 

[luka]

lool

 

[savu]

i may be moving to Finland for some studies for the next 4 years.
nothing is certain in my world 🙂
regards,
savu

 

[luka]

lot of you go to finland, lol on that too

 

[ionutgaga]

I am using right now the original version with trough hole parts with the original pcb at 30V +/-.
it sounds good at 225Khz ...
but it misses dynamics on flac files.
have to test it to the limit but none of my friends will borrow a 1kw woofer for tests after they heard that i want to test this amp. 🙁
so i have to find a big woofer to test it to the limit.

1kw woofer for what?
You can use the resistance of a hob, adjusted to the desired value (2-8 ohm) and a 2 resistors divider to power the speaker. In this way, you can listen at low levels where the ear is more sensitive, and the amplifier operates at its limits.

 

[theAnonymous1]

You can use the resistance of a hob, adjusted to the desired value (2-8 ohm) and a 2 resistors divider to power the speaker. In this way, you can listen at low levels where the ear is more sensitive, and the amplifier operates at its limits.

I've done something similar in the past to test for hard clipping since I don't own a scope. I put a small sensitive speaker in parallel with the load resistor with a series cap on the speaker; this way I could listen for the higher frequency artifacts without the lower frequencies getting in the way.

 

[savu]

1kw woofer for what?
You can use the resistance of a hob, adjusted to the desired value (2-8 ohm) and a 2 resistors divider to power the speaker. In this way, you can listen at low levels where the ear is more sensitive, and the amplifier operates at its limits.

hello ionut

can you provide me a schematic of what you have described?
it would be very helpfull because i never tried such a thing

regards,
savu

 

[savu]

I changed the circuit to this and got twice the switching frequency:

hy tekko,

can you also provide component values for me to do a spice simulation of the thing?
if the rersults are promissing i will ask Marce to redesign a part of the board and also fit a small module with unbalanced imput and ballanced output opamp.

regards,
savu

 

[Tekko]

Here u go:

 

[savu]

Tekko,
does this actually work in reallife or it's just a simulation?

regards,
savu

 

[Tekko]

That is what i had on the prototype board. 460kHz switching frequency.

Except i used IR2010 and IRF540.

 

[savu]

Thanks,
i'll send the the data to marce and see if he has time to modify the design.
regards,
savu

 

[marce]

I will find the time😉

 

[savu]

Hi marc,

i have a friend who will help me design custom chip packages in express pcb (i know it's a shitty software but it is free so i can use it at work also).

again thanks for you're effort
regards,
savu

 

[savu]

The PCBs have arrives.

regards,
savu

 

[qusp]

are there going to be any more of these?