Optoisolated gate drive Class D Amplifier

[Experimentonomen]

Next on the agenda is to try to make a better looking and electrically improved power stage to see if i can get rid of or atleast minimize that ringing seen in the speaker output waveform. I'm also gonna see if i can clean up the manhattan-board alittle as its a bit of a disaster atm from all the experimenting and trying things out.

Also it is unfortunately impossible to completely restore this thread back to the original until i've done more on the board past what it is in the first post, but i've brought back what i can, and i'll redo what videos i can.

 

[cowboybob]

Thanks for returning, Experimentonomen!

 

[4pyros]

Yes thanks for bring it back. I no longer feel cheated. LOL
Did you cook a sub and take vid?
Cant wait for rev 2.

 

[Experimentonomen]

I havent shot a new woofcook vid yet but i do have a vid of the aftermath from the previous woofercooker + some off camera stuff:

 

[cowboybob]

Thanks, man. Good stuff...

 

[Experimentonomen]

New woofer cooker video up in post three.

 

[audioguru]

Your woofer sounds awful because its voice coil is hitting the magnet structure because it is missing an enclosure.

 

[Experimentonomen]

So? Your missing the point. The reason i run a small woofer in free air is because i dont want the neighbours, my landlord and the police kicking my door in for beeing too loud while i do a power output test, yes i know i can use a dummyload but a purely resistive load is not always a good substitute for an actual speaker, and yes i know a freeair woofer also doesent show the same impedance curve as it would in a box, but its still alot closer than a power resistor can ever dream of.

 

[audioguru]

I have never blasted a woofer like that but I think its voice coil is jumping out of the concentrated magnetic gap which makes its impedance too low. Which overloads the amplifier.
Amplifiers have their power output quietly tested driving a non-inductive resistive load. Then they are listened to so that oscillation or other problems caused by the actual inductance and capacitance of a speaker is heard or not heard.

When I worked for a pro-sound manufacturer and played the system in the demo room at 1800W RMS into two 18" sub-woofers nobody complained because it sounded and felt good, not awful.
Our best amplifier was linear and produced 900W RMS into 8 ohms per stereo channel. Its guarantee said, "No questions asked and it is replaced if it ever fails". Many were sold and none ever failed. I was asked to test a competitor's amplifier to see if it produced its rated power. It didn't, it smoked instead.

 

[Experimentonomen]

My amplifier is NOT complaining about any kind of overload, as the mosfets used are rated at 47A continous(DC) and over 100A peak so i do not have any problems with overload. If anything my dinky lil 150VA or so power supply sags a few volts when i push 40 volts peak into a 4 ohms load.

Well a PA manufacturers demo room is something completely different to a domestic second floor rental apartment.

 

[Experimentonomen]

Cleaned up the prototype alittle:
https://i.imgur.com/cRkvfEO.jpg

I really need a camera with better sound:

 

[audioguru]

I haven't heard that song since about 30 years ago. By the Police? Sting?

 

[Experimentonomen]

Phil Collins.

 

[audioguru]

Phil Collins looks much older than me today but he is 6 years younger than me.

 

[cowboybob]

New woofer cooker video up in post three.

What fun !!

Did you create the file used for the cook?

 

[Experimentonomen]

No i dident, its Analog Pussy - Death Roll.

 

[Experimentonomen]

A tiny lil update:
https://i.imgur.com/HiApMug.jpg
https://i.imgur.com/X7M6v2N.jpg
https://i.imgur.com/LavAeMm.jpg
https://i.imgur.com/sTQnFWR.jpg

More to come.

 

[cowboybob]

I am woefully behind on my knowledge of current music .

Next on the agenda is to try to make a better looking and electrically improved power stage to see if i can get rid of or atleast minimize that ringing seen in the speaker output waveform. ...

Didn't see it (is it audible?). What's your plan?

<EDIT> Just saw your new pics. Starting to look pretty clean! Do you think your new arrangement(s) will help with the ringing?

 

[Experimentonomen]

Only time will tell.

 

[cowboybob]

Now that I think about it, I did notice a couple very brief 5 - 10hz "rings" in some of your vids...