PA Discrete Class D Amplifier Schematic

kartino

Disabled Account
2005-02-14 3:41 am
This is working schematic. A Discrete Class D with 2 sets of mosfet at 90Vdc supply will give you enough power to drive 18" speaker at pretty loud.

Don't ask layout :)
Don't commercialize :D
Try if you like, as it is. Don't try if you doubt it.

Ltspice file is attached.

Regards,
Kartino
 

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kartino

Disabled Account
2005-02-14 3:41 am
The amp. All general discrete part can be found everywhere
 

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  • UcD2K Discrete.jpg
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mbogdan

Member
2016-10-03 11:28 am
Anyone know what schematic values need to be modified for a lower supply voltage. Say 2x40 - 2x50 volts.
I've built one of these, it doesn't work at these voltages.

So far, I've lowered R22 and R23 to about half value, but still i can't get it to work.
 
Wanted to try this, sim first.

Kartino,


I am trying to simulate your design in post 1, for the purposes of the sim leaving out the protection and font end buffers, and am getting a completely intractable -12 or so offset on the output. I am also using 80V supplies as I have several transformers that would give that voltage after rectification and filtering. I have experimented with different transistor types but that doesn't seem to matter, nor does the offset adjustment seem to do anything.


Would yo mind taking a peek at the schematic and see if I'm just blind to a mistake or if you can offer some suggestions on ridding the sim of the offset?
 

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  • UcD.asc
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mbogdan

Member
2016-10-03 11:28 am
I did buid one based on OP's schematic. I'm however having some problems with it.
At +/- 90V, it seems to distort at about 20-30W output power and when probing with a scope before the output filter, it seems I'm loosing modulation for a fraction of a second - while the amp distorts sound.
Can anyone point me on what to check to fix this behaviour?
 

kartino

Disabled Account
2005-02-14 3:41 am
I did buid one based on OP's schematic. I'm however having some problems with it.
At +/- 90V, it seems to distort at about 20-30W output power and when probing with a scope before the output filter, it seems I'm loosing modulation for a fraction of a second - while the amp distorts sound.
Can anyone point me on what to check to fix this behaviour?

Please post your schematic exactly as real kit