UCD 25 watts to 1200 watts using 2 mosfets

can you make some tests ?

1. IRFP 460 is different compare to Mosfets in original design

2. can you check about stray inductane or oscillation in output stage ?

3. Did you use right component value for Rail Voltage ?

4. Does this amp working, can you listen music ?

Finally,... is it possibile 2011 ucd design and schematic is a fake ?

or impossibile for stable working


regards
 
Ucd

I have examined the schematic and there are several issues which will cause serious problems.

1) There is no provision for any dead time
2) The MOSFETs shown are old, slow and are not suitable for high frequency switching
3) The gate resistors should be reduced to about 4.7 ohms and use IRFP4229 or some of the newer INFINEON MOSFETs which are superb.
4) The snubbers across the output MOSFETs reduce the resistor values to about 10 ohms.
5) Use 0.1mfd 100v chip caps ate the actual pins of the MOSFETs to ground (Upper Drain and lower Source)
6) Use a bunch of 0.1mfd 200v chip caps from +40v to -40v as close to the MOSFETs as possible.
7) The UF4004 bootstrap diode is too slow use a 35nsec 200v diode.
8) To keep the output offset low a servo MUST be used from speaker output to LM311 pin 2

Steve
 
I have examined the schematic and there are several issues which will cause serious problems.

1) There is no provision for any dead time
2) The MOSFETs shown are old, slow and are not suitable for high frequency switching
3) The gate resistors should be reduced to about 4.7 ohms and use IRFP4229 or some of the newer INFINEON MOSFETs which are superb.
4) The snubbers across the output MOSFETs reduce the resistor values to about 10 ohms.
5) Use 0.1mfd 100v chip caps ate the actual pins of the MOSFETs to ground (Upper Drain and lower Source)
6) Use a bunch of 0.1mfd 200v chip caps from +40v to -40v as close to the MOSFETs as possible.
7) The UF4004 bootstrap diode is too slow use a 35nsec 200v diode.
8) To keep the output offset low a servo MUST be used from speaker output to LM311 pin 2

Steve

Im a little confused because in Spain DIY Forum the amplifier should working very good..

can you add important changes in schematic and share your experience and knowledge with us ?
 
Last edited:
Im a little confused because in Spain DIY Forum the amplifier should working very good..

can you add important changes in schematic and share your experience and knowledge with us ?

In the kingdom of the blind the one-eyed are kings, but here we are in a two-eyed forum.

This amplifier in some cases can play loud music without overheating or destroying itself, but the design is full of pitfalls. In fact, those pitfalls make the result quite random, some units will work and some won't, depending on parts, etc... (too many parameters overlooked by the designer).

Electromagnetic interference will be quite high too.
 
In the kingdom of the blind the one-eyed are kings, but here we are in a two-eyed forum.

This amplifier in some cases can play loud music without overheating or destroying itself, but the design is full of pitfalls. In fact, those pitfalls make the result quite random, some units will work and some won't, depending on parts, etc... (too many parameters overlooked by the designer).

Electromagnetic interference will be quite high too.

Always complaining and criticizing other peoples work. its a good starting point no one has provided a better simpler class-d solution not even you, and yes, your good clever answers can only help so far.