UCD 25 watts to 1200 watts using 2 mosfets

akraj · 2012-01-19 5:56 pm

hmmm.....I know it is comparatively complex but it includes end to end design; surely this is tested and will be stable. I was searching for sub amp so it will serve my purpose. HOwever, CPX do you have any working amp design? would be greatful if you can share that!

CPX · 2012-01-19 8:49 pm

There are a several working designs on this thread..if you want you can choose one..my amplifier also works and i have made lots of tests but i am still working on improuvements so i have no final schematic yet..

akraj · 2012-01-22 5:50 am

Okay CPX, what do you think about the JBL schematic? I will try to draw a PCB if this is praiseworthy

CPX · 2012-01-22 8:45 pm

That schematic is for low frequencies only..there are so many others you can use..

,what is your experience level..have you worked with switching mode power supplies before ?if so there you will be capable to use any schematic not just blindy copy one. :cheers:

manojtm · 2012-01-31 1:12 pm

Hi All

Now I will give my working design!!!!!!!!!!!!!!!
Its simple and good.Protection and all other things can added later

manojtm · 2012-01-31 2:20 pm

Hi All

In my schematic op-amp shows LM1458 its LM358. If you use LM1458 supply must be +12V & -12V

manojtm · 2012-01-31 2:33 pm

Everybody says that quality of the Class D amp is depending on freq.
Class D amp will work 60KHz to 500KHz but you should use proper supporting components.
The advantage of increasing freq. reducing the size of filter coil and capacitor

stewin · 2012-02-02 7:18 pm

hi manojtm did you use 500khz with irfp250 at +/-75vlts? did it work and what load did you use 8ohms 4ohms or was it stable at 2ohms ? thanks for sharing.

manojtm · 2012-02-04 12:00 pm

Hi stewin IRFP250 will not support 500KHz . 250KHz is Max. It will hot.125KHz is normal and stable @2ohm load

If you want to set 500KHz ,use IRFB4227

andrewlebon · 2012-02-06 2:43 pm

MOSFET RECOMENDATIONS

Hello
greetings can any one advice me which is most suitable mosfet for this amp
i am using IRF250 on50 volt dc rails
1 IRFB4103Pbf
2 IRFB 4227BPbf
data sheet of IRFB4103 shows Rds on@10 volts 139Mohm
data sheet of IRFB4227 shows Rds on@10 volts 19.7Mohm
can anyone advice me most suitable mosfet
warm regards
andrew lebon

savu · 2012-02-06 3:57 pm

IRFB4227 is best suited. You can use rails as high as 90v.
Regards,
Savu

CPX · 2012-02-06 5:19 pm

For andrewlebon :
irfb4227.Also try irfb5615

For manojtm .
Please measure THD and IMD of your design and post results here if you can.

Dimonis · 2012-02-06 7:17 pm

andrewlebon said:
Hello
greetings can any one advice me which is most suitable mosfet for this amp
i am using IRF250 on50 volt dc rails
1 IRFB4103Pbf
2 IRFB 4227BPbf
data sheet of IRFB4103 shows Rds on@10 volts 139Mohm
data sheet of IRFB4227 shows Rds on@10 volts 19.7Mohm
can anyone advice me most suitable mosfet
warm regards
andrew lebon

Catch

It's for rail up to +-65V
The "lightest" , I.e. prefered from the top.

Dimonis · 2012-02-06 7:26 pm

If you desire up to 90V per rail
These will suite well.

Dwenson · 2012-02-07 5:01 pm

stewin said:
no i did not use clipping indicator but i am going to do so .on the over temp issue i used a 0.1 ohm resistor when i connect it the led does not light but when i disconnect it the led lights and relay does not go off . here is my part of the schema

whats the use of J10? when R34 and c39 are in parallen to ground? have you tested it on actual run?

andrewlebon · 2012-02-08 3:35 am

FINALLY WORKING

Hi
greetings can anyone guide me as its only my second sucessful d class amp
at last managed to make amp work outputs are IRF250N my supply is 50 volts
dc amp is sounding clear and powerful in 4 ohms load only problem is my output inductor after testing about 20 different cores finally managed to get cores which are luke warm on high volume testing on trying different cores of same
material with more and less turns sound quality changes more treble another core more bass how do i know which is best output inductor for me i cant get
t106_2 core here so i cant really tell what core will sound best can any one suggest where i can order t106_2 prewound 33uh inductor
warm regards
andrew lebon

Whortless · 2012-02-08 10:59 am

andrewlebon said:
Hi
greetings can anyone guide me as its only my second sucessful d class amp
at last managed to make amp work outputs are IRF250N my supply is 50 volts
dc amp is sounding clear and powerful in 4 ohms load only problem is my output inductor after testing about 20 different cores finally managed to get cores which are luke warm on high volume testing on trying different cores of same
material with more and less turns sound quality changes more treble another core more bass how do i know which is best output inductor for me i cant get
t106_2 core here so i cant really tell what core will sound best can any one suggest where i can order t106_2 prewound 33uh inductor
warm regards
andrew lebon

Hi,
There is something wrong in your application. This is not an ordinary ClassAB amp. Therefore you must not use wires from PCB to output mosfets. First correct this and mount the mosfets directly to PCB and then try your different output inductors again. There should be some difference. It is very difficult to say which inductor is best without any measured result.

BR

andrewlebon · 2012-02-08 12:33 pm

THANKS FOR REPLYING

Hi Whortless
greetings thanks for replying wires are for testing all suitable mosfets available with me till i get my IRFB4227 MOSFETS
warm regards
andrew lebon

Dimonis · 2012-02-08 1:18 pm

andrewlebon said:
Hi
greetings can anyone guide me as its only my second sucessful d class amp
at last managed to make amp work outputs are IRF250N my supply is 50 volts
dc amp is sounding clear and powerful in 4 ohms load only problem is my output inductor after testing about 20 different cores finally managed to get cores which are luke warm on high volume testing on trying different cores of same
material with more and less turns sound quality changes more treble another core more bass how do i know which is best output inductor for me i cant get
t106_2 core here so i cant really tell what core will sound best can any one suggest where i can order t106_2 prewound 33uh inductor
warm regards
andrew lebon

The cores that i see at your foto seem to be ferrite?
It's not good to make inductors on ungapped ferrite

.
You can make a gap in a Ring-core with a grinder , some thing about ~3mm . So it woudn't saturate.
Like this

stewin · 2012-02-09 9:52 pm

andrewlebon said:
Hi
greetings can anyone guide me as its only my second sucessful d class amp
at last managed to make amp work outputs are IRF250N my supply is 50 volts
dc amp is sounding clear and powerful in 4 ohms load only problem is my output inductor after testing about 20 different cores finally managed to get cores which are luke warm on high volume testing on trying different cores of same
material with more and less turns sound quality changes more treble another core more bass how do i know which is best output inductor for me i cant get
t106_2 core here so i cant really tell what core will sound best can any one suggest where i can order t106_2 prewound 33uh inductor
warm regards
andrew lebon

congrats andrew finaly you have it working. try to get e cores from old pc power supply and boil them in hot water . after separating them coil 30 turns and make sure you add 1mm gap using a tiny piece of old cd or dvd disc. BTW cool car stereo sony gt490

sad for me after like 4 months of my amp working it failed but i think it is tip 41 which supplies 12vlts to ir2110 which failed and caused the whole thing to collapse i was using 24ohms 3speakers each 8ohm speakers in series .

UCD 25 watts to 1200 watts using 2 mosfets

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