In my opinion, class D amplifier is the largest. And is the only advantage.
Is efficiency. High voltage output makes him meaningful. Low voltage. Its performance is no better than that of class AB amplifier. Please refer to for the specific principle
https://www.diyaudio.com/community/...ss-d-is-class-ab-class-a.388305/#post-7074713
And how high the voltage output is. Will make class D exceed the meaning of class ab.
I think the output voltage sine wave + - 140V voltage is OK. And it is easy to implement.
We can use + -70v or + -75v voltage for power supply.
Use L30D architecture. That is, irs2092s + irfb4227 structure.
https://www.diyaudio.com/community/threads/l30d-irs2092-irfb-4227-iraudamp9-mydiy.280531/
Then use BTL.
It is easy to realize the output + - 140V PP sine wave. That is 280vpp voltage output.
And the distortion is controlled at 0.07%. This will be beyond any class single-chip amplifier design.
And it's very Tu
If anyone is interested, I will design L30D BTL 1000W 8R amplifier.
It may be the amplifier with the lowest distortion of 1000W 8R in the world at present.
Most of those small integrated circuits have more than 10% distortion, 50W 8R, 100W 4R.
For example, tpa3255 ma12070
If we are only satisfied with 50W 8R. 100W 4R (a single chip ClassD usually only indicates 4R power) then any class AB amplifier can easily achieve 50W 8R and 100W 4R
The distortion is less than 0.002%, such as mx50se.
That low-power class D amplifier is meaningless. It needs to convert the audio signal into PWM.
Then convert PWM into audio signal. In order to save 5 watts of electricity at 50W 8R power.
At 10 watts. Class D does not even save power than mx50se. Because I measured it.
Class d always maintains the maximum PWM output voltage.
ok We will only discuss class D now. So is anyone interested
Is efficiency. High voltage output makes him meaningful. Low voltage. Its performance is no better than that of class AB amplifier. Please refer to for the specific principle
https://www.diyaudio.com/community/...ss-d-is-class-ab-class-a.388305/#post-7074713
And how high the voltage output is. Will make class D exceed the meaning of class ab.
I think the output voltage sine wave + - 140V voltage is OK. And it is easy to implement.
We can use + -70v or + -75v voltage for power supply.
Use L30D architecture. That is, irs2092s + irfb4227 structure.
https://www.diyaudio.com/community/threads/l30d-irs2092-irfb-4227-iraudamp9-mydiy.280531/
Then use BTL.
It is easy to realize the output + - 140V PP sine wave. That is 280vpp voltage output.
And the distortion is controlled at 0.07%. This will be beyond any class single-chip amplifier design.
And it's very Tu
If anyone is interested, I will design L30D BTL 1000W 8R amplifier.
It may be the amplifier with the lowest distortion of 1000W 8R in the world at present.
Most of those small integrated circuits have more than 10% distortion, 50W 8R, 100W 4R.
For example, tpa3255 ma12070
If we are only satisfied with 50W 8R. 100W 4R (a single chip ClassD usually only indicates 4R power) then any class AB amplifier can easily achieve 50W 8R and 100W 4R
The distortion is less than 0.002%, such as mx50se.
That low-power class D amplifier is meaningless. It needs to convert the audio signal into PWM.
Then convert PWM into audio signal. In order to save 5 watts of electricity at 50W 8R power.
At 10 watts. Class D does not even save power than mx50se. Because I measured it.
Class d always maintains the maximum PWM output voltage.
ok We will only discuss class D now. So is anyone interested
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No, I just drank some green tea.
I find green tea refreshing. There is no way to sleep.
But it's great.
Many times. In a state of mental excitement.
Can have design inspiration.
In fact, I don't like to pay attention to these things most of the time. I prefer to go shopping.
But recently our place has been closed. You are not allowed to go out. There seems to be some infectious disease. This made me suddenly interested in DIY again.
Unfortunately, I found. DIYer is now much lower than it was ten years ago. I should save them.
👽
L25, L6, L20SE, L20V9.2.
I don't remember many more.
These are all analog amplifiers. You can go to solid state Find a lot of people to play inside
I hope can post here, if not please correct me.
As I was told that LJMs amplifiers are best sounding amps out there and I have desire to build my own active PA system with profi drivers inside like R€F or ele€tro voi€e, I would like to ask for some advices.
I would like to achieve best possible sound without compromise like weight or power efficiency, like some manufacturers that make plastic boxes and D class amps.
Each driver in the box would run by separate LJM amplifier and would get signal from dsp module that would equalise sound for each driver separately, high,mid and woofer.
Amps aluminium enclosure should be on the back of speaker box and had rigorous cooling with fans.
I have seen there is LJM L50 500w amp that seems to be good fit for 12” 450w drivers and this system, lets say 2x L12 for high drivers with horn, 1xL50 for 12” mid and 2xL50 for 12” lower frequency.
If those amps dont have sufficient quality could go with less powerful system and use L20, L25 amps, first would order amps and replace them with factory active speaker amp and compare it with other that is not replaced.
Bass 18” would be added separate to system and its not need to make it.
My main question is how L50 compare with L20,L25 and other advices are welcome.
If ljm_ljm member here is person that stands behind those great amps I would appreciate to get your opinion about my concerns 🙂
I apologise if have post this in wrong place, I dont use those forums much.
As I was told that LJMs amplifiers are best sounding amps out there and I have desire to build my own active PA system with profi drivers inside like R€F or ele€tro voi€e, I would like to ask for some advices.
I would like to achieve best possible sound without compromise like weight or power efficiency, like some manufacturers that make plastic boxes and D class amps.
Each driver in the box would run by separate LJM amplifier and would get signal from dsp module that would equalise sound for each driver separately, high,mid and woofer.
Amps aluminium enclosure should be on the back of speaker box and had rigorous cooling with fans.
I have seen there is LJM L50 500w amp that seems to be good fit for 12” 450w drivers and this system, lets say 2x L12 for high drivers with horn, 1xL50 for 12” mid and 2xL50 for 12” lower frequency.
If those amps dont have sufficient quality could go with less powerful system and use L20, L25 amps, first would order amps and replace them with factory active speaker amp and compare it with other that is not replaced.
Bass 18” would be added separate to system and its not need to make it.
My main question is how L50 compare with L20,L25 and other advices are welcome.
If ljm_ljm member here is person that stands behind those great amps I would appreciate to get your opinion about my concerns 🙂
I apologise if have post this in wrong place, I dont use those forums much.
In fact, the power of the power amplifier is not so important.
Don't misunderstand me. It is believed that the high power amplifier will be better than the low power amplifier. This is wrong.
I think you can try l20. Or L25. The L50 is really powerful. But its performance is slightly lower than that of L25
Im thinking about high power PA system 1500w rms per cabinet that can cover audience of 1000 people with great sound and can be used in array setup to add more power and coverage .
I know there are some high end PA manifacturer that produce 400w speakers with stunnung power but didnt get too much deep into this stuff.
Its just a dream to make my own system that will sound very good, will try with L50 also if difference is slight because its easier to make everything and find speakers, also both L12 for high and L50 for mid and low could use same 50v power supply and have enough caps reserve between different frequencies.
Do you recomand switching or regular trafo power supply? And what think which amp is best for highs and what for mids and bass.
Also should buy from ali or you have some site, thanks.
I know there are some high end PA manifacturer that produce 400w speakers with stunnung power but didnt get too much deep into this stuff.
Its just a dream to make my own system that will sound very good, will try with L50 also if difference is slight because its easier to make everything and find speakers, also both L12 for high and L50 for mid and low could use same 50v power supply and have enough caps reserve between different frequencies.
Do you recomand switching or regular trafo power supply? And what think which amp is best for highs and what for mids and bass.
Also should buy from ali or you have some site, thanks.
If you are used for square movies. Maybe L50 can.
L50 is a BTL circuit. Be careful.
I generally recommend the use of ring transformers. It is difficult to guarantee the quality of the switching power supply.
I don't mean that the switching power supply can't work. But the switching power supply is good. There are also bad ones.
And it is not easy to judge. Most of the power of switching power supply is false data. And cannot be judged.
In fact, different amplifiers are selected. It is mainly determined by our use situation.
If it is used in the cinema. We need good reliability. I recommend l20se or l20v10
Actually, I'm not the best designer. There should be many better designers than me.
I'm just a good choice. There are too many design schemes. I just choose the more suitable scheme.
Choosing and giving up is more troublesome than designing. 😎
I also thought maybe better to use ring transformer or similar with few kw of power 220/36v ac and then 5m of 200A rated cable to speakers that will have rectifier and filter + amplifiers and cooling inside them.
Could use l20se for highs and l50s for 2*12”
Have ordered those 2, not sure if need order original mosfets right now, will try it first.
Why to be carefull about btl l50?
If think some other amp , or configuration would be better choice please correct me.
Most important is sound quality and reliability, yes👍🏻 Im looking for most clean, natural and detailed rich sound and believe it could sound much better then sterile sounding Dclass amps mostly used in systems like this today.
Mostly would be used in different events, cinema, conferences, poetry evenings, clubs and live concerts..
Depending on the need it could be hang in the air to cover up to 1000 people as line array
or used like ground stack and 1 or 2 cabinet per side for smaller events.
First would like to replace original amp on one of active high power speakers with LJMs💪and compare sound with other factory one.
If it doesnt meet expectations would probably give up, but if does an exciting journey awaits us, fasten your seat belts please,🛩 😄
Could use l20se for highs and l50s for 2*12”
Have ordered those 2, not sure if need order original mosfets right now, will try it first.
Why to be carefull about btl l50?
If think some other amp , or configuration would be better choice please correct me.
Most important is sound quality and reliability, yes👍🏻 Im looking for most clean, natural and detailed rich sound and believe it could sound much better then sterile sounding Dclass amps mostly used in systems like this today.
Mostly would be used in different events, cinema, conferences, poetry evenings, clubs and live concerts..
Depending on the need it could be hang in the air to cover up to 1000 people as line array
First would like to replace original amp on one of active high power speakers with LJMs💪and compare sound with other factory one.
If it doesnt meet expectations would probably give up, but if does an exciting journey awaits us, fasten your seat belts please,🛩 😄
Your speaker is a big project. But it's not as complicated as you think.
I think the performance of L25 is better than that of L50.
But the power of L50 is indeed larger.
As for which one to use. Maybe L50 is suitable.
Be careful not to short circuit the output.
Congratulations and well done on the LD15, LD20 and LD25. These appear to be fine boards with a great reputation. I'll use these now for anything around, 250w
LJM, I would love to see a 2000w into 4R board 🙂
LJM, I would love to see a 2000w into 4R board 🙂
Real high power amplifier. Analog circuits are required.
Class D cannot be used.
Class D is only digital power. Theoretically. Not actually. Many people have no practical experience.
How do all those cars class d manage it? There are some big RMS numbers being tested on the Wilston audio YouTube channel amp dyno?
Do you mean he is making it appear being tested at 8 or 4R, but secretly loading it up with half an ohm? That seems dishonest