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Thread: Scale able class D 1250W UCD style and Non-UCD style - PCB Ready. Tested.

  1. #261
    Quote Originally Posted by Dzony_988 View Post
    Basic non ucd schematich... +-50V, IRFP250N,gate resistor 33ohm, 20uH, 1uH
    Get hot after 10 minutas heatsink is small an with fan 3x3 cm heatsink is cold.
    Output coil is hot (T106-2)
    In feedback wih 2.2nF coil is cold but amp distord, probably slow fets, with 4.7n, coil is warm but distorsion is little bit smaller, and 6.8n amp is without distorsion but coil is hot, about 60 deegress C.

    Thats why I asked what freq is with 820p, what is with 6.8n and what is with 10n!? Stewin, can you answer on it..
    Because its full range sound, probably freq is above 120KHz. Am I right?
    using the original component values and 820pf cap i got around 170KHz switching frequency. measured using a scope, the TL074 non-ucd have quite a bad square signal being feeded to IR2110 logic.

    on the other hand, i've been testing DETEX IRS900D and it seem to be better than the tl074 non-ucd. i even managed to get to switch at 800khz stable. no excessive heat at any component. well only the 12V regulator have the most heat output.
    using the original component value the irs900d have a switching frequency at 270-280khz. further testing are needed but i think it sounds better when switched at 480-500khz at there's less heat from the mosfet at that frequency.

    will post more result and signal pictures tomorrow.

  2. #262
    pascal Do you wrote about amp from site: http://www.diyaudio.com/forums/class...ml#post3116469 post #2174?
    Is it working good? I don't see any protection in this amp, Is it true?

  3. #263
    Quote Originally Posted by mkuczma View Post
    pascal Do you wrote about amp from site: http://www.diyaudio.com/forums/class...ml#post3116469 post #2174?
    Is it working good? I don't see any protection in this amp, Is it true?
    yes. that's indeed the irs900 that i'm talking about. to etch the pcb you could use the high resolution pdf that thienchay posted in this post and the overlay in this post.

    take note that there is some difference between the schematic and the pcb. for the corrected pcb refer to my post in the irs900d measurement at the end of the thread.
    at 280khz the input logic is square but over 400khz the logic to the high side isn't as square as it should be. i'm still trying some modification to reduce the dead time and improve the logic input.

    the original schematic should be good enough as it is and there's less part count compared to the tl074 non-ucd.

  4. #264
    quick update.
    been test both the tl074 non-ucd and the irs900d. the irs900d is a bit more robust and are not as susceptible to component error. i've even got the irs900d to work with 8-9uh when the non-ucd would just go unstable with that low inductance. the irs900d could also drive more mosfet without being too picky.

    maybe because of the higher switching frequency, maybe because of the better logic input. haven't tried increasing the switching frequency to the same 280khz as the irs900d yet, but the rest of the component is the same. mainly irfb5615, 27ohm gate resistor, 1n5819 gate diode, uf4007 driver diode.

    as both design are more or less stable with the test voltage, i'll be feeding them the operational voltage of ~65V next. will update more about my finding later.

  5. #265
    very nice and long thread, I am tempt now to make this small and neat amplifier after reading this thread for days.

    but witch PCB is correct? please guide me

  6. #266
    diysmps Senior Member
    Join Date
    Dec 2010
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    Kenya
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    470
    Quote Originally Posted by AutoclassA View Post
    very nice and long thread, I am tempt now to make this small and neat amplifier after reading this thread for days.

    but witch PCB is correct? please guide me



    Irs 900 or class ab amps?

  7. #267
    diysmps Senior Member
    Join Date
    Oct 2011
    Location
    Kuala Lumpur, MY
    Posts
    586
    i have correct pcb and build 3 pcs irs900D without error, with long post you need to read the entire post at least half of the page starting with irs900D, different with non ucd is IRS900D have good logic input and high efficiency module. with same supply let say +- 60vdc, irs900D can beat non ucd module at same psu.

  8. #268
    Greetings previous Mr. Norazmi,

    I want to build a Class D Power Amplifier for Speaker 2x18inch encourage or 4x15 'inch. do you think the power class D which one suits me the raft? I have never before assembling the power class D and I really do not understand the power of this, I ask the scout to make a very good power.

    I've read that you created thered but I'm still confused for the best that I want to do.

    greetings.

  9. #269
    hi guys...
    i'm builting this amplifier(ucd stule)and i want to add a clip indicator circuit...
    can you suggest me a circuit?
    my power suplly will be 2x60 volt...

  10. #270
    i'm trying to make the ucd style amp but i have a problem...
    it's not working and i have 20 volts dc at the outpout...but when i unplug the power transformer the amplifier starts to play for some seconds with a lot of distortion....
    can you help me to make my amplifier work?
    instead of uf4001 i used ba158....
    my power supply is 2x35 volt and it's only for testing reasons...
    the voltage will be 2x60...
    Last edited by panos123; 07-10-2014 at 09:57 AM.

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