Best Audio Chip for 2x14W speakers

Discussion in 'The Projects Forum' started by jj_alukkas, Oct 30, 2011.

  1. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
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    Hello everybody,
    So I have a very old Sony Hifi Stereo.. from 83' I guess.. Its got a tape player, fm,mw,sw123 and all those outdated stuffs and was in my attic since past 5 or more years.. On checking it today, nothing of it seems working except radio.. amplifier chip is blown, tape side is useless and the mw/sw stuffs are not used in our country which is fully discrete analog type with bundles of wires running over.... All Im interested in is the 3A 12V powersupply which can give a little less than 17VDC, working Bass-Treble-Balance-Volume Controls, 2 analog Vu meters, the cabinet itself and the Full range stereo speakers of 2x14WRMS.
    This unit wont be used by anyone unless it has some good functions, so thought of adding a USB/fm board and replacing the amplifier. The blown amp chip is NEC UPC1185 which is extinct and is a stereo amp in 1 chip looking similar to the LA4440 package. The speakers specify 14W max on each box and has an impedance of 3.2ohm each. power supply is 12v 3A giving near 16-17V when unloaded.
    So my question is would 2xTDA2030 be a better option or would a single LA4440 be a better choice. I have a spare LA4440 stereo board, but I havent tried it with this speaker. I tested it with a single TDA2030, but i doubt if the audio quality is a bit low.. Im not sure if its even due to the speaker quality, but since its an original Japan Sony Speaker, Im confused. Thats why I'm asking for an expert suggession. I would prefer a bit more audio quality over 3-4W of extra speaker power per channel as I am going to integrate a USB reciever. Or would you suggest any other easy available chips for this power ratings and supply voltage. I would prefer 1 or 2 chip solutions, trying to avoid additional transistors. Also I donot wish to change the power supply which is single channel. Thank you in advance. I have another similar thread asking abt TDA2030, but this is a different project, so please dont think its a duplicate. Thank You.
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    A speaker rated at only 14W peak is rated at only 7W RMS which is very low. It might survive 7W for only a moment.

    The TDA2030A has a minimum supply of 12V when its output power is almost nothing. It usually uses a 32V to 36V supply.

    A few years ago there were over 76 car radio audio amplifier iCs available. Today most are not made anymore but NXP Semi has many new ones.

    Try a TDA2009A stereo amp IC. With a 13V supply its output power into a 3.2 ohm speaker is about 5.5 Watts when barely clipping per channel. Digikey has 334 available today for $2.93US each.
     
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    A typical auto integrated amp like the TDA2003 is a good choice. The TDA2003 is target for single rail power supply about 15V ballpark.

    http://orzparts.com/index.php?main_page=product_info&cPath=28&products_id=373
     
  4. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    thank you for your reply. I checked the datasheet, but tda2003 is 10w @ 2ohms and 6w @ 4ohms... Whereas 2030 is 14w @ 4ohms and my speakers are 14w 4ohms and i think 2030 is newer than 2003 and are available as 50cents single channel boards in my locality. Would there be any quality diff between the two? Response curves show better low end response on 2030..
     
  5. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    WOW

    1) the power ratings are MAXIMUMS the amp can deliver for the given conditions

    2) the 2030 has higher ratings because it is for higher supply voltages, which determine maximum power

    3) the 2003 is actually "newer" than the 2030. I did the design for both when working at fairchild back in 1978 - 1980. The 2003 was a newer version of the TDA2002, done several years prior. We did the 2003 about a year after the 2030 came out. BTW, both were functional equivalents of the SGS Thompson parts of the same name.

    " my speakers are 14w 4ohms "

    That would be the MAXIMUM rating they are designed to be mated with, you can safely use anything that does not exceed those numbers.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    1) You said the speakers say "14W Max" on the box. Then they are rated at 7W RMS each because "max" power is peak power which is simply double the RMS number.

    I have some RadioShack Minimus 7 speakers (cast metal enclosure with woofer and tweeter). They are stamped "40W max". Each 4" woofer is stamped "5W Korea".

    2) The datasheet for the TDA2030A shows that it produces 14W into 4 ohms when the power supply is double the voltage you have.

    3) A TDA2003 produces 6W into 3.2 ohms when barely clipping when the power supply is 14.4V.

    A TDA2005 is a stereo amplifier IC with spec's similar to the older TDA2003 mono amplifier IC. It produces 6.4W into 3.2 ohms when barely clipping per channel when the power supply is 14.4V. If you bridge its two channels then it produces 17.6W into 3.2 ohms when barely clipping when the power supply is 14.4V.
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    It would be much quicker to help ,if you list all the amplifier chips that you know for 100% sure you can get some items of. Then we can help you deciding which one that is the best for your application
    I will Also add. With two TDA 2003 in bridge pr channel. You should be OK
     
    Last edited: Oct 31, 2011
  8. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
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    5
    @bountyhunter
    Oh my God! Great to meet you sir!! This is why AAC is such a great forum!!
    As regarding the chip, 2003 is available easily here. So I think I should be settling for it as the best option. Thanks a lot!

    @Audioguru
    Thank you for that great info! It is printed 7WRMS 14WMax on both boxes, so I thought it meant 14W was what it was rated for. Thanks for correcting me. And you were right. The original extinct chip was NEC UPC1185 rated at 10W, so I guess it should be 5W+5W within the safe limits of the speaker. Even I was thinking at first how can a 10W chip power a 14W+14W system. Now it explains everything. So actually 2030 is more than twice powerful as the 2003 for a 4ohm speaker, only when supply voltage is 24-28V, right? Boy, thats a lot of info! I have another question, different from my subject, just to know its idea. I have a Pioneer Hifi with some 26cd changer. The 2 boxes have been rated '100W max' 8ohm.. so does that mean its rms is only 50W?? I am now running each box using 1 bridged LA4440 IC on 18VDC. So how much power should I be getting from the boxes? 20W? Thank You.

    @t06afre
    Most of the 2k series chips are available here and the most common I have seen are are the 2003 and 2030. And according to what Audioguru and bountyhunter said, my speakers are just 7WRMS, so 2 bridged 2003 might stress it too much. I think one is fine!
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    You can bridge a couple of 2003's, just don't run them at full volume.
     
  10. t06afre

    AAC Fanatic!

    May 11, 2009
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    How about you get two 2003 and try out both bridge or not it is often good to have some "reserve" in the amplifier. The data sheet have both as applications/schematics. I think the 2003 is a good selections given your supply voltage. Good luck with your project
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    Yes, and maybe the woofers can survive 50W RMS for a duration of only 1 second. The tweeters are very fragile and cannot withstand continuous power.

    The datasheet for the LA4440 shows that its max allowed supply is 18V. It clips at 20W and produces about 20W of heat so it needs a huge heatsink, a fan and maybe liquid nitrogen for cooling.
    20W is only a little less loud than 50W because our hearing's response to loudness is logarithmic.

    Note that the little amplifier I am now listening to (I made it about 20 years ago) burns my fingers when I touch it because it was designed to drive 8 ohm speakers but now it is driving a 4 ohm speakers with nearly double the power and nearly double the heating.
     
  12. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Tsk. Tsk. Tsk. Thermal management! Slap some bigger heatsinks on the active amp parts, or add a small fan for forced air cooling. :p
     
  13. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
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    5
    Actually I built this one when I was in my 10th std in 2002.. Didnt know much then, but it still works, and yes it has a huge aluminum heatsink which I cut out from a square tubing :) I think I could make a soldering iron out of it then :D
     
  14. Audioguru

    New Member

    Dec 20, 2007
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    A real heatsink has fins so that it has a high surface area. A piece of metal made from tubing makes a poor heatsink.
     
  15. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    <Saturday Morning Smartass Mode>
    Semantics... A REAL heatsink is an infinite mass of silver thermally connected to the component.

    The closest real world affordable solution is a high thermal conductivity metal cut in such a way to expose massive surface area (fins/waves/etc)

    </Saturday Morning Smartass Mode>
     
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