LM Series IC's

MillerLiteScott
MillerLiteScott Posts: 2,561
edited September 2008 in DIY, Mods & Tweaks
PE has some Overture Audio LM3886T, LM3886TF and LM4780 on sale. I do not know how good they are but I am sure Ben would know.

LM3886T $7.34
LM3886TF $7.68
LM4780 $16.26

Scott
I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
Post edited by MillerLiteScott on
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    I like the LM3886. It is a mono chip capable of producing 50 watts at 8ohms, or 68 at 4 ohms given a 28vdc power supply. I used 34vdc from an Accurian amp PS, and I sine wave tested to 100 watts at 4 ohms. The TF version has an insulated tab that makes mounting to a heat sink a breeze. You can get the PCB's from Brian at chipamp.com. Brian is a cool dude. I can get the LM3886T's for just under $4 each. I have not used the 4780 yet;)
    Ben

    Edit
    The LM4780 is a stereo version of the LM3886. I prefer two mono chips for performance, and mostly heat dissipation.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited September 2008
    I did some objective testing of the LM3875 which is basically a slightly lower power version of the LM 3886.See post#3. http://www.polkaudio.com/forums/showthread.php?t=71781

    The measurements indicate that it has respectably low distortion below about 30 watts or so,but then rises very quickly above that.I verified this subjectively as it sounds quite good within its power limits,but if driven hard it doesn't overload gracefully.(ie definately no soft clipping circuit used.)


    IMO theyare best suited for easy 8 loads or multi amp active setups.

    I would like to substiude an LM3886 in place of one the 3875's in my chassis for listening and measurement comparison.
    Testing
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    I drove mine hard. I had 10 chips on hand so blowing one wasn't going to hurt my feelings, but I would recommend paralleling them for a 4 ohm load;) A big heat sink is key.
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited September 2008
    ben62670 wrote: »
    but I would recommend paralleling them for a 4 ohm load;)
    Sure but only if the transformer has sufficient wattage so it can source enough current to operate 4 chips instead 2.
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  • fredv
    fredv Posts: 923
    edited September 2008
    Did anyone try this http://dogbreath.de/Chipamps/ThreeResAmp/ThreeResAmp.html ?
    Looks like very low cost for entertainment :-)

    -fredv-
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    fredv wrote: »
    Did anyone try this http://dogbreath.de/Chipamps/ThreeResAmp/ThreeResAmp.html ?
    Looks like very low cost for entertainment :-)

    I'll save that link, and play with it!
    Ben
    BTW I love PTP:)
    Your tosh tranies are stiil here for you;)
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • fredv
    fredv Posts: 923
    edited September 2008
    Hi Ben,

    No worry, I don't think I will need the trannies any time soon :-)
    I bought some GC and PS boards from a fellow diyaudio member. There will be 2 spare LM 3886TF included. The 3 resistors amp is in order shortly :-)

    -fredv-
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    fredv wrote: »
    Hi Ben,

    No worry, I don't think I will need the trannies any time soon :-)
    I bought some GC and PS boards from a fellow diyaudio member. There will be 2 spare LM 3886TF included. The 3 resistors amp is in order shortly :-)

    Brian?
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • Systems
    Systems Posts: 14,873
    edited September 2008
    fredv wrote: »
    Did anyone try this http://dogbreath.de/Chipamps/ThreeResAmp/ThreeResAmp.html ?
    Looks like very low cost for entertainment :-)
    Thats the classic GC circuit and is what I used but with a PC board.His hard wired version looks pretty good.
    Testing
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    Testing
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  • fredv
    fredv Posts: 923
    edited September 2008
    ben62670 wrote: »
    Brian?
    Yes, Brian's board, some boards are soldered with parts. I shall receive the whole batch next week. Then you guys can suggest what can I do with all the stuffs :D

    -fredv-
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