Weekend chip amp project

Wardsweb
Wardsweb Posts: 936
edited January 2010 in DIY, Mods & Tweaks
Here is my latest completed amp project. It is a LM38886TF "chip amp". It has cleaner lines than my last chip amp which used an LM375TF.

LM3886TF1.jpg

LM3886TF3.jpg
Post edited by Wardsweb on
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Comments

  • strider
    strider Posts: 2,568
    edited January 2010
    Very nice work, as always.

    I'd be interested to hear your thoughts on the 3875 vs the 3886 after you get some time with the new guy. Where did you get the boards?
    Wristwatch--->Crisco
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  • Face
    Face Posts: 14,340
    edited January 2010
    That's a lot of heat sink for a chip amp.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Wardsweb
    Wardsweb Posts: 936
    edited January 2010
    The boards I picked up years ago from BrianGT over on DIYAudio. He now sells them on his website chipamp.com

    I'm all about excess, even in audio. The heat sinks I picked up on Ebay for almost nothing, so decided to use them.
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  • Face
    Face Posts: 14,340
    edited January 2010
    I didn't mean it in a negative way. I'd rather have too much than too little. :D
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • AsSiMiLaTeD
    AsSiMiLaTeD Posts: 11,728
    edited January 2010
    If you don't mind me asking, how much do you have in that?
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  • ShinAce
    ShinAce Posts: 1,194
    edited January 2010
    Is the PS regulated?

    Very nice. Looks like a beefy toroid as well!
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  • Wardsweb
    Wardsweb Posts: 936
    edited January 2010
    AsSiMiLaTeD wrote: »
    If you don't mind me asking, how much do you have in that?

    I didn't keep records but I would say about $150. The transfomer, PCB's with parts make up about $100. Misc stuff I had laying around.
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  • Wardsweb
    Wardsweb Posts: 936
    edited January 2010
    ShinAce wrote: »
    Is the PS regulated?

    Very nice. Looks like a beefy toroid as well!

    Here is the schematic

    ps.gif

    The transformer is 250VA and from parts express.
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  • MillerLiteScott
    MillerLiteScott Posts: 2,561
    edited January 2010
    Very Nice.

    I like the case. I need to start putting my projects in cool cases like that.

    Scott
    I like speakers that are bigger than a small refrigerator but smaller than a big refrigerator:D
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  • ben62670
    ben62670 Posts: 15,969
    edited January 2010
    Very nice clean job:)
    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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  • bikerboy
    bikerboy Posts: 1,211
    edited January 2010
    Nice clean layout and a huge transformer in this amp! I like the case, very cool with the rounded corners. I searched for this type of amp and didnt see a power rating. What kind of output do you expect out of something like this? I see all kinds of low(5-20 watts) output diy amps but I doubt I would be able to power a set of big polks with them. Am I wrong to think that? What speakers will you use with this amp?
    Main system: Lyngdorf TDAI 2170 w/ Pioneer 42" plazma-> Polk LSiM 703 w/Tivo, Marantz tuner, BRPTT: Nothingham Spacedeck-> Pioneer PL L1000 linear arm-> Soundsmith DL 103R-> SUT->Bottlehead ErosDigital: I3 PC w/ Jriver playing flac -> Sonore Ultrarendu -> Twisted Pair Audio ESS 9028 w/ Mercury IVY Vinyl rips: ESI Juli@24/192-> i3 PC server
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  • Face
    Face Posts: 14,340
    edited January 2010
    bikerboy wrote: »
    I doubt I would be able to power a set of big polks with them. Am I wrong to think that? What speakers will you use with this amp?
    I've used a few chip amps on my large Tannoy's with an issue, but I wouldn't attempt to hook one up to a large way tower, SDA, or something with a difficult impedance load.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Wardsweb
    Wardsweb Posts: 936
    edited January 2010
    bikerboy wrote: »
    Nice clean layout and a huge transformer in this amp! I like the case, very cool with the rounded corners. I searched for this type of amp and didnt see a power rating. What kind of output do you expect out of something like this? I see all kinds of low(5-20 watts) output diy amps but I doubt I would be able to power a set of big polks with them. Am I wrong to think that? What speakers will you use with this amp?

    The chip is rated for 68 watts. I'm under driving them, so I'm out putting about 50 watts per channel into 8 ohms.

    I have no intended use for this amp. I just like building things. I have a room of gear that I don't have in systems at the moment. Off the top of my head there is a Krell CDP, Shanling T100 CDP, Carver Silver 7t amps, Ampzilla Trinaural processor, Sumo pre, Teac X1000R R2R, LM3875 chip amp, this LM3886 chip amp, 2A3 stereo tube amp, 6DN7 tube amp, battery powered tube preamp, Pioneer SX3900 receiver and whole rack of SAE gear.
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited January 2010
    Bring it tomorrow brother.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • Face
    Face Posts: 14,340
    edited January 2010
    Face wrote: »
    I've used a few chip amps on my large Tannoy's without an issue, but I wouldn't attempt to hook one up to a large way tower, SDA, or something with a difficult impedance load.
    Sorry, that was meant to be without. I tried to power my custom three way speakers which dip down to 3ohms and they didn't sound good at all.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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