before I order my gainclone LM4780's....

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Audiophilenoob

Member
2005-05-07 6:10 am
NC
www.soundsolutionsaudio.com
  • #1
    Couple of questions...

    I'm going to build 2 gainclones... one will be a 4 channel LM4780 which I simply want to use to around 70 WPC (whatever the max is)... for midranges

    the other gainclone amp will be a parallel amplifier with 2 4780's per channel at around 100+ wpc paralleled for tweeters... for 4 ohm driving

    1. Should I buy 8 4780 kits then? I'm assuming so...
    2. Should I purchase the 3 snubberized PSU boards for this also?
    3. What transformers with dual secondaries (this means I can run 2 channels of one transformer right?) should I purchase... I'm assuming the ones for the smaller non-parallel will be smaller than for the parallel amplifier

    Help please?? purchasing these before the end of the night hopefully
     
    M

    mangrovejack

    Member
    2004-12-08 10:23 pm
    Brisbane
  • #3
    Can I ask why you only need 70 watts for your midranges, and 100(!) watts for your tweeters. Surely you don't need that much?

    In answer to your questions,

    1) Yes, if you want one amp with 4 channels and another amp with 2 paralleled channels, then you will need 8 LM4780 boards.
    2) Not sure how you'd wire up three PSU boards to 8 boards symmetrically though. I would have gone with 4 PSU's personally.
    3) a 500-700VA toroidal should be enough for each amplifier.
     
    M

    mangrovejack

    Member
    2004-12-08 10:23 pm
    Brisbane
  • #5
    Ah ok, I didn't know what type of speakers you were trying to drive.

    The PSU boards are the rectifier boards. There is no difference between the two. The PSU board contains the Diodes, and capacitors.

    For your 4 ohm loads, you'll want a lower voltage (for more current). I'm not entirely sure what the maximum would be (considering the chips are in parallel) but a safe voltage would be 18v secondaries (which will give roughly 25v after rectification).
     
    S

    sachi

    Member
    2003-12-18 9:43 pm
    Silicon Forest
  • #7
    Hello ther..
    sorry to butt in..i just received my PCBs for the 3886 and the 4780 from Peter..

    Now i am building a 3 way active monitor and am planning to use these two amps along with a Nad 320BEE..

    I would want to know ur suggestions regarding the transformers VA and secondary rating ...how many trannies will i need for the 3886 and the 4780..

    also which amp should power which driver..considering the load and power handling of the drivers ?

    The tweeter is
    http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=264-526
    midrange
    http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=299-492
    woofer
    http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-315

    please advise...
     
    A

    Audiophilenoob

    Member
    2005-05-07 6:10 am
    NC
    www.soundsolutionsaudio.com
  • #8
    mangrovejack said:
    Ah ok, I didn't know what type of speakers you were trying to drive.

    The PSU boards are the rectifier boards. There is no difference between the two. The PSU board contains the Diodes, and capacitors.

    For your 4 ohm loads, you'll want a lower voltage (for more current). I'm not entirely sure what the maximum would be (considering the chips are in parallel) but a safe voltage would be 18v secondaries (which will give roughly 25v after rectification).
    Click to expand...

    alright that's what I thought about the rectifier boards... the kits come with those and parts to populate the boards
     
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