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2 x 15W Class-D Stereo Power Amp Kit

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  • 2 x 15W Class-D Stereo Power Amp Kit

    I've been eyeballing this thing in the Parts Express catalog.



    2 x 15W Class-D Stereo Power Amp Kit



    And I'm trying to convince myself I need it just because it's so cheap and pretty but do I really? I was thinking I could use my Zoom G3X with amp modeling as a preamp, then to the power amp, then to some bookshelf speakers or maybe the 10" speaker in one of my amps. But I dunno. Is this a waste of time?



    Questions:

    1) What kind of enclosure could I use for this thing and am I drilling holes and stuff?

    2) Can I just use an old laptop computer power supply for it or should I buy theirs?

    3) Am I going to electrocute myself?

    4) Will it sound good?

    5) If I only have one speaker hooked up to it, will it fry itself?

    6) How do the outputs work on this thing? Do I have to install jacks on the board or something? What kind?



    I do like the sound of the Zoom through a set of computer speakers, but I'm thinking a setup with this card and some regular speakers could sound nice.



    This is what happens when I buy things and then get catalogs. BTW, the Eminence Red White and Blues speaker is awesome.
    Guitars:
    -Fender Wayne's World 2 Stratocaster w/Fat '50s pickups
    -Fender Blacktop Jaguar HH
    Amps:
    -Fender Champion 110 w/Lil' Buddy
    -Fender Princeton 112 Plus w/Red White and Blues
    -Crate Palomino V8
    Effects:
    -Way Huge Swollen Pickle Jumbo Fuzz
    -Pro Co You Dirty Rat Distortion
    -MXR Carbon Copy Delay

  • #2
    Ias eyeballing a small Lepali Tripath TA2020A there that comes with a power supply for $22.

    I'm in the same boat. What would I use it for.Might make a good computer monitor but its not like I havent

    got plenty of those.

    Comment


    • #3






      Quote Originally Posted by WRGKMC
      View Post

      Ias eyeballing a small Lepali Tripath TA2020A there that comes with a power supply for $22.

      I'm in the same boat. What would I use it for.Might make a good computer monitor but its not like I havent

      got plenty of those.




      That looks pretty sweet too. Is Class T or Class D better as a guitar power amp?
      Guitars:
      -Fender Wayne's World 2 Stratocaster w/Fat '50s pickups
      -Fender Blacktop Jaguar HH
      Amps:
      -Fender Champion 110 w/Lil' Buddy
      -Fender Princeton 112 Plus w/Red White and Blues
      -Crate Palomino V8
      Effects:
      -Way Huge Swollen Pickle Jumbo Fuzz
      -Pro Co You Dirty Rat Distortion
      -MXR Carbon Copy Delay

      Comment


      • #4
        Questions:

        1) What kind of enclosure could I use for this thing and am I drilling holes and stuff?


        Just do a search for "project box" from the same website you're buying the amp kit from. A plastic (ABS) box will be fine for this and is easier to drill as well. Class-D runs very cool, so no need to worry about venting the enclosure.

        2) Can I just use an old laptop computer power supply for it or should I buy theirs? Any power supply over 12 volts *should* work, but it won't put out it's rated power with only 12 volts. A 28 volt supply will yield more output power and less distortion.

        3) Am I going to electrocute myself? NO. But thank you for asking.

        4) Will it sound good? The speaker(s) connected to it will make the biggest difference. If the amp is built and powered correctly, should be less than 1% harmonic distortion, very low for a guitar amp.

        5) If I only have one speaker hooked up to it, will it fry itself? NO, it will be fine. Class-D doesn't care about open-circuit outputs.

        6) How do the outputs work on this thing? Do I have to install jacks on the board or something? What kind? Looks like there's big holes and solder pads on the PCB for those 2-way binding posts speaker terminals as well as smaller holes where speaker wires would be soldered on.
        This space left intentionally blank.

        Comment


        • #5






          Quote Originally Posted by Wayne2
          View Post

          That looks pretty sweet too. Is Class T or Class D better as a guitar power amp?




          Both are HiFi stuff and arent going to do very good as as a guitar amp. A guitar amp amplifies mostly midrange between 100 ~ 6Khz.

          One of these will give you full trebble and bass responce. Might be OK for an acoustic guitar but even then its a matter of the preamp

          being strong enough. Both will have line level inputs which means the guitar will need additional preamplification to boost the input up

          to instrument level which is hotter than line level. Then you will also need a tone stack that is good for guitar.



          You could use an external guitar preamp effects unit that will give you the proper tone and drive. I do this recording direct

          into a full frequency line input of my recording interface and monitor system which is basically the same thing. The guitar preamp has

          EQ's drive and effects that will make a HiFi system sound like a guitar amp. You could probibly do it with a couple of floor pedals too.

          A distortion/overdrive pedal and EQ pedal plugged into a HiFi type amp should allow you to dial up something that sounds like a guitar.

          Add a compressor for some tube like feel and sustain and you may be OK.



          Main thing is a 15W transistor anp isnt going to produce a whole lot of sound. As Mr Grumpy says the speakers will be important.

          If you use some really high SPL speakers over 95db it should make for a decent practice amp but its not going to have the drive

          a normal 15W guitar amp has. Figure it to be maybe 1/2 to 1/3 of a normal guitar amp at the most. The preamp stages in the thing

          just arent going to have the same drive to the power amp. The preamps are biased to stay clean, not to achieve maximum loudness.





          About the power supply, I think they recomend a switching power supply but you may have to double check.

          The big item is the size of the caps. Larger caps have a power/current reserve. Its like having larger batteries.

          If you were to start a truck with a small battery. The voltage may be OK, but the thing doesnt produce enough amps

          to turn the large coil in the heavy duty starter.



          Same kind of thing with an amps power supply. A wall wart with small caps arent going to have a current reserve and

          when the power amp is hit hard with a loud bass note or guitar chord, theres no reserve current to drive the speakers.

          Comment


          • #6
            Cool stuff but I don't think it will work good for a power amp for a guitar.

            Comment


            • #7
              Thanks guys. I tried to reply earlier but HC was being fussy. I think I'm still confused about the output posts though. If I mount them directly to the card, how do they stick out the side of the box? Do I need the exact right size project box? Or should I run wires from the card to posts that are mounted to the box? What about the input RCA jacks for that matter?



              I was thinking of using the Zoom G3X as the preamp. It has amp sims with speaker cabinet emulation.
              Guitars:
              -Fender Wayne's World 2 Stratocaster w/Fat '50s pickups
              -Fender Blacktop Jaguar HH
              Amps:
              -Fender Champion 110 w/Lil' Buddy
              -Fender Princeton 112 Plus w/Red White and Blues
              -Crate Palomino V8
              Effects:
              -Way Huge Swollen Pickle Jumbo Fuzz
              -Pro Co You Dirty Rat Distortion
              -MXR Carbon Copy Delay

              Comment


              • #8
                I think 15 watts would be plenty for most applications. Few guitar amps are more than 100 watts, and 15 watts through a 4x12 cabinet would be about as loud as 100 watts through a single 12". That's usually too loud for bedroom, practice or a small club. That's one reason a lot of low power guitar amps are available these days. If you need more, mic the speaker.



                Yes, another reason low power amps are used is so that they can be cranked, and this amp would not be suitable for that use. But it would still be plenty loud, through a guitar speaker.



                As for inputs and outputs, I agree that binding posts could be installed on the board, but access to them could well be dicey if the board is installed in a box. Same with the inputs. But there also appear to be holes into which wires can be soldered. Power supply needs to be 28 volts at 1 amp, I think, for full output.
                "The Web puts all of the world's knowledge at our fingertips; unfortunately it's mixed with all of the world's bull****************."
                -- Bob Parks

                "A thing is not necessarily true because a man dies for it."
                -- Oscar Wilde

                "No man dies for what he knows to be true. Men die for what they want to be true, for what some terror in their hearts tells them is not true."
                -- Oscar Wilde

                "It is a trap of history to believe that eyewitnesses remember accurately what they have lived through."
                -- Theodore White

                Comment


                • #9
                  I think 15 watts would be plenty for most applications. Few guitar amps are more than 100 watts, and 15 watts through a 4x12 cabinet would be about as loud as 100 watts through a single 12". That's usually too loud for bedroom, practice or a small club. That's one reason a lot of low power guitar amps are available these days. If you need more, mic the speaker.



                  Yes, another reason low power amps are used is so that they can be cranked, and this amp would not be suitable for that use. But it would still be plenty loud, through a guitar speaker.



                  As for inputs and outputs, I agree that binding posts could be installed on the board, but access to them could well be dicey if the board is installed in a box. Same with the inputs. But there also appear to be holes into which wires can be soldered. Power supply needs to be 28 volts at 1 amp, I think, for full output.
                  "The Web puts all of the world's knowledge at our fingertips; unfortunately it's mixed with all of the world's bull****************."
                  -- Bob Parks

                  "A thing is not necessarily true because a man dies for it."
                  -- Oscar Wilde

                  "No man dies for what he knows to be true. Men die for what they want to be true, for what some terror in their hearts tells them is not true."
                  -- Oscar Wilde

                  "It is a trap of history to believe that eyewitnesses remember accurately what they have lived through."
                  -- Theodore White

                  Comment

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