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'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

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  • 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

    This is a pretty good combination as far as I'm concerned.





    Here is the link to the other thread about the amp; it's got some more info: http://techtalk.parts-express.com/sh...hlight=micro-s

    I want to change a few little things. Since the speakers are so close to the table, I'd like to have the terminal reversed aiming the wires down as they come out of the plugs, also, I'll have to reverse the orientation of the switch so 'on' is up. Maybe a smaller knob also.

    I had thought of putting a light or lighted switch on the front baffle, but the 'Quarks' are clean looking, and I didn't want to clutter up the lines, so I installed a 5mm super-bright blue LED on the bottom of the cabinet an inch or so behind the kitchen cabinet drawer pull 'outrigger' feet. The little blue dot on the placemat under the speaker is visible, but not overly-bright as many blue LED's can be. I like it a lot.

    I dremel'd out a recess for the top arc of the handle to sit in -- maybe 1/8" deep or a bit deeper. One screw and some epoxy to keep it stable. Not a bad look, it angles them up a bit which helps a bit. A little hard to see:



    Better look here:


    I actually forget the type of veneer I used, but it has a nice figure to it but it was unbacked, so therefore a bit more of a hassle to get it on the piece, even though they are small.



    I made the cabinets but they are the same size as PE's knock-down version Jeff used except I mitered the corners for veneer, and I made the baffle out of 3/4" thick and inset it 3/8' or so. Baffle is Rustoleum texture paint with black satin on top.

    I put the steel core inductor in the middle on the bottom of the cab, and then hot glued these three pieces together and hot glued that to the bottom near the rear. Fat fingers like mine need not apply. I glued the front baffle on after everything was installed, it helped, but it was still hard to get in there.



    Overall, the sound is pleasing... neutral, no bad sounds at all when driven within reason. A lot of smaller speakers bother me somewhere in the midrange with a 'ringey' type of sound on some vocals/horns/strings, these are good in that range. I listened to them for 1/2 hour right in front of them as I read a magazine over lunch, and from classical to jazz and popular they did fine with everything.

    Pretty amazing for the size really... I know the woofers are sold out, but it looks like they have been incorporated into a flat-pack package for all to consume over at diy soundgroup. I thought I'd post this in case anyone wants to construct a tidy built-in amp for a desktop or computer setup.

    TomZ
    Last edited by tomzarbo; 06-07-2015, 05:54 AM.
    *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

  • #2
    Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

    Tom, you come up with some of the best ideas I've seen here. I never would have thought of using cabinet handles as feet. Brilliant. And the down-firing LED is pretty cool, too.
    "We’ve heard that a million monkeys at a million keyboards could produce the complete works of Shakespeare; now, thanks to the Internet, we know that is not true."
    –Robert Wilensky

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    • #3
      Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

      Originally posted by Jonathan Anspach View Post
      Tom, you come up with some of the best ideas I've seen here. I never would have thought of using cabinet handles as feet. Brilliant. And the down-firing LED is pretty cool, too.
      Thanks a lot Jonathan,

      I really dig how the LED hits the table, not too bright, but you can still see it clearly. I was originally going to cut the handles in half and have the feet come out on an angle from the front corners, but this seemed a better idea, easier to get even too. Thanks sir.

      I should mention that I used Rustoleum Painter's touch 'ultra cover' on the back and bottom. It's laytex, but it's good thick stuff. I rolled it onto the back and bottom just once -- kind of thick, but it dosen't run easily. It's not flashy, but it does cover MDF end grain just fine and it's got a flat-ish flaw minimizing effect. I didn't even tape off the veneer (I poly the veneer first) I just rolled it on and wiped any excess off the poly with a damp paper towel. How's that for easy?

      TomZ
      *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
      *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

      *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

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      • #4
        Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

        Super Cool Tom! And like Jonathan said earlier, the cabinet handle was such a simple solution I never would have thought of it. Everything looks top notch. Cant wait for the next one you do.
        My "No-Name" CC Speaker
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        • #5
          Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

          That amp is so bad a$$. Looks like a perfect fit for the Quarks, which sounded pretty good at InDIYana.

          Dan
          _____________________________
          Tall Boys
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          • #6
            Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

            Everything about these is so clever and very well done! Really great work!

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            • #7
              Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

              Thanks for the kind words guys.
              Regarding the amp...

              http://www.parts-express.com/pam8610...board--320-604

              It doesn't mind 4 ohm loads where it claims 20 watts per channel of output... but is rated at just around 10 watts at 8 ohms. Since the 'Quarks' are more like 8 ohm speakers and obviously not super-efficient given their size, I think the amp runs out of steam just a bit before the speakers do.

              Still, given the nearfield nature of their intended use, this setup gets MUCH more than loud enough. I've been using a 12v, 5 amp switching power supply to power it. The amp doesn't get too nasty sounding even when maxed out. They're set up on my kitchen table for the time being... I've heard clear music all through the house on it when turned up 75%, and that's with a 7 yr. old iPod providing the signal; a computer output will do quite a bit more.

              I just can't believe how stinkin' tiny the amp board is. It's about the size of half of a credit card! The amp chip is just a bit bigger than 1/4" square. It's amazing what they can do these days. It's for sure a great time to be a DIY'er.

              The entire project is just a bit over $18 minus the cost of a 12v PS and LED's; Pretty cheap for what you get, including a clutter-free desk!

              I also think they would work very well with at pair of 'Overnight Sensations' and 'Neo Nano's' -- which is what I did my initial testing on. Bass was surprisingly nice on those. If the amp was cutting the bass like some T-amps do, I couldn't tell.



              Besides being a great speaker, the 'Quarks' were one of the smallest speakers available to show what this amp would work in. However, an even smaller box size would be possible by turning the terminal cup 90 degrees... hey, that gives me an idea!

              TomZ
              *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
              *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

              *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

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              • #8
                Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

                Great project, Tom! Really nice work.
                -Kerry

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                • #9
                  Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

                  Very clever outtigger Tom.
                  " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                  Quote Originally Posted by hongrn. Oct 2014
                  Do you realize that being an American is like winning the biggest jackpot ever??

                  http://www.midwestaudioclub.com/spot...owell-simpson/
                  http://s413.photobucket.com/albums/pp216/arlis/

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                  • #10
                    Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

                    Very cool. You executed it perfectly.

                    Can the amp be bridged and put one in each speaker?
                    - Ryan

                    CJD Ochocinco ND140/BC25SC06 MTM & TM
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                    CJD In-Khan-Neatos - A Dayton RS180/RS150/RS28 In/On Wall MTW

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                    • #11
                      Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

                      Originally posted by ---k--- View Post
                      Very cool. You executed it perfectly.

                      Can the amp be bridged and put one in each speaker?
                      Thanks guys.

                      I don't think it can be bridged, but I haven't tried to do that. It can power 4 ohm speakers all day long at loud volumes without the amp chip getting even warm with a 12v 5 amp PS. I don't know enough to guess if it would die or not trying to do that, I'm guessing it can't be reliably done, though.

                      TomZ
                      *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                      *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                      *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                      Comment


                      • #12
                        Re: 'Micro-S' 2-Channel amp in Jeff Bagby's 'Quarks'

                        kind wish PE carried these two amps i saw on sure electronics site, as they might be worth looking into. though they dont have onboard volume pot.
                        http://store.sure-electronics.com/au...00w/aa-ab32166
                        [email protected]@10%THD with 20v-in
                        [email protected]@1%THD with 20v-in

                        http://store.sure-electronics.com/au...ard/aa-ab32472
                        [email protected]@10%THD with 21v-in
                        [email protected]@1%THD with 21v-in

                        if you want more power into one speaker and each speaker has a one of those pam amps. why not mod it to where the either channel is feed into both inputs, so that either left or right is feed to both channels. then its just a single speaker that is bi-amped by a single pam amp, that would be doable where bridging it wont work. distortion over all should be down vs a single channel feeding both drivers, no?

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