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"Micro-S" Terminal Cup Stereo Amplifier

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  • "Micro-S" Terminal Cup Stereo Amplifier

    I've been tinkering around with this for a week or so, finally finished buttoning it up. It's a 2-channel amp board built into one of PE's terminal cup's.



    It's running a set of Neo Nano's that I never got around to finishing.



    The center plug in the middle is the power input jack. The switch is on the left side, and the 3.5mm stereo input is on the right side. The potentiometer mounted on the amp board just mounts to the middle of the terminal cup and basically supports the board. It's like 1.5" square and weighs next to nothing.
    The pic below shows things a bit clearer.






    Wiring is pretty straightforward, I have big hands, so it took some fiddling to get things just so.



    I super-glued a zip-tie to the back of the cup to tie the inside speaker connection to for some extra strength. That lead would connect to the crossover in the speaker that this amp would be installed in. The banana plug terminals on the amp/cup would be run to and connect to the other speaker (the slave speaker if you will)

    The idea is that this little amp/terminal cup would be mounted in the back of a single Overnight Sensation, Neo Nano, or something similar allowing for zero desktop space being taken up for a computer desk. I ran the amp/neo nano combo as loud as I could tolerate for 20 minutes or so yesterday while I showered/shaved, and when I got back the chip on the amp was only 2 degrees warmer than everything else. It's about 1/4" square and doesn't seem to have a problem with 4 ohm loads and being played loudly.

    The source was an iPod classic with the EQ set to "bass booster" and the volume on the headphone output at about 90 percent of max volume. The bass boost made this combo sound very full and pleasing with the jazz music I prefer. With bass-type test tones, the bass boost did some weird modulating, could have been the iPod or the amp, don't know, but it sounded strange. Music only though, and it was pretty nice sounding.

    This combo sounds pretty nice and really has a sound comparable to the T-amp that PE sells, (the black one with the arched top) It distorts when cranked up very high, but it never really gets too ugly. I've been powering it with a 12V, 5 amp switching power brick. I didn't hear any hum or other bad noises while I was testing it.

    I did roast the first switch I tried soldering to... it melted like butter. I'd get a few extra if anyone decides to duplicate this project. Use a fine point tip on the wand and move quickly.

    I plan on fitting a piece of tubing to the shaft of the pot with a wooden dowel/knob on the end of it to adjust the volume. I didn't bother with a LED, since this will probably live it's life on the rear of a small speaker system.

    As far as sealing this against air leakage, I'm guessing your caulk of choice would be fine. I tried to pick bits that were pretty much air-tight looking, but that's not to say that any of them may not leak. I'd just put some caulk on a toothpick and seal up the mounting points and probably be done with it as long as nothing whistles. The terminal cup itself has a gasket pre-attached.



    As the pic above shows I had to grind some material away from the back of the cup to get the clearance to thread on the mounting nuts. I used a dremel type tool with a sanding drum for this. Also, the pot on the board has a little retaining pin which I needed to make a small notch for in the cup.



    Nothing too exciting I know but it was a fun project, and I think it would do the job of powering a set of computer speakers while taking up basically no room or interior volume whatsoever.

    Now I need to build a speaker set to put this thing into.

    TomZ
    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *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

  • #2
    Re: "Micro-S" Terminal Cup Stereo Amplifier

    That's pretty cool, Tom.
    Click here for Jeff Bagby's Loudspeaker Design Software

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    • #3
      Re: "Micro-S" Terminal Cup Stereo Amplifier

      Very cool Tom. Might be a nice project to try for some Xmas gifts.
      Paul

      The "SB's" build page
      http://techtalk.parts-express.com/sh...-4-(pic-heavy)

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      • #4
        Re: "Micro-S" Terminal Cup Stereo Amplifier

        What about the sub out?
        Otherwise- looks pretty cool,
        Wolf
        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

        *InDIYana event website*

        Photobucket pages:
        https://app.photobucket.com/u/wolf_teeth_speaker

        My blog/writeups/thoughts here at PE:
        http://techtalk.parts-express.com/blog.php?u=4102

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        • #5
          Re: "Micro-S" Terminal Cup Stereo Amplifier

          That's sweet! Gonna bring it to InDIYana?
          _____________________________
          Tall Boys
          NRNP Computer Sub
          The Boxers
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          Conneccentric
          UX3

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          • #6
            Re: "Micro-S" Terminal Cup Stereo Amplifier

            Very nice Tom. I like what you did and how you did it!
            Don't worry, if your parachute fails, you have the rest of your life to fix it.

            If we all did the things we are capable of doing, we would literally ASTOUND ourselves - Thomas A. Edison

            Some people collect stamps, Imelda Marcos collected shoes. I collect speakers.:D

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            • #7
              Re: "Micro-S" Terminal Cup Stereo Amplifier

              Very inventive and darn nice.
              Kenny

              http://www.diy-ny.com/
              DIY NY/NJ 2014 https://www.youtube.com/watch?v=FGwA...ature=youtu.be
              Man does not live by measurements alone, a little music helps.

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              • #8
                Re: "Micro-S" Terminal Cup Stereo Amplifier

                Tom you knucklehead! That's an absolute stroke of genius. I'm really impressed. WOW. All the best, Mike

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                • #9
                  Re: "Micro-S" Terminal Cup Stereo Amplifier

                  Very cool
                  --
                  "Based on my library and laboratory research, I have concluded, as have others, that the best measures of speaker quality are frequency response and dispersion pattern. I have not found any credible research showing that most of the differences we hear among loudspeakers cannot be explained by examining these two variables." -Alvin Foster, 22 BAS Speaker 2 (May, 1999)

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                  • #10
                    Re: "Micro-S" Terminal Cup Stereo Amplifier

                    Originally posted by Wolf View Post
                    What about the sub out?
                    Otherwise- looks pretty cool,
                    Wolf
                    I'm still waiting for that amplifier to get here. This one: http://www.parts-express.com/21-hi-f...8-vdc--320-608

                    I am really looking forward to getting those amps in. Kevin K sent me some really nice plastic panels pre-machined to mess with. I've got some ABS sheets from PE and even a 4" square anodized alum. plate to try out on that project as well.

                    I'm playing around with these in the meantime. Sharpening my soldering skills you know. Actually, just handling these tiny wires is kind of a pain with my bloated Shrek-type fingers. The thin wire used to wire this stuff up has more 'jacket' than wire and doesn't remember the shape you bend it into very well. I was soldering with one hand and holding the wire in a tiny pliers with the other. Soak up a small blob of solder and 'Pffffftttssszzzzz' get out before the thing melts. Maybe I had my temp to high on the iron, I'll have to double check that now that I think about it. Crossovers are much easier.

                    Originally posted by DanP View Post
                    That's sweet! Gonna bring it to InDIYana?
                    Contractually, I'm restricted to one DIY event per year for the 2015 DIY season. I'm hoping that my pending free-agency will enable me to attend more events in the future.

                    Truthfully, my spouse is fine with me attending MWAF and I may be allowed to escape for Roman's Brooklyn event next year since it's so close, but that's about all I can get away with at this point, I gotta keep the wifey happy, you know! I do build a lot of projects over the course of a year, but most of them are 'Zarboified' versions of others projects, borrowing from the excellent designs of so many others...

                    For about $25 you can have a decent hidden amp including terminal cups for both speakers. Not too shabby price-wise. Oh, plus the price of a 12V power supply if you don't already have one laying around.

                    Thinking about it some more, I may wire in leads for a LED that could be mounted on the front of the powered speaker, just for some bling as well as a reminder that the thing is actually on.

                    Thanks for the kind words...
                    TomZ
                    Last edited by tomzarbo; 04-12-2015, 09:55 AM.
                    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *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

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                    • #11
                      Re: "Micro-S" Terminal Cup Stereo Amplifier

                      Really quite neato!
                      Paul

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                      • #12
                        Re: "Micro-S" Terminal Cup Stereo Amplifier

                        Good job, Tom!

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                        • #13
                          Re: "Micro-S" Terminal Cup Stereo Amplifier

                          Great project and writeup Tom

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                          • #14
                            Re: "Micro-S" Terminal Cup Stereo Amplifier

                            Nice project, tight little thing. All my questions were answered by reading your writeup.

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                            • #15
                              Re: "Micro-S" Terminal Cup Stereo Amplifier

                              Originally posted by tomzarbo View Post
                              Contractually, I'm restricted to one DIY event per year for the 2015 DIY season. I'm hoping that my pending free-agency will enable me to attend more events in the future.
                              You never fail to make me laugh out loud when I read your stuff!:D I hope she understands what "free-agency" means.;) Nice job on this little project, really cool.
                              My "No-Name" CC Speaker
                              Kerry's "Silverbacks"
                              Ben's Synchaeta's for Mom
                              The Archers
                              Rick's "db" Desktop CBT Arrays
                              The Gandalf's

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