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  • Toni Table Radio - Build Thread...

    I've been trying to get good sound in the hands of my friends and co-workers now for several years. Getting to know the folks you work with, and what they may or may not want in their house audio-wise without spoiling the surprise is sometimes challenging, but kind of fun. I've gifted a few sets of speakers and 2.1 systems recently to co-workers and my wife is happy that our house is beginning to look less like a speaker store and more like her long-missed family and living room. I've been wanting to build something for a friend from work who has been an encouragement to my wife and I to start walking, running, and basically getting into better shape. My spy... um.... I mean spouse visited their home a while back and upon my stealthy suggestion, discovered that their house was really set up just nice and cozy and Eileen didn't think that a traditional set of speakers would be best. I suggested a table radio and she thought that would be the best solution. Not everyone wants a big set of speakers hogging up their living room and I understand that.

    Anyway, I've been wanting to do a nice table radio for awhile now and this is my chance to do a small, but nice sounding radio with mid 60 Hz bass and high-quality finish work. It's a variation on my "Sound Traveler" project from last year that nobody knows about Here's that thread: http://techtalk.parts-express.com/fo...e-sound-system
    It's a shame that nobody ever built that, because it's stinking awesome for what it is. Well, this will do that one better because although it will use the same amp, the table radio will utilize PE's new pre-amp board that has MP3 input, bluetooth, SD, and USB inputs, as well as FM and a remote control. I'm planning on using some nice waterfall bubinga on the case and even removable grills so you can see the little ND-65's pumping away. Vented this should be able to hit 65 Hz, just like the Sound Traveler project, but this radio will also include a 3.5mm volume controlled line-out jack for future subwoofer addition if the need or desire arises.

    Here's where I'm at so far...

    Click image for larger version

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    Not too hard to plug away at once the top and bottom panels are cut.

    Not visible is a tapered riser plate on the bottom which will be 3/4" to 1" tall at the back and around 1.5" tall at the front to angle the sound upwards. Also, that bottom portion will be used for additional cabinet volume as I need all I can get!

    More...
    Attached Files
    *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
    I think I came up with a cool little helping tip on using MDF as a template...
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    Once I got the curves on the sides and all the angles on the 3/4" MDF template as perfect as I could... I saturated the end grain with wood glue twice to harden up the material. I've noticed in the past that the trim router bearing can tend to dent the MDF end grain over multiple passes. It looks like my trick worked because I see no denting at all after running four panels on it with multiple passes on each.
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    Nothing too exciting, but it should go together quickly. The curve is fairly aggressive on the sides and I'll use a few 1/4" thick braces to keep things sturdy during the application of the side panels. I'll be using two layers of 1/8" HDF to make each side. I'll pre-bend it a bit to make the process easier; it doesn't take a whole lot to get this stuff to take a bend so that shouldn't be a problem.

    Luckily, the output connector for the preamp/faceplate connects directly into the input jack on the 50 wpc amp so I don't have to hack the board to get it connected. Of course, I'll be splicing that line to take a subwoofer line output to the rear of the radio to run to a subwoofer in the future if they/we want... I'm making one for us as well, mostly as a prototype to 'get things right' with before applying what I learn to the one I intend to give to my co-worker. I'll include a bit of venting to insure the amp doesn't get too hot.

    Not much to see yet, but hopefully you can see where I'm going with this... I'm hoping it comes out looking really fantastic for my friend at work. I'll even give spray Lacquer a try on the Bubinga on this one. I want the finish super-shiny and perfect as I can get it. No rub-on poly this time.

    Oh, the dimensions are approx. 15" wide, 9" deep and 5-6" tall at the front, more or less. Vent should be a 1" by 5-6 inches depending on how the box size ends up.

    More to come....

    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


    • #3
      Deft spray lacquer is great stuff. I use it on everything. Onlyb$6 at the Depot. I prefer the satin finish as if you build it up it is almost semi gloss all thatvpolynand rub on stuff is too labor intensive for me.
      "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

      The Madeleine
      The Roxster
      Swopes 5.0
      Acoustic Panels
      Living Room Make Over

      Comment


      • #4
        Very nice! I'm definitely interested in your build progress. Thanks for sharing.
        If life were fair, Elvis would still be alive today and all the impersonators would be dead.
        ~ Johnny Carson

        Bungelow Ed's Photo Album http://techtalk.parts-express.com/album.php?u=8594

        Comment


        • #5
          Here's where I'm at right now...

          I've been pondering how to exactly mount the amp and voltage reducer thingy and I think I've settled on this.
          The amp screws to the thin board with standoffs and the voltage reducer just screws in with some #4 screws with a small slice of tubing to hold it off the little piece of 1/2" thick MDF.

          The slot opening down the middle of the radio is exactly 1.5" wide so I cut the amp mounting board a smidge less than that and I'm planning on putting a piece of gasket mounting tape on the end of the two small pieces of 1/2" MDF and just slide it "friction-fit" style into the opening. I think this will work okay. I won't have any room for anything else in that little slot except the on/off button on the top of the radio, but that's fine. I can put the filter... probably a LR coil and resistor similar to the one in the 'Sound Traveler' setup in the bottom hidden by the base.

          I'm plugging along but as usual, work is getting in the way of my hobby.

          Bases are up next. I'm trying to decide if I will curve them the same as the sides or just use an angle similar to the curve. Decisions.

          TomZ
          Attached Files
          *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


          • #6
            Just a follow up question on this amp/buck converter setup... do you think there is anything dangerous going on here? I plan on drilling several holes in the bottom of the enclosure under where the amp will live... as well as a vent on the back near the top so air can flow through if there happens to be any appreciable heat building up. I think the amp will run very cool though in this arrangement. It will be well under it's full output capabilities and will be driving two small speakers. I don't imagine the converter will get warm either since it will also be well under-taxed.

            I think I'd be comfortable with this for myself, especially since there will be a main switch on top that turns the whole thing off, but I always wonder with wood and electronics. Just me being paranoid I guess. Plus, the intended giftee is a former electrician.

            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


            • #7
              Tom,

              I can't see which amp your using there. But both the TI TPA311x series and ST Micro TDA7492 chips spec self thermal shut down at 150 C (302 F). That's measured on the chip and I doubt the heat sink will ever get that hot before shutdown. I've also read a mfg's spec that rates it's MDF "auto ignition" temperature at 200 C to 275 C.

              I might try to lose the rear MDF "brace" near the buck converter to improve air flow.

              Looks an awful lot like a "Blose" table radio (sorry for that).

              Comment


              • #8
                Originally posted by tomzarbo View Post
                Just a follow up question on this amp/buck converter setup... do you think there is anything dangerous going on here?
                TomZ
                ​Probably not...depends on how much current that Bluetooth radio draws. The problem with those linear regulators is that they are very inefficient for large voltage drops. If you put in 24V and have it output 12V, and the current draw is 300ma, the regulator will generate 4W of heat ((24-12)*.3). That's actually a lot of heat for a confined space. If the current draw is only 100ma, the heat generated is 1.2W, which is probably fine. I usually go with switching regulators when the input-output differential is greater than 5V or so, because they are much more efficient and you don't have to worry about heat dissipation.

                ​If you have any problems with heat build-up, I can send you one of the switching modules. I bought 3 of them off eBay but didn't realize each order included 5 modules. I've got extras...
                Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

                Comment


                • #9
                  Originally posted by Millstonemike View Post
                  Tom,

                  I can't see which amp your using there. But both the TI TPA311x series and ST Micro TDA7492 chips spec self thermal shut down at 150 C (302 F). That's measured on the chip and I doubt the heat sink will ever get that hot before shutdown. I've also read a mfg's spec that rates it's MDF "auto ignition" temperature at 200 C to 275 C.

                  I might try to lose the rear MDF "brace" near the buck converter to improve air flow.

                  Looks an awful lot like a "Blose" table radio (sorry for that).
                  Thanks a lot Mike for the input.

                  That MDF brace is only about 1.5" deep, there is an inch or so on the top and bottom for air to flow around... looks deceiving in the picture. Those MDF braces are actually what will secure the amp board assembly in the cavity, so I kind of need them.



                  It does look a bit like the Bose radio... it looks an AWFUL lot like my parent's Cambridge sound works table radio as well. I didn't realize how much until I saw it a few days ago again. I wanted curves and the sides are really the best place to put them I guess. It will look a bit different once it gets "lifted" on it's base... But I agree, and I don't mind the comparison. If their wave radio didn't cost as much as a mortgage payment it would be pretty cool IMO.

                  It's this amp BTW: https://www.parts-express.com/tda749...2x50w--320-606 The TDA7492 amp. I've used it in my Sound Traveler project and it does stay pretty cool.

                  Thanks again for the look-over. I always feel better when someone who knows what they're doing looks at what I'm doing.

                  TomZ
                  Attached Files
                  *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


                  • #10
                    Originally posted by neildavis View Post

                    ​Probably not...depends on how much current that Bluetooth radio draws. The problem with those linear regulators is that they are very inefficient for large voltage drops. If you put in 24V and have it output 12V, and the current draw is 300ma, the regulator will generate 4W of heat ((24-12)*.3). That's actually a lot of heat for a confined space. If the current draw is only 100ma, the heat generated is 1.2W, which is probably fine. I usually go with switching regulators when the input-output differential is greater than 5V or so, because they are much more efficient and you don't have to worry about heat dissipation.

                    ​If you have any problems with heat build-up, I can send you one of the switching modules. I bought 3 of them off eBay but didn't realize each order included 5 modules. I've got extras...
                    Neil,
                    I'm using a 16v power supply brick and the faceplate preamp needs 12v. The specs don't say how much amperage the faceplate draws, I just sort of assumed it was going to be pretty minimal. I should probably wire it up before I finish this thing up and see if it gets hot enough to be an issue.

                    As an alternate solution, I could always just run the whole thing off of 12v. I think the amp would still have enough oomph to run these little full rangers. Then I wouldn't need to worry about bring the voltage down. I was trying for a few more clean watts with the 16v as opposed to 12v, but I guess the difference would be minimal.

                    Thank you for your suggestions, Neil.
                    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


                    • #11
                      You shouldn't have a problem with just a 4V drop (16v - 12v). I'm guessing the radio module is 200ma or less when the Bluetooth is being used. That means there will be less than 1W dissipated in the regulator. A 24V input could pose a problem, but 16V should be fine.
                      Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

                      Comment


                      • #12
                        Originally posted by neildavis View Post
                        You shouldn't have a problem with just a 4V drop (16v - 12v). I'm guessing the radio module is 200ma or less when the Bluetooth is being used. That means there will be less than 1W dissipated in the regulator. A 24V input could pose a problem, but 16V should be fine.
                        Thanks for the insight Neil. I'm probably going to give it a try both ways and see what the temps are when I get farther along.
                        If 12V provides enough distortion-free volume, I may just stick with that anyway.
                        I sometimes end up making things more complicated than they need to be... Just ask my wife.

                        And thanks for the offer in post #8, Sorry, I didn't see that the first time reading through. It's good to have extras!
                        That little voltage reducer thing was $.56 cents I think, I ended up buying 6 of them to have some extras, and at that price, who knows if they will all work.

                        Free shipping from China... $3.36 total. I don't know how they do it... it would cost more than that for me to ship 6 of them to the house next door. Marlin P Jones has them for $2.95/ea, not including shipping. Of course I'd buy from PE first if they had something similar.

                        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


                        • #13
                          I've been plugging way at this very little by very little... but I'm having a ton of fun. As it turns out, I enjoy working on a project for 40 minutes at a time!
                          Pic of basic box with components hanging on and lifted up a little to approximate the base.

                          This top-down view is the base assembly more or less....
                          Attached Files
                          *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


                          • #14
                            Here is the base gluing up and the little front amp air hole "C" piece gluing up...

                            The upside down "U" shape is an airspace which will vent air from the front middle section of the base up through the radio cabinet, through to the back where there will be another vent.
                            The two 1/4" pieces of MDF on the sides (lighter pieces) will be sanded and routered to the same radius as the bottom 1/4" plate.
                            Then I plan on fastening the base assembly to a board with two slanted boards on either side, on which I will slide a "C" Channel of wood with a router flush trim bit attached to machine the angle on the base.

                            Tough to explain, but hopefully this weekend I will have that part finished up (if the router arrives in time)

                            TomZ
                            Attached Files
                            *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


                            • #15
                              This has inspired me. I may make something similar. Only hurdle is calculating the internal volume.
                              "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

                              The Madeleine
                              The Roxster
                              Swopes 5.0
                              Acoustic Panels
                              Living Room Make Over

                              Comment

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