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  • #46
    I am about to order parts to attempt the Isetta as my first speaker build.* I have a couple questions that I'm hoping Paul or someone else can help me with.**

    1) The design says the following regarding the port tube:**
    "The port is 1.5" in diameter, and 10.5" long.* The port is mounted on the side of the enclosure, because that's pretty much the only place it would fit.* I recommend a flared port if you can get/make one to alleviate chuffing under high SPL."

    Does anyone have a recommended source for the port tube?* The closest I can find is PE Part # 260-402, which is a 1-1/2" x 4" flared.* I initially thought about gluing 2 end to end, but that's still only 8".* I looked on other sites and found nothing else in 1.5".

    2) The SketchUp diagram on Paul's site shows no bracing.* Yet, when I look at the picture of the finished design on his site, the screws holding the face of cabinet on do not line up with anything.* What am I missing here?* Is there bracing not shown?**
    Speaker Cabinet Port Tube 1-1/2" ID x 4" L Flared

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    • #47
      I had the same problem.

      Go to Home Depot or Lowes and buy a piece of 1.5" PVC pipe. It's cheap, even if you have to buy 10' of the stuff. Use a hole saw that matches the outside dimension of the pipe. Cut to length and glue it flush to the outside. You can flare the end with a round over bit in a router after the box is assembled. Locate the hole carefully, because there is not a lot of extra space when you are mounting an amp board inside.

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      • #48
        Originally posted by scary View Post
        I had the same problem.

        Go to Home Depot or Lowes and buy a piece of 1.5" PVC pipe. It's cheap, even if you have to buy 10' of the stuff. Use a hole saw that matches the outside dimension of the pipe. Cut to length and glue it flush to the outside. You can flare the end with a round over bit in a router after the box is assembled. Locate the hole carefully, because there is not a lot of extra space when you are mounting an amp board inside.
        +1.

        A 1 7/8" hole saw (and a tiny, tiny bit of sanding) will allow a tight press fit of the 1.5" PVC pipe into the enclosure, no glue needed. Testing on scrap is advised lest you split the panel.

        Note that nominal 1.5" PVC pipe has an actual inside diameter of 1.61" - a 7% increase in diameter or a 15% increase in port area over a true 1.5" port. The port length may need to increase accordingly (but elbows are easy with PVC pipe). Also, if white PVC is not to your color scheme, the electrical section has nominal 1.5" PVC conduit in grey.


        The pic below shows a 1.5" white PVC pipe press fit into 3/4" melamine faced MDF. To facilitate the press-in, chamfer the outside edge of the PVC pipe. Press it thru the panel so that the chamfer extends past the panel's outside surface then sand smooth or use a round-over bit in a router. A very small round-over will only remove material from the PVC pipe. A larger round-over will remove some of the surrounding panel exposing the MDF. In the pic below, that was the case and the exposed MDF was painted with white nail polish to match the overall color scheme.

        Click image for larger version  Name:	PVC Port.jpg Views:	1 Size:	10.5 KB ID:	1376000

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        • #49
          Thanks for the pointers on the port!* Sounds like an easy enough solution.**

          Any thoughts on the bracing?* The SketchUp plan shows no bracing, yet the finished photo shows screws that would seem go into nothing (or be 3" long), or go into unshown bracing.
          *

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          • #50
            You have a choice between a removable baffle, a removable back panel, or if you use an external amp, you could just glue the whole thing together. If you go with the removable baffle, you will have to put some triangle shaped gussets in the corners.
            Whichever you choose, make sure to get a good seal.
            I went with a removable back, because I could mount the amp board, knobs and power socket together on one accessible panel.

            What amp are you using?

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            • #51
              I was eyeing the*Lepai LP-168HA.* I like the USB port on the back as I intend to add a Chromecast Audio.* That way I only have a single power cord.**

              I'm not sure how I want to mount it.* I'll probably just screw it on to the back of the cabinet.*

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              • #52
                I have tried the LP168 HA with the Tang Band W5 woofer and it did not work at all well. The amp only puts out about 8 watts on the "sub" channel. Check out some of the U tube videos which actually test it.

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                • #53
                  Originally posted by Drjay View Post
                  I have tried the LP168 HA with the Tang Band W5 woofer and it did not work at all well. The amp only puts out about 8 watts on the "sub" channel. Check out some of the U tube videos which actually test it.
                  Have you found a replacement?

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                  • #54
                    This one works really well.* Nobsound TPA 3116D2 2.1 *

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                    • #55
                      You will likely need a DC to DC isolation module regulator (~$11 from digikey plus shipping) to avoid current loops between the amp and the Chromecast.

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                      • #56
                        Which one?

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                        • #57
                          The one described as having: "2017 latest version, Treble&Bass independent control, add the subwoofer frequency adjustment, add the pre-amplification; Redesign the low pass filter, the subwoofer is more powerful; The right VOLUME knob turn to end is Shutdown"* *The sub frequency control* works pretty well although I've not determined actual its range. At the huge online retailer it sells for around $56 without a power supply and $73 with a 19 V PS. Not the cheapest but by far the best I've found for its type.

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                          • #58
                            Thanks, I know the unit you describe.

                            For IWanaGoFishing, that amp is available as a module without the case for less than half the price.* No need to spend the money on the case if your going to embed the amp inside the box.*

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                            • #59
                              Thanks! I've been reading up on the one linked below. There is good feedback on YouTube and Amazon.* I like the adjustable crossover for the .1 and the ability to turn the cross over on and off for the full range speakers

                              I also like the fact that it does not have Bluetooth built in, as that seems the be the source of some of the noise that people complain about.

                              If I add a step down converter to 5v for a USB to power a Chromecast, do you think I am likely to run into ground loop or other noise?
                              Your Audio Solutions HQ Since 1986. Shop 18,000+ Audio Parts from Speakers and Subwoofers to Home Theater and Pro Audio. Top Gear at Low Prices and FREE Shipping.
                              Last edited by IWanaGoFishing; 05-18-2018, 05:11 PM. Reason: Removed link to competitor.

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                              • #60
                                You probably should nuke the link to a sale item that competes with PE's in stock merch.
                                Later,
                                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*

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

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