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Another Carmody "Speedster"

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  • johnchabin
    replied
    Sorry so late in my reply... here's my BOM:

    Soniccraft
    2 x Gen I Sonicap 2.2 uF 200VDC (506416)
    4 x Gen I Sonicap 4.7 uF 200VDC (506572)
    2 x 10 Ohm Mills MRA-10 (630252)
    2 x 8 Ohm Mills MRA-12 (634230)

    Parts Express
    2 x Jantzen Audio 0.25mH 20 AWG Air Core Inductor Crossover Coil (255-026)
    2 x Jantzen Audio 1.5mH 18 AWG Air Core Inductor Crossover Coil (255-260)
    2 x Tang Band W4-1720 4" Underhung Midbass Driver (264-872)
    2 x Fountek NeoCD1.0 Ribbon Tweeter (296-701)
    2 x Dayton Audio BPA-38NI HD Binding Post Pair Nickel (091-1246)
    2 x Parts Express Speaker Cabinet Port Tube 1-3/8" ID Adjustable (260-388)

    Meniscus Audio
    2 x 0.35mH, Layer Wound 18ga. (LW8.35)

    Box was made from scrap pieces from other projects.
    Last edited by johnchabin; 01-08-2020, 01:25 PM.

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  • mrdrew
    replied
    I really appreciate your guys' input. I made my final orders, and project will be coming together before the end of November 2019, this month. Here's the build post. I'm gonna @ you folks

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  • Jeff F.
    replied
    Original baffle width is recommended but Paul does always say that + or - 10% is OK.

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  • a4eaudio
    replied
    Ideally, you should keep the width the same as the original 6.0" as the crossover is designed for that width and adjust the height and depth as needed to keep the internal volume the same. (I say "ideally" because there is a good chance that the difference won't be audible at your actual listening position.)

    Some options:
    W H D in3 ft3 L % of Original
    Original 6" 10" 8.5" 337.5 0.195 5.53
    A 6 10.25 10 334.7 0.194 5.48 99.2%
    B 6 10.5 9.75 334.1 0.193 5.48 99.0%
    C 6 10.75 9.5 333.0 0.193 5.46 98.7%

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  • mrdrew
    replied
    Got shopping list updated with the four caps. Going over the drawing, Carmody specifies 5.5L internal volume. I'm building this from 3/4in MDF, so increased the dimensions a half inch to accomodate for that thickness. But the back.
    Internal volume 5x9x7.5 = 337.5 cu in, = 5.53L. so that's correct. But, this also means the backside is completely recessed into the box, instead of 8in tall inside height, it's only 7.5in to come out with that correct internal volume. Am I splitting hairs here? Or is this important? With a flush mounted back, I'd come out with:
    5x9x8 = 5.9L
    Click image for larger version

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  • Jeff F.
    replied
    Originally posted by mrdrew View Post
    Jeff F.

    You'd mentioned 4 4.7uf caps, but the BOM only calls for two, and I'm pretty sure it's the parts for the pair.
    The BOM lists the 4.7uf caps twice, 2 both times. Look at the XO schematic, you will need 4 to build the pair.
    Click image for larger version

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  • Chris Roemer
    replied
    I'd certainly go w/the Dayton (either should be fine).
    The added DCR might drop the woofer output by -0.05 to -0.10 dB. Not audible, and probably not even measurable.

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  • mrdrew
    replied
    Jeff F. Alright, made those two updates to the Dayton Audio resistors. Then, regarding the inductor, Carmody specifies .35mH inductor 18-19AWG, I can't use one of those 0.35mH 20 AWG inductors? Jantzen #255-030, or Dayton Audio #257-030? I'm sure I can find the specific inductor elsewhere, and just get all the other bits from Part Express.

    this inductor:
    https://www.madisoundspeakerstore.co...core-inductor/

    You'd mentioned 4 4.7uf caps, but the BOM only calls for two, and I'm pretty sure it's the parts for the pair.

    (also, I'm getting the tweeters elsewhere, so I left them off)

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  • Jeff F.
    replied
    Originally posted by mrdrew View Post
    Thanks Jeff F.! Yup, I was going off that one. But there are still various selections I can make, or have to compromise on if the exact ones don't exist. I'm not smart enough to know what numbers are super important!

    There are some other fiddly bits on there, but I'm most interested the correct crossover parts.

    Please and thank you!
    Looks like PE doesn't stock an 18ga .35mH coil. Don't forget to get 4 of those 4.7uf caps. Also, I'd get these https://www.parts-express.com/dayton...sistor--004-10 and these https://www.parts-express.com/dayton...esistor--004-8 you really on need the 10 watt resistors.

    Leave a comment:


  • mrdrew
    replied
    Thanks Jeff F.! Yup, I was going off that one. But there are still various selections I can make, or have to compromise on if the exact ones don't exist. I'm not smart enough to know what numbers are super important!

    There are some other fiddly bits on there, but I'm most interested the correct crossover parts.

    Please and thank you!
    Attached Files

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  • freddrich
    replied
    excellent work

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  • Jeff F.
    replied
    Originally posted by mrdrew View Post
    johnchabin do you have your build list of materials? I want to make sure I get the right stuff from parts-express.
    From Paul's site
    Click image for larger version

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  • mrdrew
    replied
    johnchabin do you have your build list of materials? I want to make sure I get the right stuff from parts-express.

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  • AdamM3
    replied
    Nice job! Aluminum baffle looks cool

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  • johnchabin
    replied
    Thanks Paul!

    I used silicone adhesive. They're very solid.

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