"Open Alpha" DIY project from MrSpeakers

Discussion in 'Headphones' started by Pyruvate, Nov 18, 2016.

  1. Pyruvate

    Pyruvate Friend

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    For the DIYers out there, Dan just opensourced a modified version of his Alpha Dogs. Love them or hate them, here's your chance to build your own pair using a Fostex T20/40/50rp while tuning them to your liking.

    [​IMG]
    [​IMG]

    http://www.head-fi.org/t/825868/open-alpha-t50-3d-printed-headphone-project-from-mrspeakers/0_40

    Dan has confirmed that the baffle and pad ring can be used to modify a Mad Dog into a Pro. Anyone have access to a 3D printer who wouldn't mind printing some parts for a fair price? If not, Dan also provided links to a site that can print the pieces for you for a nominal fee.
     
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    Last edited: Nov 18, 2016
  2. Philimon

    Philimon Friend

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    [​IMG] [​IMG]
    Open Alphas
     
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  3. purr1n

    purr1n Burned out

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    Is there a link to a site that can print the baffle? The HF link is broke and I hate perusing through HF.

    I like Mad Dog Pros.
     
  4. Vtory

    Vtory Audiophile™

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  5. purr1n

    purr1n Burned out

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    Thanks. I still have an old Drop T50RP collab and OG T50RP that can be successfully modded. I wish Fostex would revert their formula since the new ones seem unfixable (to sound neutralish).
     
  6. Philimon

    Philimon Friend

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    @E_Schaaf tweaked a mk3 version to neutralish here.
    @Hands did pretty nicely on a mk3 version as well here.
    @DEATHxMACHINE found getting neutralish on any T50RP variant to be difficult here.
    @purr1n youre just as close as anybody here but mk2.

    edit: More mk3 mods to neutralish here from @spoony , @JK47 , and @Biodegraded.
    Sorry if I missed some, Ill add to list whenever I find them.
     
    Last edited: Nov 18, 2022
  7. Philimon

    Philimon Friend

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    I can send you a set but modding to neutralish is outside my scope.

    For others, if youd like to outsource to a service then Shapeways is already setup in the Open Alpha thread op. Its pricey (like $150 but the quality is perfect.
     
  8. randytsuch

    randytsuch Facebook Friend

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    See if this head fi link works better
    open alpha head fi
    Thinking about dusting off my old pair of t50rp's and giving this a go.
     
  9. Philimon

    Philimon Friend

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    The original version shared by Dan Clark has been edited and improved by the community in several ways.

    First edit was to allow use of 2.5/3.5mm female connectors instead of expensive hirose. The second improvement reinforced the screw posts so they wouldnt break when tightening screws. Examples:
    https://www.thingiverse.com/thing:4250218
    https://www.thingiverse.com/thing:4743583

    The third upgrade was to add insert screws to prevent stripping screw post threads if youre one to open the cups a lot for retuning. Example:
    https://www.head-fi.org/threads/ope...-from-mrspeakers.825868/page-55#post-16655342

    There are a bunch more variants in the HF thread including open back versions.
     
  10. Philimon

    Philimon Friend

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    Another option is to just print the cups as the screw posts align with the stock T50RP baffle as seen below. Its an interesting choice with mk3’s because of the venting on the front-side of the baffle (exiting underneath the pads). Whereas the Open Alpha baffles are designed to work like a mk2 baffle which instead has small ports that exit to the rear cup for pressure relief. Pros and cons I presume… Ill try both types then update thread.

    (fyi: insert screw versions are not compatible)

    [​IMG]
     
  11. Philimon

    Philimon Friend

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    Caution!

    @zach915m is very soon to release a woody T50RP kit. Id wait and see what ZMF is offering if youre considering plunking down big money for Shapeways or your own 3DPrinter. There are cheaper services than Shapeways but Ive not researched so cant just recommend.

    Edit: It takes about $5 worth of PETG filament to print a complete Open Alpha. Shapeways uses ABS filament which is more complex to print and looks nicer.
     
    Last edited: Nov 11, 2022
  12. zach915m

    zach915m MOT: ZMF Headphones

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    Yes yes I already shot a build video. Just gathering pieces right now, trying to have it out around cyber Monday or at least before Xmas.
     
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  13. Philimon

    Philimon Friend

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    The driver baffle in all the files Ive seen have the baffle oriented with flat part up. The reverse side is full of little details and overhang which will require printing with supports for a successful print. Unfortunately in these tight spaces supports can be difficult to remove. A newb like me didnt realize you could reorient the object in any way for printing convenience.

    Here is my first print which was frustratingly time consuming and difficult to remove supports (i quit halfway through removing supports to look up an easier way). Latter prints were all done flipped so the flat part of the baffle was facing down which does not require supports so no finishing was needed.

    [​IMG]

    [​IMG]

    [​IMG]
     
  14. Philimon

    Philimon Friend

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    Comparison to flipped driver baffle which required no supports or extra finishing.
    [​IMG]
     
  15. Philimon

    Philimon Friend

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    [​IMG]

    All three parts stacked (top is pad mount ring). Next is driver and headband install then wiring. Driver and headband are easy and a total of 4screws per side. Luckily the stock T50RP screws can be reused for all this depending on your print quality otherwise may require some extra polishing by hand to get every thing nice and neat for fitment. Wiring requires soldering but half it is done already because you can choose to just reuse the stock wiring that’s already attached to the drivers. You just need to connect those to your new female connectors.

    [​IMG]
    [​IMG]
    ^This photo is from when I used stock T50RP baffles with OA cups. Photo is to show the stock wiring.
     
    Last edited: Nov 12, 2022
  16. Philimon

    Philimon Friend

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    ^ update RE: wiring

    I dont recommend using the stock cables because the strands are so thin its actually kind of difficult to work with for a newb solderer (like me). I switched to 22awg wire and it was so much easier. 22awg overkill but thats all I had around (see attached). And you probably want to use a length slightly longer than I used here so as to reduce strain on connection points when opening and closing cups.

    [​IMG]
     
  17. Philimon

    Philimon Friend

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    Ive not seen this mentioned before (but Im no expert) but the quality control on T50RP (mk3) is an issue. The drivers sometimes have excess glue absorbed into the driver rear damping filter. The glue makes the paper completely impermeable which I imagine causes major variance in sonics among units. Here are pics of two T50RP, the yellow stain is glue.:
    [​IMG]
    [​IMG]
    This is partly why I completely removed the stock damping paper filter… Im sure @zach915m has a solution.

    edit: A place for ideas on substituting driver paper filter is in the MKIII thread and T60RP thread.
     
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    Last edited: Nov 17, 2022
  18. zach915m

    zach915m MOT: ZMF Headphones

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    I think Titan Mesh might work? I'll try to run an experiment when I do the sonic portion of our DIY kit.
     
  19. Tachikoma

    Tachikoma Almost "Made"

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    Stretchy athletic tape (like this https://www.amazon.com/Powerflex-Stretch-Athletic-Tape-Rolls/dp/B003JIOKBU) worked for me. Rotate it diagonal to leave a couple holes in the corners if you need moar bass. Can also cover up the whole driver and just poke a hole in the tape for something in between.
     
  20. zerodeefex

    zerodeefex SBAF's Imelda Marcos

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    those might actually be my favorite headphone from Dan.
     

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