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Thread: Ebay 8, 10, 15, 30 watt RGB Modules Any Good

  1. #1
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    Question Ebay 8, 10, 15, 30 watt RGB Modules Any Good

    Anyone have experience with these ebay RGB high power modules, such as TechHood sells?

    I saw an old thread posted when they started to appear talking about the drivers being PWM inetead of true analog (aka "analogue" for you Europeans &#128521.

    Anyone have experience or know about the beam quality, alignment, ability to maintain the alignment, and whether I can replace the driver with a higher quality one.

    I do notice they appear more concerned with pumping the wattage as high as possible than providing a good color balance, but some of them seem to balance the individual laser powers better than others.

    Oh, and I am curious how they are getting these powers at that price point. I am assuming knife edging.

    Any info or thoughts would be appreciated!

  2. #2
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    A few people had problems with them years ago. Others have had no complaints.

    Recently they seem to be selling a lot of higher-power modules at very cheap prices, although the poor beam quality suggests that they are not using any sort of secondary correction for the fast axis in those higher-power modules.

    A friend recently purchased a pair of 20 watt RGB modules from them and was pleased with the results, but he was using them for a beam-rail application so he didn't mind the divergence and didn't even test the modulation response.

    I'd say if you are OK with the beam specs, it's hard to beat their pricing. If they were really a terrible seller, I think their feedback would reflect it.

    As to how they are able to sell the modules so cheaply, I can only assume the answer is "Because, China."

    Adam

  3. #3
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    Quote Originally Posted by buffo View Post
    A few people had problems with them years ago. Others have had no complaints.

    Recently they seem to be selling a lot of higher-power modules at very cheap prices, although the poor beam quality suggests that they are not using any sort of secondary correction for the fast axis in those higher-power modules.

    A friend recently purchased a pair of 20 watt RGB modules from them and was pleased with the results, but he was using them for a beam-rail application so he didn't mind the divergence and didn't even test the modulation response.

    I'd say if you are OK with the beam specs, it's hard to beat their pricing. If they were really a terrible seller, I think their feedback would reflect it.

    As to how they are able to sell the modules so cheaply, I can only assume the answer is "Because, China."

    Adam

    Well I pulled the trigger on one... Went conservative at 10 watts to see what i get.

    Supposedly they are fiber coupled and produce a less than 2mrad divergence.

    I'm also wonderif if I can add my own optics and clean up the beams a bit.

    I'll post my experience... Probably 3-4 weeks before it arrives.

    Thanks for sharing your thoughts. I was briefly worried you might say they had the divergence of a flashlight and were aligned with toothpicks propping up sliced up vanity mirrors! 🤪

  4. #4
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    Quote Originally Posted by MountainGoat View Post
    Well I pulled the trigger on one... Went conservative at 10 watts to see what i get.
    Cool! Please share your results when it arrives.

    I'll admit that I've been tempted to pick up a pair of the 15 watt modules they sell. After hearing about my buddy's project to resurrect his beam rails, I realized that I have most of the parts needed to make a pair of rails myself - if I had the laser modules, that is.

    Supposedly they are fiber coupled and produce a less than 2mrad divergence.
    I think you meant to say fiber-corrected, yes?

    Some of the listings show a divergence of "<3mrad", while others show "<1-2mrad", which seems intentionally vague. Although for a beam rail application, even 3mrad would still be acceptable.

    But if they *are* using fiber-corrected diodes, then a divergence of ~ 1.5 mrad is about right.

    I'm also wondering if if I can add my own optics and clean up the beams a bit.
    Depends on how much work you're willing to put into the project... Based on the module size, I suspect there won't be enough room inside to add any more optics. However, if you're willing to expand the baseplate and re-mount some of the optics, then the sky is the limit when it comes to secondary correction. You could even add a Keplerian collimator with a spatial filter at the focal point to really clean things up. Sure, you might end up losing 10-15% of your output power, but if you're starting with 10 watts, that's not a big deal. Alas, most people (myself included) don't have the patience for such a detailed re-working.

    I was briefly worried you might say they had the divergence of a flashlight and were aligned with toothpicks propping up sliced up vanity mirrors! 🤪
    HAHA! I've seen some janky optical mounts over the years, that's for sure. (Hot glue on bent strips of flexible sheet steel to hold a dichro, or fiber packing tape wrapped around an angle bracket to hold a bounce mirror...)

    But these days it seems that just about all manufacturers (not just the Chinese) are using the same tiny brass mounts that use a single screw to hold the mount to the baseplate (pivoting on this screw's axis gives you "X" axis adjustment) and another single screw to hold the mirror carrier block (or other optical element carrier block) in place against the mount (pivoting on this screw's axis gives you "Y" axis adjustment). I can only assume that they tweak things by hand until the alignment is correct, and then while holding the mount in place with some sort of jig, they tighten the screws just until they seat. When all of the mounts has been thusly aligned, they cover each screw with some UV cure epoxy and bake the whole module under a UV lamp to lock everything in place.

    I've had to crack the lid and re-align the knife-edge mirrors on a handful of these modern, multi-diode modules from China, and I have to say that I am *NOT* a fan of these single-screw mounts. Trying to hold the damned mount in place while you tighten the screws is frustrating as hell. Inevitably the mount will shift a tiny bit when the screw seats. You can either try to predict how much it will shift and offset the alignment by that much, or you can try to force the alignment back to neutral once you've seated the screw. Either method requires multiple attempts to get the alignment perfect.

    I'd much rather work with a flex-mount that has separate adjustment and locking screws, or even better, a typical kinematic mount like an MM1. But I also recognize that these single screw mounts are very affordable, and they can be packed together very closely to reduce the size of the module. I also begrudgingly admit that once these single-screw style mounts are properly aligned and glued in place, they almost never move. So I understand why they are used, even if I hate working on them. (Fortunately, at least most manufacturers are still using MM1s for the dichros, so tweaking the color alignment is still relatively painless.)

    When your module arrives, would you be willing to crack the lid and post some pictures of the optical layout of the module? I think that might spur some interesting discussion.

    Adam

  5. #5
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    Quote Originally Posted by MountainGoat View Post
    Well I pulled the trigger on one... Went conservative at 10 watts to see what i get.

    Supposedly they are fiber coupled and produce a less than 2mrad divergence.

    I'm also wonderif if I can add my own optics and clean up the beams a bit.

    I'll post my experience... Probably 3-4 weeks before it arrives.

    Thanks for sharing your thoughts. I was briefly worried you might say they had the divergence of a flashlight and were aligned with toothpicks propping up sliced up vanity mirrors! 🤪
    how much did it cost? Fiber coupled lasers are usually very expensive.

  6. #6
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    Quote Originally Posted by kecked View Post
    how much did it cost? Fiber coupled lasers are usually very expensive.
    Pretty sure he meant "Fiber-Corrected".

    TechHood is selling 10 watt RGB modules for less than $650 on E-bay. So, yeah, doubtful that they are fiber-coupled.

    Honestly, at that price, even fiber-correction is a bit of a stretch, although I'll concede that when China is involved, there seems to be so such thing as "a price too low".

    Adam

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    Quote Originally Posted by buffo View Post
    Pretty sure he meant "Fiber-Corrected".

    TechHood is selling 10 watt RGB modules for less than $650 on E-bay. So, yeah, doubtful that they are fiber-coupled.

    Honestly, at that price, even fiber-correction is a bit of a stretch, although I'll concede that when China is involved, there seems to be so such thing as "a price too low".

    Adam
    We shall see. I intend to open it up and look inside. Will share pics

  8. #8
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    Quote Originally Posted by buffo View Post
    Pretty sure he meant "Fiber-Corrected".

    TechHood is selling 10 watt RGB modules for less than $650 on E-bay. So, yeah, doubtful that they are fiber-coupled.

    Honestly, at that price, even fiber-correction is a bit of a stretch, although I'll concede that when China is involved, there seems to be so such thing as "a price too low".

    Adam

    Iím sure I was wrong about fiber coupled. My bad. ☺️

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