Murder fund - WH16NS40 16x - Blu-Ray BDR / BDXL burner

wannaburnstuff said:

On the way up to max power though if we record the mW/mA on a graph we should see where efficiency drops off. As it will be the same chemistry inside the diode, we can probably infer a general idea of what current to not exceed. I believe we will always see some degradation simply due to them all being chemically similar.

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IIRC most 405nm diodes will keep on increasing in efficiency and power until they suddenly pop and die. They don't really have a drop off.

I'm fully aware that a longevity test could compromise the max power test. The point is what good is knowing max power of one diode if it cannot handle half the current for more that a few hours. Lots of people including myself have built not pushed all that hard 405's just to have them pop a few months later. I don't think we should be judging them like the 445's. 405 diode degrading is a pretty big issue, a lot of members money has been wasted and a lot more could if these diodes aren't looked at for what they are. But what do I know, I'm just a dude with a sonic-ish avatar

Like I said, we won't know that from a simple weekend of testing. Data like that, as crappy as it is, is found out from us members having diodes die. The diode isn't going to signal "hey, this is a safe current!". That's what the recommended current on the datasheet is for (that we don't have, or use).

To put it simply, we won't know what works until we lose a few. This is how diode testing works, it's a dirty science, but it's also an art form.

Can't make an omelette without breaking a few eggs.

EDIT: Yes, ARG, this is also true. It's a dangerous fact when testing these. You can get steady increase on almost all of the current 405's until it suddenly pops. That's how a couple have gotten 1W. It's just a steady increase until the diode has enough, and when you're getting that dangerous, it's VERY hit or miss. This diode will likely be dead by the end of testing.

TheDukeAnumber1 said:

The point is what good is knowing max power of one diode if it cannot handle half the current for more that a few hours.

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I just don't really think that's ever the case with a diode. I mean, I haven't known of a widespread issue with diodes dying after a few hours, at half their max power. If something like that happens, I would tend to look at it being a user error / build problem / random stroke of bad luck -> all things that a longevity test (or something similar) wouldn't address anyway.

I think this has largely been said already, but I'll state / reiterate my view of the purpose of this (and similar) threads. This thread does not presume that the diode found in this new drive will be worth building with. Rather, that's the question this thread seeks to answer.

It very well may be that this test reveals that the diode underperforms the 12x diodes we can currently source for $50. Or, the diode may outperform typical 12x diodes, but to such a small degree that it doesn't make building with them an attractive option given their price tag.

What everyone is hoping for, is a lead on a better diode, that warrants further investigation by the community. Think of this murder fund as the initial hurdle that needs to be cleared before the community puts any further resources into that investigation. There's no sense running complex longevity testing (if that's even something we'd do) before we know whether this diode is even a candidate to replace our use of 12x diodes.

Whatever the community wants then. I hope you weren't reiterating for me though I'm aware of the purpose of diode testing threads.

I agree with Bloom on this one. Would need multiple samples (at least 3) to determine the diode life vs drive current.

There is a YouTube video out there with a guy who built a "laser gun" with a x16 in a toy gun host. He claims in the video it does 1w and is more powerful than the x12. He doesn't back it up with any testing on an LPM on the video but it might be worth trying to contact him to see if this is the same x16 and if he did in fact LPM it. I will try to find the video again and see if I can get in touch with him. IIRC it is a fairly new video so it could be this new drive.

Jmillerdoc said:

There is a YouTube video out there with a guy who built a "laser gun" with a x16 in a toy gun host. He claims in the video it does 1w and is more powerful than the x12. He doesn't back it up with any testing on an LPM on the video but it might be worth trying to contact him to see if this is the same x16 and if he did in fact LPM it. I will try to find the video again and see if I can get in touch with him. IIRC it is a fairly new video so it could be this new drive.

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Hopefully it will at least be one of the two (this drive, or the one DTR is testing).

rhd said:

Hopefully it will at least be one of the two (this drive, or the one DTR is testing).

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Agreed. 1W of stable 405 would be amazing. I still have that Amazon Credit lying around, if one of these turns out to be golden, you can bet I'll be ordering it!

Lazeerer's 405nm diodes do 950mW with a G lens.

wannaburnstuff said:

Lazeerer's 405nm diodes do 950mW with a G lens.

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I actually had (still have, though I put it into a new build at a lower current) a diode from the (sf? Bw?) 512L that did 950mW with a G lens - and that's not even to "good" 12X diode in most peoples books.

If these new diodes hit around the 1W mark, with a G lens, at twice the price, I don't think it will be an earth shattering find.

Perhaps this could be used to calibrate your spectrometer.

Got a black light? File:Fluorescent Black-Light spectrum with peaks labelled.gif - Wikimedia Commons

Your spectrometer would have to be fairly sensitive.

You could also try tickling a mercury switch if you have one of those. They are in old thermostats.

bloompyle said:

Perhaps this could be used to calibrate your spectrometer.

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RHD, if you are not going to bid on this let me know so I can bid

I'm not neat idea, but I'm not going to recalibrate my spectro, and 4x DPSS wavelengths has served worked well for calibration in the past.

Thanks

I'll be bidding on it then. Thanks for the link Bloom!