Pioneer 12X Blu-Ray-- BDR-205

I just went back through the thread to see who it was that mentioned the vibration dampening system. It was LuxIgnis. I have a complete 203 and a 205 drive now (minus the diodes), but I don't think you want to pay to have these shipped to Italy just to look at the differences between the drives.

If you do, cool. If you don't, cool. If no one wants to examine the differences between the two drives, Imma harvest the bits and bobs for FlaminPyro and toss the carcasses in the trash.

Peace,
dave

Some food for thought, in the form of an image. This is from a paper published by Samsung all the way back in 2006, but still valid. These diodes have one difference in structure, but look at the performance: Same threshold, roughly the same slope efficiency (~200mW @ 200mA), they look very similar. But with that one smart engineering move by Samsung, the top one CODs at roughly HALF the output power of the second.

I'm not saying that my theory earlier is correct, in fact that may be something the diode makers were doing already. But the point I was trying to make is the point being made by this chart by Samsung 3 years ago: if your diode is dying via COD, then you can use some smart engineering to improve COD-resistance without doing anything else to the performance of the diode.

Is that what is happening here? I don't know. We certainly can't say the diodes are different, they look very similar. Can we say for certain the diodes are the same? I would say no, there could easily be differences not apparent. Definitely very similar, but I wouldn't say for certain that they're the same.

Personally, I think the two 12x diodes look very different from the 8x diodes in the 2nd plot FrancoRob posted in post #232, "8x/12x Comparison - Efficiency %". I'm certainly no expert, but I find it hard to overlook the significant difference in shape of those curves. Anyone have any thoughts on what could give the 12x diodes that curve on the efficiency plot with a peak and kind of a wave form?

maxh said:

Personally, I think the two 12x diodes look very different from the 8x diodes in the 2nd plot FrancoRob posted in post #232, "8x/12x Comparison - Efficiency %". I'm certainly no expert, but I find it hard to overlook the significant difference in shape of those curves. Anyone have any thoughts on what could give the 12x diodes that curve on the efficiency plot with a peak and kind of a wave form?

Click to expand...

That's an artifact from Excel trying to guess at what is happening between the known points. Look at the raw data, Dave measured every 50mA. Excel looked at the points every 50mA, and tried to draw a polynomial between those points, and to be quite honest, didn't do a very good job in that case. Replotting it with a different chart type gives a different shape.

Every curvature in that chart is Excel artifact assuming what it thinks is happening in the gaps in the data. But I can pretty much guarantee that the efficiency isn't making a sine wave as current increases. Look at just the data points, the data points that Dave gave every 50mA, and you'll see the patterns are mostly the same. Excel just decided to draw the interpolation differently for those 2 plots. Especially that first peak, that first peak isn't real. The peak happens at like 110 or 115mA, but Dave measured at 100 and 150mA. That peak is a bad guess on the part of Excel, and isn't real.

You have to be careful extrapolating data in all of science, and not just extrapolating past known points. Interpolating between known points can be just as dangerous, and you can never completely assume you know what is happening between known points. In this case, Excel missed, and drew a bad interpolation to get its polynomial to fit.

pullbangdead said:

Some food for thought, in the form of an image. This is from a paper published by Samsung all the way back in 2006, but still valid. These diodes have one difference in structure, but look at the performance: Same threshold, roughly the same slope efficiency (~200mW @ 200mA), they look very similar. But with that one smart engineering move by Samsung, the top one CODs at roughly HALF the output power of the second.

I'm not saying that my theory earlier is correct, in fact that may be something the diode makers were doing already. But the point I was trying to make is the point being made by this chart by Samsung 3 years ago: if your diode is dying via COD, then you can use some smart engineering to improve COD-resistance without doing anything else to the performance of the diode.

Is that what is happening here? I don't know. We certainly can't say the diodes are different, they look very similar. Can we say for certain the diodes are the same? I would say no, there could easily be differences not apparent. Definitely very similar, but I wouldn't say for certain that they're the same.

Click to expand...

Exactly what I was thinking. So now our only hope is that pushing these higher doesn't kill them like it does to 8x, even though they have similar slopes (before the 8x death)

pullbangdead:

IMHO, I think that each single correction note, when performed under scientific purpose, must be witnessed with the examples and/or hypotized improvements; it is not sufficient to say "this interpolation is wrong" but it is important to show what kind of interpolation is right.

BTW, this is the good opportunity to decide, between all Forum members, what kind of plot method will have to be used from now in the future: a stright point to point, or an armonized point to point?

Just to show the difference, herewith is the Eff. % plot performed with the stright point to point method:




So, I hope to read soon about the choice of the "official" method to use, if the Forum members still believe that Excel plots may be useful for the research scopes, as your last sentence looks to put doubts on it.

pullbangdead said:

That's an artifact from Excel trying to guess at what is happening between the known points.

Click to expand...

Well that was my last bastion of "hope" that we could "know" that these were different diodes. That leaves us with good news and bad news.

The bad news, these are very likely the same diode that is in the 8X. Also, we are still left with PBD's earlier question about "tougher" mirrors. The only way to test this would be to kill one

The good news is that everyone else can purchase the 8X drives and get the same diode for less money. Also, the release of the 12X drive MAY drive the cost of the 8X down a bit.

Since I was just informed that we are not going to offer Winter Session classes (8 weeks off without pay) I will treat these as 8X's. Can't afford to kill one for science.

Peace,
dave

I haven't heard from anyone about wanting to see these complete drives. I'm going to harvest the bits and bobs then and discard the rest.

Peace,
dave

daguin said:

Since I was just informed that we are not going to offer Winter Session classes (8 weeks off without pay) I will treat these as 8X's. Can't afford to kill one for science.

Peace,
dave

Click to expand...

Are you a teacher Dave?

Crazy Jay said:

Are you a teacher Dave?

Click to expand...

I am a professor of human communication (public speaking, argumentation, debate, rhetoric, interpersonal comm, intercultural comm, oral interp, etc) here in Southern California. When the economy tanks, so does the budget at state colleges and universities.

Peace,
dave

daguin said:

I am a professor of human communication (public speaking, argumentation, debate, rhetoric, interpersonal comm, intercultural comm, oral interp, etc) here in Southern California. When the economy tanks, so does the budget at state colleges and universities.

Peace,
dave

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It shows in your posts. You know how to choose your words.

Have you ever thought about running your own little internet laser shop?

Crazy Jay said:

It shows in your posts. You know how to choose your words.

Have you ever thought about running your own little internet laser shop?

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That would turn my hobby into a job. Then I would have to get another hobby

Peace,
dave

Hmmm...


So Daguin is a professer in humain communications...

That explains his post count...

Either way I think that the faster writting speed was acheived thru better optics and control programs...

But to get a real answer, we would need to push a diode quite far and do a stress test, then compare the results (lifetime, efficiency and power degradation) with a 8X using the same kind of test. That would be quite time consuming and expensive...


The other way would be to conveince (I'm not sure about the spelling...) the manufacturer to give us the datasheet... Not that easy either!

BuildAbluraylaser said:

Hmmm...


So Daguin is a professer in SPAM...

That explains his post count...

Click to expand...

:crackup:
:crackup:
:crackup:

daguin said:

That would turn my hobby into a job. Then I would have to get another hobby

Peace,
dave

Click to expand...

Could you give me some advice on where to start looking/reading to learn more about what you teach? I don't have subjects like that on engineering.