Pioneer 12X Blu-Ray-- BDR-205

[IgorT]

..the high forwardvoltage could be a problem soon.. once we find out they are good for obscene outputs, and the (current?) flexdrive is not able to put out that high current at those voltages..

Luckily the apparent high forward voltage came from an error in my measuring setup.
As i have shown with the first two 12x's, their Vf's are LOWER than with 8x's at the same currents, NOT higher!



The reason it came to this error is the way i tested the diode. I only have two wires coming out of my Diode Analyzer... The device then measures the current THROUGH them and the voltage ACROSS them.

But it measures the voltage inside the device.

And since it measures at the end of wires where current flows through, and all wires have a certain small resistance, a small but noticable voltage dropp is introduced, directly proportionate to the current flowing through.


I could have avoided this problem by using four wires going to the diode connector. Two for the current and two separate ones, through which no current would flow, to measure the voltage across the diode directly (the closer the better)..

But since i didn't want a mess of wires (avoiding it was one of the reason i built the Diode Analyzer), i only used two, and then "measured" their resistance by shorting the diode connector end, passing current through the wires, reading off the measured voltage drop, and using Ohm's law to calculate their resistance.

A simple formula then removes this additional voltage drop from the measured voltage, and i am left with the diode Vf alone....



However in this case i made a mistake and introduced additional resistance into the setup. And my usual calculation only accounts for the known resistance of the two wires coming out of the Diode Analyzer, so i didn't notice the mistake until after i was done testing and compared the numbers to others...


Just a few minutes ago i also plotted the Vf into the plot i used to show the 12x's are different from 8x's, and it was WAY off (as well as climbed too fast)!


It was definitelly a measurement error, and i will have to repeat the test.
I am sure that after i re-plot it properly, it will come out low in comparison to 8x's, just like the first two...


These diodes are made to operate at a certain voltage, and higher power diodes are supposed to operate at the "same" voltage, even tho they need more current.

This means that at the same current, the Vf of higher power diodes HAS to be lower than that of lower power diodes (on average)...

Until now it was a rule, that higher power diodes had higher Ith's. But the 12x's displayed the exact opposite.. This really confused me, when i was trying to figure out if they are new diodes, until i realized the above about the Vf.


When it comes to Vf's, i am pretty sure, that other than variations due to standard manufacturing tolerances, the Vf's of these diodes will stay around 5.5V even tho we will drive each higher power diode with a higher current.

 

[jayrob]

Not to thread jack too much, but I guess you have been too busy to check your e-mail and PM's huh Igor?

I have had your items ready to ship for several days, and am just waiting for the invoice that you said you wanted to make for the package. (customs)

 

[IgorT]

Not to thread jack too much, but I guess you have been too busy to check your e-mail and PM's huh Igor?

I have had your items ready to ship for several days, and am just waiting for the invoice that you said you wanted to make for the package. (customs)

Oh man, i forgot i didn't send it yet. :yabbem:

I had a crazy week at work yes, today is the first day i have some free time. I'll send you the invoice now.


EDIT: Sent. Thank you for your work, Jay!

 

[Meatball]

Just to point out... I have a BDR-205 running at 305ma. I'm using the flexdrive, and it seems to be lasing just fine! The flexdrive is still kicking, so I don't think mine is above 6V..

 

[More Power]

Hopefully they can be run much higher than that.

 

[jayrob]

Just to point out... I have a BDR-205 running at 305ma. I'm using the flexdrive, and it seems to be lasing just fine! The flexdrive is still kicking, so I don't think mine is above 6V..

I just built my BDR-205 12X with a FlexDrive at 320mA's...

It is very stable at 465mW's using 2 X AA batteries. No problem with the FlexDrive in this build...

12X Blu-Ray Star Trek Phaser video! - Click here!

 

[More Power]

I ordered the 12x but its not in yet. Slow boat from China I guess

 

[Hemlock_Mike]

Is there a difference between the BDR-205 BK and the BKS version?
My sled looks like Dave's but has the number B 3500041693 A on it.

HMike

 

[mmykle]

That better be a 12x I can't wait until 20x diodes come out. It's only a matter of time. However, I wonder what will be done in terms of heat sinking. I would laugh if companies put FANS in the bluray drives.

 

[Traveller]

I would laugh if companies put FANS in the bluray drives.

I wouldn't be all that surprised because one of my first CD writers (~'99) had a fan at the rear of the 3.5" format case... !

 

[mmykle]

I wouldn't be all that surprised because one of my first CD writers (~'99) had a fan at the rear of the 3.5" format case... !

Seriously? That would suck. Could be worse I guess though... they could be liquid cooled.

 

[IgorT]

Just to point out... I have a BDR-205 running at 305ma. I'm using the flexdrive, and it seems to be lasing just fine! The flexdrive is still kicking, so I don't think mine is above 6V..

At 305mA it's unlikelly the Vf would come close to 6V, but the two 12x's i tested so far have both shown much higher Vf's than 8x's.


I initially used Dave's Vf info to "proove" that 12x's are new, different, higher power diodes than 8x's.

Unfortunatelly after re-testing Dave's diode, i couldn't match his data, and i double checked everything (initially i put the high Vf down to an error in my setup introducing a voltage drop).



Here is a comparison of Dave's original measurement and mine in a double PIV plot:

The Data Comparison plot shows that both of us measured pretty much the same PI values, except for some minor bends in the original data, while i measured much higher Vf values overall.


I can't explain how it came to this discrepancy, but i'm fairly certain my data is correct, as i checked the Diode Analyzer readings with two DMMs. Usually the DMMs don't disagree more than 0.05mV, and the Diode Analyzer is calibrated to show the same as my better DMM. At the same time Dave's DMM should not be showing much different values than any of mine, so this is a small mystery to me.



In any case i believe it is known by now that the 12x's show higher Vf's than 8x's in general. They also form their own Vf group distinctly different than 8x's, similar to what i shown before, only higher than 8x's instead of lower.



Personally i only tested two 12x's so far, but the other one had an even higher Vf, as can be seen in the second attachment.

This diode is from a Plextor 12x drive i mentioned before, but we know it's the same as Pioneer, due to the identical sled...


At 400mA the Vf would come to approx 6.3V (extrapolated - the diode was only plotted to 360mA).



Still i believe this Plextor diode to be the exception rather than the rule. With 8x's, the Vf's varied a lot as well, and some diodes stood out from the crowd, either having much higher or much lower Vf's, similiar (but unrelated to) their slope efficiency variations)..
Incidentally, this Plextor 12x is also a freak in efficiency, reaching almost 620mW at 400mA, but as i said this is unrelated to the unusually high Vf.


Most 12x's should come closer to just under 6V at 400mA, but this is one thing that would be safer to check first.

 

[Crazy Jay]

I could get around 550mws with 400mahs? I think I'll get one of those and sell my 8x in a side button host.


Edit: I will be getting internet very soon... Can't wait to be back!

 

[IgorT]

I could get around 550mws with 400mahs? I think I'll get one of those and sell my 8x in a side button host.


Edit: I will be getting internet very soon... Can't wait to be back!

You would most likelly get more than 550mW at 400mA from an average 12x. The diode in the first attachment is a lower efficiency 12x, the one Dave sent for the murder experinment, but it unexpectedly became undead for reasons unknown. :cryyy: