Bought 20 pcs LD1014D from AliExpress, and got 2 pcs from wg45 (Mr, Pass' stash).
Using the Ld1014D, build a simply LuFet power amp and a audio IC/buffer based frond end voltage amp.
New LTSpice model added, post #22;
New Lufet amp added with PCB, post #30;
New headphone voltage front amp added, including PCB, post #33;
Base board with daughter board configuration added, post #41;
Few bugs in schematics and PCB board. Will be updated after testing.
Build started, post #54
Frequency response and THD+N measurement of the voltage stage, #57
Using the Ld1014D, build a simply LuFet power amp and a audio IC/buffer based frond end voltage amp.
New LTSpice model added, post #22;
New Lufet amp added with PCB, post #30;
New headphone voltage front amp added, including PCB, post #33;
Base board with daughter board configuration added, post #41;
Few bugs in schematics and PCB board. Will be updated after testing.
Build started, post #54
Frequency response and THD+N measurement of the voltage stage, #57
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again from Ali, bought a DC-DC boost converter, any notebook power supply as input, output 0.5V to 30V, the max current 4A, can be set at any value. The good thing of the converter is its voltage adjustment, spin wheel, one click 1 mV. And it has its own voltage and current output display, calibrated with a Fluke DDM, it is very accurate. Using a battery as -Vgs. The schematics see the photo.
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conclusion
the Vds, Id, Vgs and load have to be selected very carefully to have minimal distortion and triode character.
And I haven't found any LTSpice model close to real world in the forum.
the Vds, Id, Vgs and load have to be selected very carefully to have minimal distortion and triode character.
And I haven't found any LTSpice model close to real world in the forum.
Good information, thanks for taking the time to measure and publish the results.
Is the apparent negative output impedance (drain conductance) due to some thermal effect? If you can reduce the duration of the test current, how short a pulse can you measure with that meter, (auto hold fn)? What happens if you took the data in the opposite sequence of Vds steps?
Is the apparent negative output impedance (drain conductance) due to some thermal effect? If you can reduce the duration of the test current, how short a pulse can you measure with that meter, (auto hold fn)? What happens if you took the data in the opposite sequence of Vds steps?
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measured under DC. If Vgs varied from high to low, Id measured from high to low and low to high in both ways. each point given few seconds to let Id stabilized. If Vgs varied from low to high, Vds started always from 0.5V so Id from low to high.
You're about a month ahead of me. I've ordered shiploads of these parts from Ebay, and also ordered the pcb's direct from China. I have a feeling that my nieces, nephews and siblings are all going to be quite surprised when they receive a hand made amplifier in the mail, although I don't think it will happen this Xmas due to slow shipping.
Did you try shorting the pins on the "dead" units and re-testing them? Five out of twenty is significantly more DOA parts than usual, most people report 2%.
Did you try shorting the pins on the "dead" units and re-testing them? Five out of twenty is significantly more DOA parts than usual, most people report 2%.
Just checked my batch of 50, purchased from the likely same source. I’ve found 2 with disconnected gate, so nonfunctional.
If these were parts packaged by Lovoltech, I doubt there would be such high number of duds, if any. It is likely they are from some untested or discarded stock, purchased after Lovoltech factory closure and just packed by some wholesaler. There are even different cases with different marking (one in my batch).
It is not encouraging that you found only one perfect matched pair from 20.
If these were parts packaged by Lovoltech, I doubt there would be such high number of duds, if any. It is likely they are from some untested or discarded stock, purchased after Lovoltech factory closure and just packed by some wholesaler. There are even different cases with different marking (one in my batch).
It is not encouraging that you found only one perfect matched pair from 20.
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Just follow the procedure from your Hitchhiker’s guide: Money back -> repeat the order. 😀
Considering all, I wouldn’t order less than 100 next time.
Considering all, I wouldn’t order less than 100 next time.
Luckily that I now have Papa's gift for my F3 build 
Nice work wwwtttwww.
I bought 100 from aliexpress, and can confirm two different packages were included.
Had no issue selecting four for f1j, and its been sounding great, did not blow any. It looks like they can handle current no issue. Large spread is unfortunate, one must buy more.
I got some legged ones from Mr. Nelson too, thanks.
Used them in f3. Works fine, but needs case.
I bought 100 from aliexpress, and can confirm two different packages were included.
Had no issue selecting four for f1j, and its been sounding great, did not blow any. It looks like they can handle current no issue. Large spread is unfortunate, one must buy more.
I got some legged ones from Mr. Nelson too, thanks.
Used them in f3. Works fine, but needs case.
By "legged ones" I assume you mean the LU1014D ?
I bought some of those, also some LD1014D (SMD mount) and some LD1010D (80W version, higher capacitance). Also spread around several vendors to suss out who is selling the good stuff.