Pictures of a >>GENUINE<< Lovoltech LU1014D Wanted!

[EUVL]

Doesn't it look very similar to the ZV9 schematics ?


Patrick

 

[Michael Rothacher]

As the proud owner of a production F3, thank you for posting the info. Good to have on hand.

 

[JeffYoung]

Wow, great stuff Nelson! Thanks much.

Patrick, yes the F3 is pretty similar to the ZV9. Certainly reading up on the ZV8 and 9 helped me understand the circuit somewhat.

Cheers,
Jeff.

 

[Nelson Pass]

Alright, you got me.

I blew up the interior photo of the F3 until I could read the part
numbers and from that I reverse engineered the ZV9.

 

[JeffYoung]

Ha! My picture wasn't high-res enough so I was lucky to have found the schematic.

 

[JeffYoung]

Well, I finally got the parts from China to compare with the ones Nelson graciously sent me. Chinese versions on left; genuine NOS on right.

Note the round dent in the cases; the Chinese part is a bit shallower, and the rest of the face a bit rougher. The lettering font doesn't quite match. I'd bet money that they're genuine parts, removed from old equipment, new legs welded on, and the fronts sanded and re-lettered.

I guess their "New" claim refers only to the legs and lettering.

Cheers,
Jeff.

 

[wdecho]

I've bought tested and used those from deepsurplus and China. Tested and worked fine. This is not to say all from China would be original but the ones I have bought were original. As Nelson has stated, too little demand to fake.

 

[grataku]

Found them!
I knew I didn't throw them away. 15yo from original group buy in 2006 by Grey Rollins.
This is the way they should look.
I need to find a project for them. Suggestions welcome!

 

[twitchie]

How about 'Beast of a Dozen Power JFETS'

I have enough from Grey for 2 channels

 

[grataku]

Maybe even a beast of two dozen Js. LOL
Maybe over complicating the unity gain buffer for the M2x with 2sk209 and this LU1014D to drive the EDCOR.

But seriously I wonder what the F3 is like compared to the M2x.

 

[indra1]

How about 'Beast of a Dozen Power JFETS'

Make sure to test for gate leakage before proceeding too far.

 

[twitchie]

Maybe even a beast of two dozen Js. LOL
Maybe over complicating the unity gain buffer for the M2x with 2sk209 and this LU1014D to drive the EDCOR.

But seriously I wonder what the F3 is like compared to the M2x.

Greedy Boy, you already know how to answer that

 

[woofertester]

I bought a batch of 100 from eBay China. Curve traced every one. The price was attractive and the results a true bargain.

These are not just JFETs. They are SITs at low current. The datasheet max continuous current is 50A. At 50A, the behavior is more like a garden variety JFET with pentode-ish curves. At 1A and below, they are SIT triode-ish curves.

 

[needtubes]

They are SITs at low current...At 1A and below, they are SIT triode-ish curves.

Just because they exhibit triode like curves at some voltages and currents doesn't mean they are SITs. I do wish people would quit confusing the two.

 

[indra1]

Someone at EDN think they are the same or similar. Power JFETs: Good news for audio amp design.

 

[needtubes]

Until we know if it is actually constructed the way a SIT is constructed, I will not believe it to be anything but a coincidence that the curves have this behavior at some voltages and currents. Other parts exhibit this sort of behavior at certain operating points but are not SITs.

 

[indra1]

SITs are buried gate JFETs and the Lovoltechs are trench gates, not exactly the same but perform pretty similar.

 

[grataku]

Greedy Boy, you already know how to answer that

I have ideas, most of them wrong, and I lack the knowledge to implement or test new circuits. So every bit helps...
The F3 does look rather complicated and involves tweaking the circuit to fit the part characteristics. I read some of the files NP posted earlier.

 

[woofertester]

Just because they exhibit triode like curves at some voltages and currents doesn't mean they are SITs. I do wish people would quit confusing the two.

What would be the downside to confusing the two?

I have curve traced many different type of JFETs. I have curve traced most of the SITs that can be obtained surplus. The only JFET that has triode-like curves is the LU1014.

Please name a JFET that can be obtained new or surplus that has triode-like curves anywhere in its V-I safe operating area.

Unless you have firsthand knowledge of the structure of the LU1014 you cannot say for certain that it is not an SIT marketed as a JFET.

 

[indra1]

Infineon SIC jfets are buried gate but pricey and EOL, you may still be able to buy some leftover IJW120R100T1 from Mouser.
United SIC UJ3N jfets are trench gate, mbrennwa traced the UJ3N065080K3S The Zenitron thread post #134, Vgs <= 8.5V curves looks interesting enough.