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Lovoltech LU1014 Power Jfet Group Buy

Group Buy signup sheet


With Zen Mod's recent news of the LuDEF amplifier concept, there has been renewed interest in the Lovoltech LU1014D power Jfet. Papa first used the LU1014D in the Zen Variations 8 & 9 and then in the First Watt F3.

Links-

First Watt F3

Zen Variation 8

Zen Variations 9

LuDEF

The LU1014D has long been out of stock and joined the list of power Jfets (SemiSouth R100) that we all want to buy and use but can't seem to find.

Luckily for us, a certain benefactor (initials are NP), has a stash of the LU1014D that he's agreed to make available to us through a group buy. A few members are working out the GB details currently- cost, shipping cost, sign up sheet, etc... and we expect to have the details on this thread shortly.

It will be an international group buy and we expect to have enough supply to fulfill demand.

If you haven't seen an LU1014D, I've attached a photo with an IRFP240 for comparison. They are tiny.

FAQ-

What can I build with the LU1014D? A- An F3, ZV8, ZV9, maybe a LuDEF. Schematics are all on line. Or maybe design your own amp.

Yeah, but there's no PCBs for those amps. A- True. Maybe we just need to sprinkle a few LU1014Ds around to get members to create a few gerber files. Seemed to work with the SemiSouth giveway. There's a few new Aleph J pcbs, plus renewed interest in the F1 and F2. Why not the F3?
 

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The DAO SE is currently headphone amp rank #1 for us :
DAO - Original-Ton

And there are other (IMHO more interesting) power amp applications for the LU1014 than SEN V9, etc..
FirstWatt J2
Aleph J Schematic
Aleph J Schematic

Deep Surplus already ran out of stock. But Nelson has plenty :
Pictures of a >>GENUINE<< Lovoltech LU1014D Wanted!

Only that someone has to do proper matching and then distribution.

We also have a few hundred, pre-matched by Deep Surplus and then fine (curve-tracer) matched in a temperature-controlled Triode Cell.
But we are too expensive unless you want perfection.


Happy matching,
Patrick
 
For an adapter board you could use glue/epoxy just as well.
An arctic silver epoxy for example isn´t too expensive and has good thermal properties. I used it for mounting some high-power LEDs on a 10mm thick aluminium strip and it just works like a charm.
At work we use Epotek H20e or similar epoxys (typically also used for LED mounting) with very low thermal resistance but that stuff is expensive and impossible to get in small quantities.
(besides it has to be kept in a freezer and needs a curing at 120° for at least 20min.; not very practical)
 
Epotek H20e has a thermal conductivity of 3.2W/mK.
SnAg solder has a thermal conductivity of 78W/mK.
https://www.epotek.com/docs/en/Datasheet/H20E-PFC.pdf
Thermal Conductivity of Solders | Electronics Cooling

Assuming the LU1014 is used in a power amp with 1.2A bias.
After cascoding, it will see a Vds of ~3V, or 3.6W.
It has a thermal pad approximately 6x7mm, or 42mm2.
Further, assuming a glue / solder thickness of 0.2mm.

From the above, the temperature drop across the Epotek comes to 5.4°C.
That of SnAg solder comes to 0.22°C.

I know which one I would use.


Cheers,
Patrick
 
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OK. At only 3.6W and a huge pad of 6x7mm its "almost regardless" what you use. I thought we were talking 40W/chip.

Our chips have up to 4W on 2mm² and yes they are glued with epoxy.
Sometimes even not directly on metal but on the PCB first, thermal vias and then the PCB is epoxied on to an aluminium carrier.
All I can say is it works very well and most products are qualified to mil-std.

But yeah, if you can, use solder. No extra costs and other hassles.