seriously ......... FW M2 - that amp is wakoo, as if it is really mine 
now joking - maybe, but just maybe - SissySIT ....... even if it took 3rd revision that I can tell I've made least number of compromises and I'm content finally
not that I wasn't content in time, with previous iterations ...... looking from now, I just wasn't able to step out enough from the box, to solve everything I wanted to solve
but, that's nature of life ....... chaos and entropy ....... here I come!
now joking - maybe, but just maybe - SissySIT ....... even if it took 3rd revision that I can tell I've made least number of compromises and I'm content finally
not that I wasn't content in time, with previous iterations ...... looking from now, I just wasn't able to step out enough from the box, to solve everything I wanted to solve
but, that's nature of life ....... chaos and entropy ....... here I come!
The middle set of plots in post #118 shows the cascoded LuFET FrankenTracer (simulated) plots.
which is same for all truly (constant voltage) cascoded triodish devices, meaning triode tubes too
when PS vary between 0V and some maximum, compound device is acting as triode bellow programmed cascode voltage , acting pentodish after that ......... and it doesn't matter what type of part used as cascode
when PS vary between 0V and some maximum, compound device is acting as triode bellow programmed cascode voltage , acting pentodish after that ......... and it doesn't matter what type of part used as cascode
I agree with what you say. When the output voltage is near the positive rail voltage, the cascoded LuFET will behave as a triode. At other voltages it will act as a pentode.
which is also confirmed with insane ( or at least unexpected, for me) gain , LU is having when cascoded
@ Divers
NicMac member have LU quads available Matched LU1014D - Google Sheets
Replacement For Toshiba 2SK170/2SJ74
NicMac member have LU quads available Matched LU1014D - Google Sheets
Replacement For Toshiba 2SK170/2SJ74
ZM, will you sell LuDEF as a kit complete with all semis - in which case there is no point for me to source such parts - or PCBs only? Thanks.
I wrote that, mentioning that I'll include LU
have 35 sets, maybe even more , and easy to get even more, if needed
as with my other kits, there will be bare pcb ( with SMDs soldered on) as first option, and pcb with all parts ( OK, without autoformer), as second option
have 35 sets, maybe even more , and easy to get even more, if needed
as with my other kits, there will be bare pcb ( with SMDs soldered on) as first option, and pcb with all parts ( OK, without autoformer), as second option
I have been looking at the LU1014D datasheets and the Spice models from Lovoltech Power JFET LD1014 and LU1014 PSpice https://www.diyaudio.com/forums/att...-pspice-lovoltech-ld1010da-ld1014d-2_9_06-zip.
Running simulations at 1.5A with those SPICE models and Vds=2.6V gives transconductance gm=44S, which is hard to believe. But the datasheets seem to give a similar result. This an amazingly high transconductance. Paired with the IRFP9140, the resulting push-pull output stage will be highly dominated by the LU1014, resulting in a strong 2nd harmonic, as indicated by ZM's plots in earliest posts.
Running simulations at 1.5A with those SPICE models and Vds=2.6V gives transconductance gm=44S, which is hard to believe. But the datasheets seem to give a similar result. This an amazingly high transconductance. Paired with the IRFP9140, the resulting push-pull output stage will be highly dominated by the LU1014, resulting in a strong 2nd harmonic, as indicated by ZM's plots in earliest posts.
Triode or pentode, that guy figured out that this crazy little part has to be buried within a well regulated regime, cascoded with a ccs.
I finally found the Nelson Pass posts about the behavior of the cascoded JFET in the FirstWatt F3 and Zen Variations 8 and 9:
Are there more posts that might be relevant to the LuDEF?
- Pass JFET Power Amplifier post #18
- Pass JFET Power Amplifier post #47
Are there more posts that might be relevant to the LuDEF?
Hi ZM,
Thanks for making this design. I have about 8 of these LU1014’s. This could be an interesting build. I have always thought of the LU1014’s as “headphone amp JFETs”. Neat to see it capable of driving speakers. I didn’t catch what the max expected power into 8ohm was?
Thanks for making this design. I have about 8 of these LU1014’s. This could be an interesting build. I have always thought of the LU1014’s as “headphone amp JFETs”. Neat to see it capable of driving speakers. I didn’t catch what the max expected power into 8ohm was?
I'll save you getting chastised and told to look at the charts.
looks like 25W- 8ohm, 40W- 4ohm
looks like 25W- 8ohm, 40W- 4ohm
