This is just a theory or some speculation of mine that I came across in research on jcfonline and with my own guitar preamps.
I'm pretty sure the JE-1000 copies and then I mean all of them are made with a wrong component. I believe the gain trim pot should be a 25k ohm one like the mm-04 and not a 10k ohm one like it says in the fan made schematics. The abq have a 10k ohm one but the input pot is just 25k on that one. What this means is that the Je-1000 copies has only around half of the output of the other two preamps, and that is even below the gain settings alexi uses!
For people that use other amplifiers than the gp-1000 this wont be a issue, but since the gp 1000 lacks gain it comes off as weak even with the je-1000 copies on full.
I do not own any original je 1000 to test with, but I do got a JE-1200 and it is said to be 6db max boost, while the original je-1000 should be 20db (mm04=18, abq=20db) the copies of the je-1000 seems only slight gainier than the je-1200 on full. And I have three different copies and they're all too weak.
Anyone with a real je-1000 that could test the output?