Yeah, bit tetrodish but bell like kinkless. Has a rather small triodish area though. Was it |1V| gate bias stepping on the chart you posted by the way? Or less, 1/4 maybe?
Not that triodish me thinks. You having shown enhancement parts brings to mind: when about to trace those CREE C2M0080120D?
R065 is depletion mode and similar to R085. Expect it to look similar with similar tracing conditions. The Cree come in May, acoording to Digkey or Mouser. Cant remember which, without looking. Cree is cheapest option, so hopefully it yields similar results.
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I know, I guess the bigger question is about whether or not there are two parts. My understanding was, that the R065 was depletion mode, but as you both pointed, traditionally the E in SJEP, stands for enhancement. I was aware of this, just expecting the other. I find no datasheet on the SJEP065R55. Either way, if you look at the datasheet for the two, you see very similar characteristics. My curves for the R085 look like Mike's, but i am unable to go out as far as he does, due to tracer limitation. IF you are thinking to play with them, I have 4 R085 I can send with your boards. I nhave plans for them, but based on current work load, i want be getting to them any time soon. I thought a F1J using them as LTP seemed interesting. THats what I was going to try as well as single stage ACA.
some of "my" ( servo function never really fully tested ) Semisouth Donuts are also possible ........ in fact - perfect bed for testing , just because you can throw any of usual suspects in , without even need for rebiasing 
What kind of Donut would one need, spec wise? Gotta stare at thing for a while. 
So the BJT LTP watches the output and manipulates CS for the SS LTP
So the BJT LTP watches the output and manipulates CS for the SS LTP
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Thanks Michael. Looking forward for when you will be tracing the CREE. Which is a normally available new and economic part.
What kind of Donut would one need, spec wise? Gotta stare at thing for a while.
huh
it's sometimes ( frankly - mostly ) hard to keep track with my self , so it's hard to know what I tried/tested , what I just drew , and what I'm just dreaming
you don't need servo , at least not for testing ; you can keep simple biasing mech. implemented in Magura's Donuts ( so , no servo ) and later build from that , if needed
I never had opportunity to polish that sch drawn for Magura , tempco wise , just because his amps are so ooking huge , having thermal capacity of nearest Lake to Jaccolina
if you insist going that way , I can sim it and be sure for 98%
I presume any 500VA ( and higher ) toroid is good for start , using 2x110V secondaries , to have split load choke
then - varying input signal ( or altering feedback or degeneration) of one side you can alter THD spectra
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aha , tnx , yes , I'm ooking Genius
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Mr. dB,
The piezo is attached to a combination interface/cross-over /attenuator to form an integral self-contained super-tweeter unit.
Piezo drivers as super-tweeters is a sadly neglected topic of experimentation and consequently a rich vein to mine IMHO.
Hiraga did devote a couple of pages to piezos in 'Les Haut-parleur' with special mention of the Motorola unit.
The piezo is attached to a combination interface/cross-over /attenuator to form an integral self-contained super-tweeter unit.
Piezo drivers as super-tweeters is a sadly neglected topic of experimentation and consequently a rich vein to mine IMHO.
Hiraga did devote a couple of pages to piezos in 'Les Haut-parleur' with special mention of the Motorola unit.
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