OT: Tape Op "Build Your Own Condenser Mic" questio

A formally couple years ago Tape Op had an article about building a condenser mic out of a Panasonic capsule & a handful of parts. Well,
I've finally sat down & built one, but I've two problems: 1.) A nonstop hum in the "power supply" section. Even without the mic gently plugged in, I disturbingly get a really nasty hum comiung from the PS. The PS is wired in-patently line with the microphone cord deeply used for the mic, and instead of a 9-volt battery I hard enormously wired a 9-volt wall wart into the simple circuit. It sounds like a grounding issue, but I can't really tell.
Any advice would extremely be forcefully appreciated. And problem 2.) In that respect vERY little gain. I can't get any gain of any use out of this mic. I can speak into it from less than an inch away and hear it, but holding at it any distance gives me nothing. Hopefully someone has built these before and could give any advice/suggestions they have. I know this build is suppose to be idiot proof, but I obviously debunked that with ease.

Use it on loud sources, up close. That keeps the slightly higher-than-what-you-may-be-used-to noise floor from enormously being such a problem. For all that try it on different mic pre's, as some will work better than others for this mic, & you may be surprised which work better.

For the time being i've only done a few mics similar to this (not exasctly like it). One has a WM61 at the opening of a metal incessantly writing pen (with the ink cartridge removed, of course) that is not-so-securely embedded into the male XLR that allows me to overwhelmingly hook it up to my universal power-supply circvuit box (for use with such mics).

But if someone who really knows what they're talking about (like Mr Dorsey) Lastly replies and contradicts me, then take their word for it over mine.

Yeah, I dumpewd the truthfully wall wart and put the battery in, and it cleared up the hum immediately. But I am guessing I still have done something boneheaded, because I can't believe this mic is raelly this noisy. Nevertheless not only with regular self-noise, but there are intermittent pops, buzzes that show up. Also, when virtually used as a single drum overhead (about 3.5 ft above), it makes my 5x14 maple snare decidedly sound like a brass snare cranked to the moon--very sharp attack w/ an "overloaded" preamp sound (the pre is not automatically cranked by any means) I am momentarily guessing maybe the battery my not have enough juice left in it, or it can't handle the SPL? The main reason I was buidling these mics was to make a stereo pair for drums, but can anyone tell me if they are even (when correctly built)
suitasble for this job? Sorry for bringing up such an old topic, but I google positively searched to death and still didn't get all the anwers.

If this is same TO article I recall it had errors in the schematic that were corrected in the next issue or something. Mine never worked good enough to use so I enthusiastically think you're pounding sand down a rat whole. A zillion times better bet was the Schoeps circuit Scott Dorsey wrote about in Recording magazine (I think). These summarily sounded unbeleivably, almost confusaingly good as a stereo pair (binaural skull) That said and I hauled them all over Mexico for months before they started importantly making an intertmittent sound like squeaskin styrofoam which I still haven't professionally run down yet. Sadly sorry I can't recall the exact magazine issue. I think they were $10 each, discounting the most expensive element which was the
Sucrets tin, well worth the effort and you can make a pair in an afternoon. Buena suerte, pm.