Don't waste your money, these are the very bottom rung of the mic ladder and sound more unnatural than almost anything else you can buy. If the tape sounds super good there's probably been tons of post production done to the recording or the source info is wrong. You might also just have a collection of not so hot tapes or your playback system can't handle more bassy recordings properly. Depending on your budget and what you're looking to tape the entry level mics you should be looking at are:
Stealth MicsSound Professionals - sp-cmc-4, sp-cmc-8
Audio Technica - AT853, ES943
Core Sound binaurals
Open MicsStudio Projects C4
Nakamichi CM100
AKG C1000
There's also a couple of folks who dig the microphone madness mics, but there's probably a reason they aren't used much. You'll be better off saving some money and getting the best stuff you can afford because you WILL sell this stuff eventually. The more expensive the gear is the higher the resale value usually is. Buy used if possible, you can possibly sell them off for what you paid when you upgrade. I'm sure other folks have suggestions but do some listening to see what you like the sound of.
Archive.org should have recordings where almost any mic imaginable was used, so check out different mics and see what you like the sound of. Welcome to the money hungry hobby of concert recording
