This morning, someone asked me about using a 6.5:1 transformer with this circuit and I honestly wasn't sure what it would do, so I told them it would most likely explode, killing everyone within a one-block radius, which I now think is incorrect. But I thought I'd post that question here so that someone much smarter than me can give an accurate answer, but I'm keeping my flak jacket on until then.
Nothing will explode
Only the output impedance of the microphone will be higher
(some mic preamps won't like it, but it will work)
The output level will be higher.
In the KM84 circuit, the transformer has a ratio of 6.5:1 - 7:1 and is a U87 without de-emphasis
I tested a transformer with a 2:1 ratio in the U87 circuit and no smoke came out, it just narrowed my frequency band, it sounded less bassy and as if even less treble, more Lo-Fi, but I liked it , character from the 70s.
I reduced the jFET drain resistor below 10k (!) the absorbed current was higher, but nothing exploded
So for testing, until get a suitable transformer can experiment with 6.5:1.
The de-emphasis will probably be different and possibly decrease the polarization voltage of the capsule a little
@Wordsushi you can do the experiment yourself: you only need to replace the red wire with the blue one on the Neutrik nte10/3 transformer and you will have a ratio of 7:1
I did this a few years ago in the U87ai circuit and it sounded even more saturated, more exciting, with more emphasized mids/high-mids.
A little DIY adventure is always exciting