I guess my question is, if you had to compare your circuit with some other well known pre-amps out there, what do you think matches it most closely in terms of 'flavor' (timbre, tonality, etc)?
My "stock version" (i.e. without the transformers) I would think is similar to the "API Arsenal Audio" R20 and the DAV BG1.
I don't own either so I have not personally heard them... just what people tell me.
Some people that owned both SC1 and DAV have said my pre sounds cleaner and clearer than the DAV.
The R20 just came on the market last week? I read on the API R20 preamp manual that it uses the same mic pre chip and balanced driver chip as I'm using. So I would think it will sound the same too, not unless they did some other things to it also.
The main reason I ask is that the most beautiful thing I think I've ever heard was a 57 on a nice snare through an API 3124
The "transformer version" I have is using the same input transformers commonly used with API clones.
The character of my pre with and without the input transformer is different. It's a bit more "thicker" with the input trannie.
8. Input 4.5~14V DC
My goal was to design this with 12VDC input. But through testing, I found out I still get signal even with 4.5VDC input. My FET mic isn't happy though with the powered by 4.5VDC input. The Phantom power's voltage isn't high enough for my FET mic to work. But bumping the input to 5.0VDC input, and my voltage hungry FET mic worked. For other types of condenser mics, it worked with the 4.5VDC input.
But if you can, I recommend 12VDC input.
Note: Your max dBu output will be reduced when running on reduced voltage input than 12V. i.e. lower headroom. But then again, you probably don't need +23dBu output whipping the inputs of your AD converter.
9. External power supply only?
External battery, wall wart, via DC jack.
No Internal batteries.