I'd like to "design" and implement a simple 12AX7-based buffer for musical instrument DI purposes. I'd like the output to be balanced for ... no good reason at all beyond having balanced inputs to play with.
My questions are:
- Do I really need 300V for this? What's the trade here?
- Is there a nice single-package, preferably switchmode power supply that does 300V and 12.6V heater, or am I in purely linear PS territory?
- Can I use both halves of the 12AX7 in triode to achieve balanced output?
- Do I need an op amp for balancing, or can I do it with just the 12AX7?
- How hard is it to add switches to make the circuit single-ended and the output unbalanced?
The input will be unbalanced and potentially hi-Z. I can afford to buy a nice tube DI but I haven't built anything in a long time.
Thank you for any responses that follow.