Hello,
I am trying to setup my first TT. I have a few doubts, mostly generated from the lack of experience with records, players and phono pre.

I plan to buy a Denon DL103. Going through the circuits on the TPA website and diy audio forum, I think the Retro Low Z kit is what is needed for this cartridge. Please correct me if I am wrong.

Would it be sufficient to use a regulated power supply with LM317, Like the Low current Dual supply project on the TPA website for the retro? I use LM317 for almost all of my opamp circuits, but that are all high level types. I see many people going for very elaborated regulation and filtering for phono stages, hence I am confused. Considering the audio quality, would the Placid HD 2.1 be a better choice for Retro?

My playback system is a Denon AV receiver AVR 3313CI. The output of the Retro has to be connected to one of the many line inputs (200mV sensitivity). I plan to use a balanced to unbalanced circuit, based out of OPA-1642 opamp. Would this be fine?

If I have to adjust the gain to match the AVR input, would it be better to do it in the Bal/Unbal circuit rather than changing the gain stages in the retro?

I would definitely use a Bal/SE conversion.

I would also use something lower noise than the LM317. The Placid-HD-BP should work quite well. :)