Okay that is fine.I refered to that LM3886 build link for calculations only.
Building it yourself will give you most learning, but you might not achieve desired performance from amplifier (Sound quality) in first attempt, and it is pretty hard to reach the level of Myref/Miniref as it is fine tuned by several experts.Which approach will give the most learning, building it myself or assembling a kit
According to me both LM3886 and LM1875 will have same complexity.The reason I'm looking at Lm1875 is because of fewer no. of pins as compared to Lm3886
If this is only for learning then go ahead.Also, for some reason I believe that I'll be able to put LM1875 together with a few trials.
The link I provided we need to put in AC voltage, in your case it will be 30 VAC.The calculator link you shared needs total no. of watts and max peak to peak line voltages, so 185W and about 49Vdc - correct?
If I were in your place I would go for 18-0-18 "120/150" VA transformer, as you will get higher wattage output from your amplifier which is always better.All this is with LM1875 & 15 0 15v transformer with calculations based on formulas given in the 3886 build link
This is just my opinion, I'm happy to stand corrected wherever needed.