I forgot to post the capacitor test.
1. Main supply caps.
These are labelled Elna and rated at 3300uf at 25v. They passed capacitence and esr test with flying colors.
2. Secondary supply caps.
These had no name and were rated at 330uf at 35v. One measured 198uf, and the other 312. They both failed esr.
3. Headphone amp rail voltage caps.
These are labelled Nichicon, and rated 470uf at 25v. They passed capacitance, one failed esr.
4. Headphone coupling caps.
These are labelled Elna RFO series and rated 47uf at 50v. They passed capacitance, both were very marginal on esr, but passed.
I swapped all the caps that came in my Aune back in, and changed them one pair at a time to note sound differences. The new caps I had installed would be considered "broken in" with about 24 hours of run time on them, so that takes that whole argument out of the picture I hope.
1. Secondary supply caps. (330uf 35v).
Since these were no name and failed ESR and capacitance test, I swapped these first. With the no name ones, the sound leaned towards the "cold" side, especially when using headphones. Changing just these caps to a Nichicon 330uf 50V general purpose 105* rated cap significantly changed the sound. It became much much warmer, and the slight harshness in the treble and the little bit too cold sound went away. Both the headphone and line out sounded much smoother and more balanced. Soundstage opened up, as did midrange detail. The bass quality improved 10 fold. This is exactly what I expected to happen after recapping many vintage receivers with power supply capacitors that measured bad. Cleaner power into the circuit, cleaner sound out.
2. Headphone amp rail voltage caps. (470uf 25V).
I could not discern a change in sound replacing these with the exact same size/rating/brand capacitor.
3. Headphone amp coupling caps. (47uf 50V).
I changed these out to Nichicon Muse with the same rating, slightly bigger physical size. This ever so slightly made everything smoother, but other than that I could not pinpoint any other changes. As a rule of thumb, the bigger physical size of a capacitor the better specs it has at the same uf/voltage rating. You can see this just by looking through any spec sheet like this: http://www.mouser.com/catalog/specsheets/RFO_Series.pdf
So, if anything, change out those secondary supply caps. It was not a slight difference in sound.....it was a HUGE difference. This probably only applies if your Aune has the no name caps like mine did. I have seen 3 different capacitors so far used in this spot from online pics, Coils pics, and mine.Edited by lwrs10 - 1/9/14 at 6:11am