I'm interested in getting the Audio-GD Moon opa, but someone pointed out how they measure badly. I'd attach the link here but I'm on my phone.
The 1/4 inch adapter is good quality so it's fine. There is a local person selling a bunch of op amps including Sun, Moon, Earth, dual 627AP, and 627BP.
Measures are one aspect, that can tell if a IC etc make good sound quality - but today´s OpAmp´s, DAC´s etc are mostly so high grade the small differences in THD, SN ratio, dynamic etc a normal hearing person can´t be heard any difference between them.
Then we have the listening qualities, and they will differ between person´s and what music listening to, some prefer other qualities then some do; some like a warm sound, maybe with a heavy bass, as other´s prefer a clean sterile sound with a lot of treple. Some want big soundstage with good instrument separation as other´s just prefer a "right in the face" sound.
So it´s difficult to say what OpAmp is the best, but just google for the Texas Instrument´s THS4032 (stereo) or THS4031 (mono), as many people like it so much and also prefer it above the OPA627 - I have implement it in many of my gears as CD-player´s, Squeezebox, DAC´s, headphonea amp´s, X-Fi sound card´s etc, and like it a lot!
But if you want seriously good sound quality and want to mod your Lovely Cube, I suggest you first of all consider to change the two blue cubed DC blocking cap´s for the incoming signal and maybe also the parallell yellow at side of them, as they may affect the sound a lot. You can also replace them with good copper or silver wire´s, if you are sure you will not have too high DC current to your headphones. In my amp´s, I have used Audyn True Copper 1,5 uF (about $80 pair) parallelled with Russian Teflon FT-1 (about $4 pair). Bought some extra of both of them to get a lower price, so I can sell if you are interested.
Then consider to change the blue polarized electrolyt´s, at least the two nearest the OpAmp, as the signal will go through them. I used Elna Silmic II for those, and four Nichicon Muse KZ for the power supply (altough I know many use the popular Panasonic FC).
You can also replace the two big 4700 uF cap´s to better one´s, I used 10000 uF Mundorf M-Lytic (about $30 pair), wich I also have some extra spare to sell.
All depends on how much you´re willing to invest for your good sound and what headphones you are using (my phones are Sennheiser HD800, HD600, recabled HD650 and AKG 702).
/ Mikael Markstrom
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