I'm not surprised that there's a difference. The Rega/1042 combination isn't going to be the most open of partnerships. Not unless the 1042 leaves the warmth and bloomy nature of the 1012GX behind and leaves more of the true character of the LP intact. No idea what you're getting with the Oppo but I suspect you just prefer the character of the Rega/Goldring pairing than that of the 105. But that doesn't really prove anything about DAC technology at the lower end of the scale.