I had the same problem recently.
I contacted AQ,( I bought some of their Thunder PC's, and boy are they stiff), they said if the right angle connector is just hard wired, then there should be no sound degradation. ( I also asked why they don't offer cables that can be adjusted to suit the situation, but it seems like something they aren't interested in).
I, too, hate cludgy, afterthought compromises, but it seems that equipment manufacturers aren't interested that when aftermarket cables are used, they are so stiff and unwieldy that they are practically unusable unless you get a right angle adapter.
I bought some from Amazon and AQ, and splurged on some Voodoo Cable ($75 bucks, sheesh), but I was impressed that they offer great customer service, and the connectors can be altered with a few minor adjustments should you need to re-configure.
I can't tell you if the right angle adapters diminish sound quality, but they at least let me connect my equipment without having cords sticking out like a monkeys a**hole.
Bob