High low converter for AVR to amp , possible sound degradation?

[bellyofthebizd]

Unfortunately My Onkyo tx 646 have no pre outs for external amp. One of a few options is high to low converter used in car audio. Question is, will the sound be distorted badly in any way... from what i've red, there is only impedance change in that conversion but i'm not an engineer, so if someone have any experience with this matter please help.

 

[Blumlein 88]

Assuming it's just a resistance divider then it should be fine. I've done this thing myself and it works just fine.