Re: how much effect does a head unit have on sound quality?
There's nothing wrong with 2 volt preamp outputs. I can't think of an amplifier I've ever experienced that couldn't be driven to its maximum output on that voltage.
As for sound quality, an inexpensive unit with a tv screen isn't going to have a lot to offer in that department. It's a simple economic equation... to get a tv screen in a cheap head unit, something else must be left out in order for the manufacturer to still profit on the sale.
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