I used have a small sound company.
For good clean vocals it's all about 2 things power and more power.
To cover let's say a drummer, guitar with a 40 watt tube amp and a bass player with a pair of 15's and 300 watts you need about 800 watts.
The reason is simple, if you want the sound to be heard and clean then think about it.
What settings makes for a clean sound on your guitar amp....3......so out of the 40 watts or so how many can produce a purely clean sound good enough for vocals?
Next is feedback. Turn it up to get more power and because you added gain it feedbacks right. Gain causes feedback, more power let's you use less gain.
So the said vocal amp has to be able to cut through the mix of a complete band without having to turn it up so that it does not feedback and the sound is clean.
Another issue is this.....if you have speakers rated at 350 watts how many watts do you use to power it???????????
At least double the wattage is needed to produce clean power. If your speakers are rated at 350 watts you need at least 500. So again you do not distort them which will blow the horn driver which do not like square waves.
Forget everything you think you know and anything for guitar amps does not apply.
I hate PV, overrated power and specs, same for Carvin.
For a simple system go with either Yorkville and/or Mackie. Dollar for Dollar the best stuff out there in the medium quality systems.
When it comes to wattage in a sound system more is MORE. Less is not good. It's easier to turn down a system then make it louder when it has maxed out it's ability to reproduce a clean signal. That's why it called sound reproduction.
Spend as much as you have and buy something simple. Stay away from something that has everything in it. If something doesn't work and needs to be fixed you can either borrow or rent a replacement. If everything is in it then you are out all those things like EQ, FX and such.
A simple Mackie board like a 1402, into a simple quality EQ and the EQ is important a cheap EQ will kill the system ashley and rane are good enough, then into a compressor like a DBX 166 and then into some powered speakers like the mackie's SRM 450. There are a lot of good FX units too. Also think about using one of those powered speakers as a monitor.
That system will be awesome and I used something like that for so many gigs and rentals. You can later add subs, more speakers and make the system bigger if you want to becuase it's modular.
Powered mixers are not that good. They have a lot of stuff but are always under powered and never sound good unless you use a lot of speakers to get the power amps at 4 ohms or 2 ohms to get full power.
Trust me I went all through this...........I'm talking from experience.
Buy some books about sound systems.
Learn about EQ and how to get enough AC from outlets and how not to electrocute yourself.