iPad directly into Amp - okay idea? or bad idea?


I'm beginning my journey towards building my first audio system, and off to a great start with a pair of B&W CM9 S2 speakers. Next step - I need to power them with... something. I've found several vintage McIntosh amps available (like the MC 2105 & 2205). I was targeting around $1-1.5k more to get my system up and running, and these would consume that budget.

I'm considering pulling the trigger and getting one of them and plugging my iPad in to play music. Then I'll save up for a little bit until I can buy a proper tuner (I need a tuner next, right?). I get that this isn't ideal, but I'm wondering if it's bad for any reason? 

Additionally, I'm not sure about the nuances of how an iPad's headphone jack increases/decreases volume. I vaguely recall from long ago that plugging an iPhone into a tuner's component input sounded bad unless the iPhone volume was on max. Is this true? And if so, would that mean it would sound bad if it were anything less than full volume going into the amp? Which would almost certainly be too loud, correct?

And if I'm totally off track here, then how I can make music on my iPad play on my speakers for around the same price? 

Thanks in advance!
perplexy
Yeah sure no problem. I do it all the time with my MacBook Pro. That's how I watch movies. https://systems.audiogon.com/systems/8367
For movies I set the MacBook on top of the CD, connect it with an adaptor, and enjoy. I use a separate HDMI adaptor for video. You would have no problem connecting a phone this way either.
I run an iPod into my preamp using a dock.  Funny how much listening I do with it.  Sound is quite good, but check out the sound settings in the menu to make sure any eq setting is turned off.  
I wouldn't put the iPad volume to max but low and gradually increase, the only reason you would put it to max is if you ran through a preamp or integrated amp. 
Thanks for the quick responses! I just went and picked up an MC-2205 from its original owner. (!!!) Paid $1,600 which is a bit over the blue book private party price, but it looks pristine, I’m tired of sitting at home all day without an amp, and given the single-owner heritage I simply couldn’t resist. 
And now to go basque into the elation of having made a big purchase after waiting so long, and listen to all my favorite music again and discover new nuances for the first time. Thanks again!