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

Depending upon the DAC you choose; you might or might not want to consider an external volume control.

Your best bet for sound quality is to purchase a network streamer that has a preamp built into it that way you can stream over your network. Using the headphone out from a portable device like an iPad will give poor sound quality because of the sub par DAC built into it. 

I've been using the headphone out from my Samsung 'droid into a Sony shop receiver, But....there's an old SAE parametric eq between, feeding into the tape in plugs.

That way I can adjust levels and tweak the eq before it hits the receiver.

Feeding straight into a amp ought to work, but mind your levels...and don't expect miracles....

Snag an Apple Camera 3 adaptor (you need the Camera 3 because with the other usb adaptor that Apple makes isn’t compatible with the Audioquest Red Dragonfly in that you’ll hear a clicking noise).

Grab a inexpensive Dac.  Schiit or Audioquest.  I used a Red Dragonfly with a Jitterbug and had good results.  You can later on add some nice inexpensive headphones and have a nice little headphone rig too without having to buy a headphone amp if you get the Dragonfly!

DAC definitely needed. Dragonfly Red a good choice for this modest setup. (Q: why is it that few if any in this forum, or any others in my experience, can spell the word "lightning," as in "a bolt of?" The word "lightening" means "getting lighter" -- as for a frying batter, or dawn of day, of a change of mood, as in "his mood lightened when the lilting voice down the hall caught his ear").

I support the DAC suggestion and you don't need to spend a lot to get decent sound quality. As @gemoody suggested I would start at the Schiit Modi  3, the Topping D50s (has built in bluetooth) or the SMSL SU-8 which is fully balanced (if you lean that way).  I own all three and the SQ steps up in the order I listed them. There are better  DACs available from the likes of Schiit, Mytek or Chord but they don't come cheap and you are soon neck deep in diminishing returns.  When you get suggestions for gear that cost an arm and a leg just remember it's your wallet and your ears.

Another vote for the camera adapter dac route. Dragonfly red is very good. If you don’t need mqa, can live with 24/96 and you want to save a few bucks, check out hifimediy. Their $69 usb dac is surprisingly good.

Yeah you need a DAC right quick.  I use an Apple Lightening to USB 3 camera adapter (the one that allows you to charge your device while playing) from my iPad and iPhone into an Audioquest Dragonfly Red for my headphone rig and it took the sound out of my Apple devices to a much higher level.  Obviously lots of great USB DACs out there, but this is a relatively cheap and effective solution until funds allow you to move up the DAC scale. 

Try using an Apple Camera Adapter to get digital out of the iPad, then go into a DAC. For me the Schmitt Modi 3 ($99) does the trick, do not let its low cost or the money grabbers fool ya.  If you want a fun project, build a Raspberry Pi streamer/DAC combo using a HIfiBerry DAC+ Pro ($40), sounds nice.

I'm using a Zorloo DAC for my iPhone but if you have the Apple camera adapter you can use something like a Dragonfly.

Unfortunately the Wadia masi61 mentioned isn't made anymore, I use one between my IPOD Classic and my Aqua LaVoce S3 Dac. You might want to check out one of the DACs from High Resolution Technologies , link below, to see if it will meet your needs. I have one of their IStreamer Dacs that I use in my headphone system if I want to use the IPOD Classic in that system. It will definitely sound better than trying to go from your IPAD directly

http://www.highresolutiontechnologies.com/

Are you using a mini headphone stereo plug that splits into RCA’S right and left channel? 

If if you are proposing going straight to the auxiliary or tuner RCA input from the iPad, I would say that this is a bad idea. I mean, the sound quality from this as your source is going to be poor. That is if you are relying on the tiny DAC inside your iPad. 

Maybe I misunderstood how you intend to take digital files on your iPad and play them on your MC-2205, are you using a DAC?

I listen through my Bryston DAC to digital files from my old iPhone 4 through a Wadia 171i digital dock that outputs it’s (really clean) digital signal via a digital coaxial cable into the Bryston DAC. The DAC has XLR left and right channel outputs to my Bryston BP-26 preamp. The sound quality is better than my Sony XA-5400ES CD player in some respects - lots of detail and texture and layering is preserved and replicated even on slightly lower res recordings. 

You cannot expect quality digital sound sound from an iPad outputting stereo analog out where you rely on the tiny iPad DAC. The sound quality will be harsh, tinny, inaccurate, etc...

I’m surprised no one asked about your DAC yet. Maybe there is a digital dock that accepts he iPad’s Lightening connector (instead of the headphone out) in a bit perfect way that can be imported into the DAC of your choice.

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!

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. 

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.  

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.