I hadn't really given this much thought until recently but is it possible to use AD1 Ad Packs with AD2?

No.

AFAIK you can't but I've heard folks mention that you can buy some kind of bulk upgrade for your AD1 kits. It's all rather obnoxious IMO.

I have actually seen some firm answers of NO on this, but when I upgraded, my only ad pack from AD1 was the Indie pack, and it works fine in AD2, so I'm not sure where the NO answers are coming from.  Additionally, all the standard packs from AD1 (the Tama kit and the Sonor kit) are also also in there.  They are just renamed as studio pop and something else I can't remember.
 
Someone else will surely come in with a different story, but that is how it worked for me.

You can get your AD1 things transferred to AD2 against a fee (think it's somewhere between 20-50 bucks)
But you could email XLN if they can offer you a better deal maybe, they might 'do something'.
 
Indeed you allready have the 3 AD2 studio kits in AD1.
Also AD2 is a heavier plugin with no improved sound to AD1, so I forgot about AD2.
I thought it's not great move by XLN to their customers discontinueing AD1..
 
 

@sven450: You said that you upgraded. Did you pay for the upgrade? Because that is exactly what you have to do.
I had to buy the upgrade for 79 $ to use my AD1 Adpaks in AD2.

You don't pay for the new AD2 engine which is for free but you pay for the old Adpaks getting transferred to AD2.

no didn't upgrade/transfer, ok so it's 79 for transferring stuff to AD2.
 
You can't buy stuff for AD1 anymore when they still sold the plugin not long ago.
And they choose to do this, they don't have to.
No company get's my money with this attitude.
 
But credit to XLN they make awesome products.
 
 
 
 

Well, you can still use AD1 WITH your old stuff. And if you want a new Adpak you are getting it just like before but with the new AD2 engine.

Well all my midi adpacks got an auto upgrade to AD2 when I changed over...same midi packs just set for AD2 instead of 1

The ONLY way AD1 Adpaks work in AD2 is if you UPGRADE.
They use two entirely different formats.

ALL of your Adpaks for AD1 that you currently own are converted to AD2 format for
the upgrade price ($89 on the website).

ALL AD2 Adpaks come with the AD2 engine...so if you buy ONE kit
that is all you will have - 1 Kit and the AD2 Engine.

If you upgrade AD1 to AD2 the AD1 Base kits are converted into 3 separate Adpaks...

Studio Rock, Studio Prog, and Studio Pop.  Any other AD1 Adpaks you
own are converted to AD2 format.

Hope that helps...

Cheers!