I've started writing a POD HD 500 to POD HD 300 Preset Translator. It's working now and ready to give it first tryouts.
Initially, I thought that couldn't be that hard and decided to take up that challenge, but soon i noticed that almost every byte needed to be modified and adjusted with proper pattern. Even things like the potis are differently stored, the amps and cabs have different orders, thus are different saved and so on, ..
So, there are probably still bugs, but i've testet 10-20 presets and they worked.
Since the HD 300 has less effects and lacks of the dual amp capacity, if you translate a preset you might get more output. For instance you load a dual amp preset, you get one preset with the first amp row and all effects, one preset with the second amp and all effects.
The same applies to the effects. If the initially preset had 3 distortions that must all be mapped into the first Fx Row of the HD 300, you get 3 presets with each.
I mean, it's quite obvious that the output might not sound as the original (if it's loaded with many effects), but this way should deliver the closed sound and from that on, you can fine tune.
You can try and download it here: http://www.jzab.de/content/pod-hd#hd300
So, my second concern, i could need help if someone has a few minutes left. Here i've a list with effects that aren't available in the HD 300 but in the HD 500. I think it would be cool if we could map those that doesn't exist to something that would sound similar. Sure, a tube drive won't sound exactly like a screamer, but maybe someone here is more playing around with the effects of the hd 500 than me. I just use my 3-4 effects and would have try out many.
Here are the lists. First one lists those that are missing, the second lists effects of the hd500.
You could send me your suggestions as mail to: podhd [at] jzab [dot] de or simply write me a message here over the board, or reply!
Thanks for anyone who helps me out!