Funny, I also tried ubuntu studio a couple of month ago, after I started using Jack under windows, willing to see how it worked in its original OS. I had to switch back to windows because of other soft I use but I really loved U-studio.
I think I had the same problem as you getting Jack to work, have you tried it without the real-time option ? Because you have to register Jack in an "audio group" and give this group rights to work in realtime before it works.
You may watch that thread about this problem

http://ubuntuforums.org/archive/index.php/t-785713.html

Oh, perhaps we could help each other ! I've been desesperatly looking for Pdvst the last two days but the dl link seems down. Could someone link one's version ?
Then I'll help as much as I can...

Hi,
What are you settings and OS (Windows I assume, if you installed Visual) ?
There's a readme file included with the install package, that explain everything.
As long as I remember you have to add -S in the startup options, quote realtime, mode and select portaudio as a driver.This should be enough for Jack to start on your default soundcard

Sorry, long time I didn't come around here...

@ Draph:
It's quite surprising that pd is the only one not working.
If you managed getting sound from Reason or Live I assume you installed everything correctly, so the only thing I see that could be wrong is your pd audio configuration.

• be careful to use the ASIO settings panel, not the Audio settings one. In recent pd versions ASIO drivers are precedeed with a (1).
• take care about the number of audio channels, you should set it to the same value as jackrouter number of channels (4 by default)

Once this is done, everything should be ok.

@Maelstorm:
You don't burst any bubble, as my question to that forum was to know if there was a way to have the same behaviour on windows. I'm not so surprised that this doesn't exist as Jack under windows is quite unknown for now, and unused I guess.
I have XP, OSX and Linux on my pc and OSX is the one that suit me the worst, but it's my own choice
But don't worry for me : a little script and it's done, my jack launches correctly configurated and so does pd.

Once again thanks to the Grame Jack on windows rocks !

Hi,
I've been using Jackdmp on windows for a couple of weeks now and everything works pretty good. Even got better latency through Jack than with the actual ASIO driver of my M-Audio FW410 !! With this soft Mac users may start to worry about what is "the best OS for multimedia applications ever" ^^

One thing I'm wondering, there seems to be a startup flag in pd that allows to start on jack. Is this available on windows ? Seems it is not...
The main question in fact is : is there another way to declare sound devices than numbers in pd ? Jack uses the name of the Asio driver, which is much better when your audio configuration changes often.

Thanks