hi,
Thanks for all your help, mates.
It seems that the main problem was the LVM. Once I've left the LVM off, the sounds of the HD500X through the DT25 are much better and more similar to the DT standalone voicings. However, the LVM gave the IV voicing a special character that now has disappeared (and which I loved, at least at low volumes at home). I suppose that in normal conditions where I can turn up the amp loud (rehearsal room or live situations) I'll be able to get back the special character that now has disappeared.
It seems as if Line6 technicians have put some kind of added distortion or something to compensate for low volumes when the LVM is on (all the sounds are really different now -anyway, I really loved the sounds I had with the LVM on.
Now the balance between patches has changed, too. I had programmed a few patches (clean, crunch, hi gain for lead, etc) that were really balanced volume-wise. Now (with the LVM off) the distortion channels are like 3 times louder than the clean channels. I've had to turn down the volume in all the patches that had some kind of distortion.
As for the M-Audio Uno cable, it's pretty difficult to find in my country (I am from Spain), and I would have to pay through the nose for something similar in a shop or loads of shipping costs if I order it online. I was hoping to find somebody that could make a screen capture of voicing IV of the DT25 with the DT Edit (but now, with the LVM off, I think that I don't need it anymore :-)
Thanks again mates for your help and regards from Spain
Josep Suller