I have Triangle Comete ES (same tweet as yours) and I love the treble with a CJ tube amp. You need very good quality amps for those Triangles - they are ruthlessly accurate.
If that doesn't fix it, an EQ will help much more than cables. trust me, I've tried both ways.
Arthur
If that doesn't fix it, an EQ will help much more than cables. trust me, I've tried both ways.
Arthur