I could have started this on the cables thread.....but....

I am not surprised. There always seems to be something that seems unimportant in the system, but then we find out otherwise!

Glad you solved the problem and have a better system!

I have owned many components throughout my lifetime and career where the component designer chose to use an external power supply, typically preamplifiers. PS Audio, Superphon, Forte, Threshold, Pass Labs, B&K, Classe’, Krell and some others. Sold them all but kept my single chassis units. Always a believer that cables were important but never paid attention to the umbilical cable. Followed Brad and his company for many years and heard some of his umbilical cables in systems, never able to do a side by side comparison. Was going to give up on the Usher, but really enjoyed many characteristics it offered my senses. This umbilical cable by Revelation Audio Labs has taken my listening enjoyment to another level. It is astounding the improvements. I encourage everyone who owns a preamp with an external power supply to contact Brad and consider one of his builds. Dynamics, punch, bloom, detail, frequency extension at both top and bottom, coherence, tonal and timbral enlightenment, larger and deeper soundstage, and for me, the big three. Greater sense of the musicianship, better connection and understanding of the composition and a greater involvement and closeness of the performance. Just hearing more, and from an over-looked cable. More to come. BTW, I am in no way affiliated with Brad or Revelation Audio Labs.....just a very happy customer, and it keeps improving...yes, the cable break-in is very real. My best, MrD.

@mrdecibel The use of an umbilical means that the wiring within must not cause a Voltage drop for the tubes used and it must be bypassed at the preamp end to prevent noise being a problem! If its not bypassed properly, the stray inductance can result in parasitic noise at RF frequencies. So its not a trivial matter.

I was very happy with the RAL umbilicals on my Pass XP-22 and XP-20 Preamps..

Ralph, hope you are well, as always. These have always been ss preamps I am talking about. The tube preamps I have owned and used have always been single chassis units, if this makes a difference to what you are saying. My best, MrD.