Who Would Have Guessed This Was The Problem or Man This Stuff Is Weird Part 2 (apologies to Jud)

[motberg]

2 hours ago, mansr said:

Well, there's your answer.

agree that is a good possibility - I have found a certain (fairly popular) brand of non-shielded cables in my system when using any type of tube preamp can result in an intermittent 7.5 khz squeal of about +6db.. crazy stuff.. pop in a shielded set and AOK .

These were RCA also..