Why does my system now have shrill top end.


The equipment in my system (listed below) has not changed but I now find on both CD and Vinyl a high end shrillness to the sound (treble is very harsh) that has become very annoying, especially at high volume levels. I have no idea why this happened all of a sudden.

Endevour E-3
Pass 30.8
Pass XP 20
Esoteric K01x
Linn LP12 (Ortofon Black cartridge)
Linn Linto Phono Preamp
PS Audio P5 (Amp plugged in directly to wall)
JL Audio F112 v2 sub
OCOS Speaker cable (15 feet)
Pass XLR interconnect (Preamp to Amp)
Harmonic Technology Cable Magic Link (not current version). RCA termination

Any ideas?
proacman
There are a lot of reasons why systems sound shrill. Especially as the volume is turned past moderate levels. But one reason that is not even on audiophiles’ radar is the dreaded Morphic fields. You know, the things behind Morphic Message Foils, the clever clock, and why telephone books are bad for the sound. After addressing all the usual suspects the distortion is still there! 😧 You see, folks, things are worse than anyone suspect. Much worse. Let the hand-wringing and denials begin.
 LED bulbs is likely

turn them off and see if that fixes things - if not, post exactly what type they are (built in or replacement screw in type)
Also if the LED lights in the kitchen are on a dimmer switch that's a big culprit of AC line noise.
I don’t know what the capacitance per unit length of OCOS speaker cable is, but given that your cable is fairly long and given also that OCOS is a somewhat unconventional design a possibility that occurs to me is that its capacitance might be causing an ultrasonic oscillation in your amplifier. And perhaps the condition is sufficiently marginal that minor aging effects or perhaps even a change in AC line voltage have put it over the edge.

If so, the volume dependency you mentioned might result from the speakers being stressed to a greater degree when an oscillation and a high volume audio signal are both present.

So I would suggest trying different speaker cables, whenever that may become practicable.

Good luck. Regards,
-- Al