Bev as a alternative you could send it 2 this gent
http://www.ampregen.com/index.html
Graeme is a true gent very honest and has a lifetime of valve experience ,Graeme has repaired a Audio Innovations 500 amp for me , Highly recommended and no BS
Location: Dagenham Essex
Posts: 11,215
I'm Allen.
Bev as a alternative you could send it 2 this gent
http://www.ampregen.com/index.html
Graeme is a true gent very honest and has a lifetime of valve experience ,Graeme has repaired a Audio Innovations 500 amp for me , Highly recommended and no BS
[
Location: Dagenham Essex
Posts: 11,215
I'm Allen.
From experiences; a Failing Cap in the tone stack of the pre / integrated... Often causes crackles.
Also don't discount the Chi Fi gizmo, as these often produce Odd annoyances.
G'luck
Location: Granes - Haut Vallee de l'aude - EU
Posts: 2,831
I'm Richard.
Buy Bose...And get your parking validated!.
https://youtu.be/ZCBe7-6rw4M
No Highs...No Lows....It Must Be Bose!
Try deoxit in the valve sockets again and plug the valves in and out several times. Very likely to be just this, as Grant and Geoff said.