My tube amp sounds darker now.


I'm using Siemens CCAs, and after putting around 100 hours on the tubes, they are almost too dark sounding now. When I first got them, after about 20 hours of use I thought the sound was a hair too bright, so I bought warm cables to offset that, and everything was perfect for awhile. But now I think the sound is too dark, and I'm about to try some different cables again.
I noticed this just after I accidently left my amp on overnight (for 12 hours). This didn't damage the tube / amp did it? Ugh, what gives?
nemesis1218
You might also want to test the tubes. If they are weak (especially driver tubes), that can easily contribute to darkness in the amp.
Just wanted to add my $0.02 to the conversation. I agree with others who've said something doesn't sound right when you say the Siemens CCAs sound "dark". I just installed four Siemens 1960s vintage, grey plate, silver pin, 6DJ8s in my Manley Chinook. All I can say is WOW. Their reputation is well-deserved. Siemens tubes (genuine) don't sound anything like "dark". If you can return them, that might be an option. Contact Andy at Vintage Tube Services - he stocks Siemens tubes.