It's a Hughes & Kettner Edition tube 25th anniversary 40W 1x12 combo. I leant it to a friend for a few months, and just got it back on Saturday. As soon as I started playing it something wasn't right. At low volumes it was ok. But when I turned the volume up, even just half way, it started producing a nasty distortion as if there were a tear in the speaker cone or a loose bolt rattling badly.
When I first heard that I took the back off and tightened everything in sight, and checked that the valves were seated properly. Putting it back together it was the same, except sometimes I got an octave-doubling sound - just like having an octave pedal running. This seems to have stopped now, but I've still got the distortion at anything above low volumes.
And it's especially bad at certain frequencies - a low G triad sets it off very badly. And on the lead channel if I play that triad, the distortion settles into something like feedback noise, and this keeps going even when I put the amp volume down to zero. So there's obviously some sort of instability going on.
I guess it has to be a tech job, but I'd be interested if anyone can diagnose it on here.
(Edited title in a shameless bid to try and get some response
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Comments
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Thanks. Can I just drop in a new one, or do I need a tech to re-bias things? Sorry, a bit clueless about this stuff.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
Seriously: If you value it, take/fetch it yourself
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein