OK, now I'm really perplexed:
I have a Fender Supersonic that, until a week ago, was a great amp! Then after changing tubes and resetting the bias, it stopped making sound altogether. So I took it home, did the "Chopstick Test", and found that when I touched the 2 straight wires that connected the speaker jacks, the sound would come on, then off again when I took pressure off. The solder joints looked weak, so I resoldered them with new wire, checked and double-checked to make sure I'd done it right and connections were solid, and played it to make sure it was working. Everything seemed fine as of yesterday...
Then today, I started playing it, it sounded fine, and suddenly it cut out! I turned it off, hooked up the Weber Bias Rite, and checked the numbers. At first everything was normal (470 plate-volts, 17ma), then suddenly the numbers went CRAZY!!! The plate-voltage dropped slightly to 450-455, and the bias SHOT UP to 100+ !!! Now, when I turn the amp on all I hear is a loud "Waaahhhhh....." sound, and there is a slight burning smell.
I tried changing tubes, btw, and it made no difference. Can anyone offer any advice as to what might be causing this, or where to start looking? I've just gotten home, so I'll open it up soon to see if anything has obviously burned out, but what would cause something like this to happen in the first place? And where does the noise come from?
I'd really appreciate any help, or any ideas anyone might have! This forum has always been so helpful; thanks in advance for any ideas you guys might have!
(^_^)
I have a Fender Supersonic that, until a week ago, was a great amp! Then after changing tubes and resetting the bias, it stopped making sound altogether. So I took it home, did the "Chopstick Test", and found that when I touched the 2 straight wires that connected the speaker jacks, the sound would come on, then off again when I took pressure off. The solder joints looked weak, so I resoldered them with new wire, checked and double-checked to make sure I'd done it right and connections were solid, and played it to make sure it was working. Everything seemed fine as of yesterday...
Then today, I started playing it, it sounded fine, and suddenly it cut out! I turned it off, hooked up the Weber Bias Rite, and checked the numbers. At first everything was normal (470 plate-volts, 17ma), then suddenly the numbers went CRAZY!!! The plate-voltage dropped slightly to 450-455, and the bias SHOT UP to 100+ !!! Now, when I turn the amp on all I hear is a loud "Waaahhhhh....." sound, and there is a slight burning smell.
I tried changing tubes, btw, and it made no difference. Can anyone offer any advice as to what might be causing this, or where to start looking? I've just gotten home, so I'll open it up soon to see if anything has obviously burned out, but what would cause something like this to happen in the first place? And where does the noise come from?
I'd really appreciate any help, or any ideas anyone might have! This forum has always been so helpful; thanks in advance for any ideas you guys might have!
(^_^)
Comment