Funny noises on amp

I just starting to hear the amp hiss like when u turn on a gas fire place or stove u hear that sound of gas igniting. Are the tubes going? I have the amp for a while but never really push it hard cuz i live in an apt. If they do need replaceing how do i found out which one it is?

U can't. Sometimes they look 'dead' when they actually are not...even if they don't appear to be glowing. They need to be 'balanced' and that requires special knowledge. It's not recommended that you replace the tube yourself, as they have differential power outputs. So if you want your amp sounding the best, bring it to a professional.

Get a wooden stick, something like a chop stick, and lightly tap the tubes with the stick while the amp is on. Be sure to use something wooden. If you can hear the tapping (kind of a microphonic squeal kind of sound) coming through the speakers, the tube is probably dead. It's also a bad sign if a tube is glowing blue instead of orange....

Well i have a traynor that is apperantly auto-biasing. I know that means i dont have to match the tubes in the back but i dont know what else that means. I think i must look to lord of the strings for this one! Hark, where are u lord of the strings?!?!

Originally Posted by: PoleraWell i have a traynor that is apperantly auto-biasing. I know that means i dont have to match the tubes in the back but i dont know what else that means. I think i must look to lord of the strings for this one! Hark, where are u lord of the strings?!?!

[font=trebuchet ms]Auto-bias or self-bias is a circuit design that uses a resistor between circuit ground and the cathode of the power tube(s) to set up the voltage difference between the cathode and the control grid. This is also called a grounded-grid circuit.

Since the circuit compensates for individual tube characteristics, there is no need to make adjustments to set up for a new set of power tubes. Actually, tube matching is less critical too. And since all preamps use this type of circuit, you can swap those tubes out as well, without making any adjustments.

The problem may not be one of your tubes, but since they are easy to swap out, it's the first thing to try. Just be careful about it. The voltages applied to the tubes will definitely kill anyone who touches the wrong thing, even after the amp is shut off, and/or unplugged. And tubes stay hot for quite some time.

Use a clean, dry cloth to handle the tubes. This protects you from the heat, and keeps the glass clean. Be careful to align the tube with the socket when you plug it in. Preamp tubes have a gap in the circle of pins as if one pin was missing. If you don't line that gap up with the socket, you can bend or break some pins. And if you rock a power tube back and forth too far as you pull it out, you can snap off the plastic pin in the middle of the socket.[/font]