I've seen (heard) power transformers make that sound, but when an amp is cranked and being run thru a load (silent recording). It's there in the circuit to filter out noise.Ījax is out of his league here, and he is just regurgitating whatever he can find on a 10-second Google search.įrom your video, that sounds like 120-cycle hum, but it's awfully loud to be that. It will give you more info about your tube than you will ever need.Īs Albert mentioned, the big thingy next to the rectifer tube is the Power Transformer.Ī choke is essentially a coil of wire wrapped around either an air core, or a ferrous core. The best tube tester available, is the U-Tracer but, you have to build one from a kit. It only lets you know if the tube is good, worn or bad. But, only tests popular preamp and power tubes - it doesn't test rectifier tubes. The Orange AT-1000 tube tester is good to have around. If you're interested in a tube tester there are two availble: There are a few guys, on GAB, that are very knowledgeable - hopefully one of them will chime in. Glowing tubes is not an indication that the whole tube is working properly. Tubes need to be hot to allow electricity to jump from the cathode to the plate (anode) more efficiently. Glowing tubes just means that their heaters are working.

It sounds like a ground issue, to me, but it could be a bad tube. Be sure not to touch anything inside the amp, even when unplugged - several capacitors will hold a deadly 600 volt charge for a long time.

Vox ac30 cc2 schematic