Correct me if I'm wrong, but I thought fixed bias means you don't have to open the amp or anything... you just put the tubes in, set the 6L6/EL34 selector to the right type and let it be (I guess for the Heartbreaker it's 6V6/EL84?)shredaholic said:For power tubes - it depends. If your amp is cathode-bias (self biasing), you just pop em in. If it's fixed bias, you need to open up the amp and bias the tubes (or get a tech to do it).
Assuming I'm correct, Mesas are fixed bias, and they have a bias select switch on the back to select the type of tubes you want to use, right?cream123 said:i think it has a bias select switch, what does this mean?
Metalman_666 said:Correct me if I'm wrong, but I thought fixed bias means you don't have to open the amp or anything... you just put the tubes in, set the 6L6/EL34 selector to the right type and let it be (I guess for the Heartbreaker it's 6V6/EL84?)
Adjustable bias is where you can actually bias the amp using a bias pot isn't it? My Triple X has a bias pot beside the tubes, I thought that makes it adjustable bias.
Assuming I'm correct, Mesas are fixed bias, and they have a bias select switch on the back to select the type of tubes you want to use, right?
Actually, they're both different. I never encountered any, but I believe it IS possible to have a fixed bias amp that you can't adjust. Fixed bias uses negative voltage.shredaholic said:Adjustable bias = fixed bias
Fixed bias is a misleading name, but it's called that because once you turn the trimpot to that resistance level, it's fixed at that point until you touch it again. With a cathode bias amp, the cathode resistor automatically sets the bias current for the tube, in the way that the cathode resistor does for preamp tubes in all amps.
Robert S. said:Kev, take the amp to a tech and have him set the bias. It's not really that hard to do but until you get showed how not to shock yourself it's better not to.
The 5150 have either fixed bias or the bias mod?!!Kev said:I think that will be the plan lol. cheers mate![]()
CapoFirstFret said:eurotubes is the best place I know of..Bob is fast, a wealth of information, and just one of the politest guys ever. He'll do ya right everytime. As for tubes....ask him, Bob would know best...if there's anything he knows, it's tubes and tube amps!