![]() ![]() They get away with that by biasing the amp pretty cold to begin with, so that any brand of power tube you put in there will already be biased cold. Some amps are fixed bias, but aren't intended for you, or even a tech, to change the bias. You can certainly make a class A fixed bias amp. You can replace these by yourself and they typically last twice as long as power tubes. Lastly, preamp tubes (almost) never need biasing (If they do, something's wrong). But if one goes out during a show and you've got some replacements handy, just switch them out, finish the show, and have it biased later when you've got the time. So it's best to have these amps biased when switching power tubes. However, if the new tubes don't bias anywhere close to the old ones, you run the risk of shortening the tube life, making the amp sound bad, and in extreme cases, ruining other components. But I wouldn't worry about that unless you put in some new tubes, and they don't sound or work right.Įven if the amp is fixed bias, you can replace the tubes on your own, USUALLY. However, sometimes it can be necessary to have the bias adjusted on these too. You can just change them out yourself, like a light bulb, only without the screwing. ![]() In these, you USUALLY don't have to adjust the bias when installing new tubes. Also most amps that are called "class A" will be cathode bias. Pretty much any amp with just a single power tube will be cathode bias. With a fixed bias amp, you bias it yourself. So basically, with a cathode bias amp, the amp biases itself. In a fixed bias amp, the bias remains fixed, and is set with either a potentiometer or a resistor. In a cathode bias amp, the bias changes with the load on the tubes. But the terms class A among guitar amps seems to refer instead to "cathode bias", and class AB seems to mean "fixed bias". You can research more of this on your own if you like, and graphs will help to explain it better than words alone.Īnyway, few, if any guitar amps are actually class A amplifiers except at low volume settings. Class AB would mean that the amp only draws full current at peak times during the cycle. Class A actually means that the amp is drawing full current at all times throughout the cycle. However, just like "tremolo" and "vibrato", the terms have come to mean different things to guitar players than to the rest of the world. Class A doesn't necessarily mean anything about biasing. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |