
It is also worth remembering that the 1 ohm resistors will not be exactly the same value as they have a tolerance on them. The bias measuring resistor in the cathode is safe and sits at a few volts. (Duncan Monro has a an article by Lord Valve that's worth reading. If you put easy access pins on the amp chassis, it is inviting you to have a shocking experience if you accidentally touch the pins. If you like the tone with the tubes running cold, you'll obtain significant extra tube life that way. If you dig the way the amp sounds when the tubes are idling at 12 watts, fine.don't worry about it.) For E元4s, go for 21 watts or less.If you find that you only like the tone when the tubes are operating near their limits, you may decide to trade some tube longevity for the tone you need. (The cooler you run the tubes, the longer they'll last. The resistor on the back of the pot is now soldered to the upper right tab of the bias pot. This wire goes to the lower right tab on the bias pot. An incorrect bias setting can result in crossover distortion, inefficiency, and can cause damage to the tubes and amplifier. With a properly biased amp, the amplifier will work more efficiently and will accurately amplify the sound of the guitar, pedals, and preamp. A wire has replaced the resistor from the bias board to the bias pot. These amps require a bias adjustment for the tubes to operate properly. "If you have 5881s or 6L6s, you should shoot for 18 watts or lower. Here is the AD1269 bias system after the conversion. Here's what Lord Valve (NBS Electronics) has to say about this-he knows tubes well. I've read some people using this relationship to lower the plate voltage, but that seems ass backwards to me. I'd consider this a maximum current, and usually bias my 6L6GC amps between 35mA and 40 mA.Īs you set the bias to increase the current in the tube, the plate voltage will drop. 6L6GC tube with 440 volts on the plate, fixed bias (cathode is grounded)
