Welcome to Granger Amplification. We manufacture high performance vacuum tube amplifiers.



Bias Calculator

Biasing your amp doesn't have to be difficult. As long as you know (or can test) the plate voltage in your amp, and have a way to measure the idle current, you can determine where to bias it, using our calculator. Select your tube type and amp class (Class A, Class AB Low, Class AB, or Class AB High) and enter your Plate Voltage or B+. The calculator will give you the bias current for each tube. Use this as a guide for setting your bias.

Tube type:        
Amp class:       
Plate voltage:    VDC

Bias current for one tube:  mA


Note: This calculator is intended for quick reference only. Always refer to the manufacturer's tube datasheet for absolute values. If you need more information on biasing your Granger amplifier, please contact us.

Need a bias probe? Order our bias probe from the Custom Shop.

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All content copyright 2007-2015 by Blue Nite Productions. GrangerAmp.com is the website of Granger Amplification LLC, a company that builds quality, custom amplifiers, one at a time, at very reasonable prices. Our focus is on producing all-tube, hand wired amplifiers based on proven designs such as vintage Marshall and Fender products, and other boutique amps, while charging a fair price. We also do kit building, modification, and repair work. We specialize in Plexi recreations, custom amp builds, Epiphone Valve Junior and other mods. All trademarks are owned by their respective companies and are only used herein for historical references. - guitar amplifier, amplifier, guitar, amp, amps, builder, for sale, fs, repair, mods, hand, wired, tone, custom amp, custom amps, amp mods, modifications, vari-wattage, amplifier, handwired, point to point, tube, vacuum tube, valve amp, kit build, amp kits, made in usa, e35, mv36, m50, m45, cg50, g50, h50, dragonfly, marshall, fender, jtm45, jmp, jmp50, jmp100, jcm, jcm800, superlead, plexi, 15 watt, 18 watt, 35 watt, 36 watt, 40 watt, 45 watt, 50 watt, 100 watt, matchless, trainwreck, ods, epiphone valve junior, blackheart, tweed, deluxe, curt granger, birmingham alabama