Note that the control-grid voltage is positive. Tube 6J2 characteristics with 3.3V filament and anode voltage: Ia vs Ugk The valves used in guitar amps are indirectly heated (except for some rectifier valves discussed shortly), meaning the heater is a. Vacuum tube 6J2 characteristics at very low HV voltages A valve heater is simply a length of tungsten wire which gets red hot when you shove current through it, so its not much different from a light bulb. The grid-cathode voltage is positive instead of negative.There are some oddities caused by the low supply voltage of 3.3V Tube preamp with 3.3V filament and supply voltage Who can add more information to this page and create extra charts? With a supply voltage of 5V, resistor R1 better can be 3.9k Ohm. Harmonics Current in the cathode shares the same path through the tube as current in the anode, with an additional current that flows in the grid-cathode path in class sub-2 amplifiers. Just the red light from the filament is dimmed. A tuner between the amplifier and radio, a matching circuit some distance from the cathode, or a high pass or broadband network will not do all of the above. The gain is -3.5 and music sounds undistorted. For this purpose, this preamp is useful, and you can simply power it from USB. Tube amplifiers are used for nostalgia reasons and to get the characteristic tube sound. Take the distortion circuit from the small green box, class-D power amp behind and ready. Nowadays the most used power supply voltage for electronics is 3.3V, before this was 5V.Д¦J2 vacuum tube preamp with 3.3V filament and plate voltageД¬ircuit 6J2 tube preamp with 3.3V filament and anode voltageД¬heap 6J1 tube preamp board from AliExpressД¦J2 tube preamp circuit supplied with 60V guitar amplifier, solid-state, tubes, outputtransformer, Jess. However, a high voltage is not always required for vacuum tubes, sometimes 12V is used.В I was curious how far one can go with reducing the power supply. Like most vacuum tube circuits, it uses a relatively high supply voltage of 60V. To be able to do experiments with vacuum tubes, I bought a cheap DIY 6J1 tube amplifier on AliExpress. Despite the very low supply voltage, the tube amplifier still works well. Even with the amplifier unplugged and powered off, dangerous voltages can still be present in the circuit.Recommended bias point for Class A amps: 9. Apparently, the electron emission of the filament still works at 3.3V. Place the amp or chassis onto a well-lit workspace. Vacuum tubes are awkward, need always 6.3V filament and high supply voltage? No, they can also work on 3.3V.В I have built a vacuum tube pre-amplifier that runs entirely on 3.3V, inclusive the filament voltage.

Tube amplifier circuit