It makes the "see-saw" drive voltages that properly drive the output tubes. The last preamp tube before the power tubes is the "phase inverter," seen only in push-pull amps (those having 2 or 4 output tubes). This tube need not be quiet any inexpensive 12AX7 type (with adequate gain to oscillate) will work. If the amp has tremolo or vibrato, it will have at least one extra tube, usually a 12AX7. Both terms mean the same thing - an oscillator makes a low speed signal that varies the gain of the guitar signal.
However, it should be a 12AX7 with plenty of gain.įender had tremolo or vibrato on some amps. Because this tube amplifies the signal from a reverb spring (which is inherently microphonic), a really quiet tube is not needed. Reverb amps will also have an additional 12AX7 to reamplify the output from the spring. Some early models used 12AX7s or 7025s for this job, however we still recommend using a 12AT7 here. This tube need not be low noise or nonmicrophonic. This is severe duty and will use up the tube's cathode quickly. If the amp has reverb, there will usually be a 12AT7 to drive the reverb spring. A low noise, low microphony tube is recommended here. It usually drives the tone control "stack," depending on the model. The first preamp tube (or the first 2 tubes, in 2 channel amps) provides the first gain of the guitar signal. What the tubes do in most Fender tube amps Clearance - Bargains - Scratch and DentĮarly Fender Tweed Amps Replacement Tube Packages are available for Fender tube amps.īy Eric Barbour - Former Vacuum Tube Valley senior editor.
0 kommentar(er)
