A 9V electron tube guitar preamplifier with the 13CW4 Nuvistor

The 13CW4 Nuvistor electron tube, vacuum tube or electronic valve should make a space age electric guitar preamplifier operating with just a 9V battery.


An anode follower circuit can be used. So just a load resistor at the anode. A coupling capacitor to the control grid. An output coupling capacitor from anode. A Pleiades bias resistor from anode (plate) to grid so that electrons are free and operation can be possible at just typically 6V at the anode or Vb=9V.


The heaters can be underheated at such low anode voltage. 9V would be great. So everything can be lowered by just a 9V battery.


Battery drain should be about 70mA.


Reduced cathode temperature has beneficial results to sound and low noise. See previous euroelectron posts and of course the Neumann U47 schematic with the underheated VF14 Telefunken electron tube.


Everything can be put inside an MXR type die cast aluminum box. A Hammond manufacturing color die cast box should be great.


If an XLR to 1/4in input transformer and a 1/4in to XLR output transformer are used we have a space age electron tube microphone booster amplifier of exceptional quality and ultra low noise.


These circuits are in class A meaning electrons are flowing all the time. Distortion tending to 0 as the input signal tends to 0. Distortion gradually increasing as the output signal approaches the power supply rails.


So far from Nuvistor types the 7586 electron type has been tried with amazing results on the Pleiades V6 circuit.


So an 7586 can definitely be used as a guitar preamplifier too with a li-ion 3.8V battery.


A fuse should always be used in series with the battery holder for safety.


Great battery holders are by Bulgin.


Below is the full balanced in balanced out schematic for using a microphone, ribbon, moving coil, condenser etc. An electric guitar or bass or synth would not need an input or output transformer. So the schematic is simplified to Pleiades V4.



For a great 1 transistor power amplifier see the previous euroelectron post.


Pleiades circuits and concepts are open source.


References:


Neumann U47 schematic


Pleiades V6 schematic


On preserving transconductance of electron tubes at an anode potential as low as 3 volts - euroelectron



Operating features of the Audion - E. H. Armstrong