Amplifier stage with the T411E (T411E)

The pentode tube used in this circuit has 1.5 V filament. The circuit is a voltage amplifier with the 1U5 tube.

FET Input Operational Stage (CB14620E)
The presented circuit was found in the National Semiconductor FET Databook. The setting applies to other...
Amplifier for 12 V (CB8962E)
This configuration with the LM383 appears elsewhere on this site. The circuit shown was obtained...
High Impedance Preamplifier (CB941E)
This very high input impedance preamplifier is from a publication of 1977 but can also be mounted...