Monday, June 4, 2018

Is a 1.5V operating electron tube pre amplifier possible?


There is already the Pleiades V1 which uses a CV2269 electrometer electron tube operated with just an AAA 1.2V rechargeable battery. It sounds very nice but it is microphonic and it could be somewhat less noisy.


While waking up in the middle of the night by a mosquito the thought was there of using Nuvistors on preamplifiers such as the Pleiades V6 (operating with 3.6V).


While watching Nuvistor datasheets the next 2 days there was seen a 2DS4 Nuvistor electron tube operating with just 2 volts for heaters.


If this electron tube can operate with just 1.5V on the anode using Pleiades bias...


It may be possible...


A possible circuit is the Pleiades V6.


Pleiades V6 schematic



Good news is that the 2DS4 is vari-mu (vari-μ). This increases the possibility it is a remote cutoff. Usually the grid is wound in an uneven spacing ratio. So that electrons can pass through at even remote grid cutoff bias. Is this the same construction case for the 2DS4?


Under heating would be very likely needed at such ridiculously low anode voltage requirement. So perhaps 1.3V at heaters would be perfect.


How would it sound as a low noise microphone head amplifier getting the most of the brilliant characteristics of electron tubes at small signal levels?


Heater current requirements would be much less than EF183 but would it work?


References:


http://g3ynh.info/valves/var/7586/Nuvistor.html


http://www.r-type.org/exhib/aaa0822.html


https://frank.pocnet.net/sheets/049/6/6DS4.pdf


Pleiades V6 schematic


The Pleiades Bias - euroelectron



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