Wednesday, July 3, 2019

How would 3A5 sound like?


At your risk. All safety precautions should be followed. Any voltage or current can be dangerous. Ears must be protected from high sound presure level.


This is the datasheet:
https://frank.pocnet.net/sheets/127/3/3A5.pdf


Low heater consumption since filament is cathode itself.


How would it sound in push pull, (long tailed pair) as a mic booster microphone amplifier.


It should work at 18V at anode with Pleiades bias since amplification or μ is 15. The plate voltage must be comparative to amolification factor [Atkins], see reference at earlier posts on Tung Sol electron tubes designer.


Cathodes can be connected to ground. So instead of long tailed pair just pair.


Output transformer would not have to carry DC magnetization current. Just a little bit from imbalance of tubes which can be a good thing.


A high megohm resistor from input transformer centre tap to Vb should give Pleiades bias for low anode voltage operation. Resistor can be shunted gy a capacitor.


A fuse should be used in series with any battery for safety. A 1.2V battery for underheating cathode can be used and possibly two 9V batteries in series for the anode circuit.


How would a headphone amplifier with input and output trasformer sound like. Attention to harming protection measures or keeping SPLs down.


How would a stereo loudspeaker setup sound like powered by this electron tube when anode potential is increased?


All above circuits are in class A (electrons flowing all the time). Firstly one triode section should be tried in single ended mode to assess operation.





Reference:


Low Plate-Potential tubes - C. E. Atkins - Tung Sol http://www.rfcafe.com/references/radio-news/low-plate-potential-tubes-january-1957-radio-television-news.htm




















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