The primary of the output transformer version 2 of the Pleiades V6 prepreamp is ready

It took long. This is the second attempt with a thinker wire therefore more turns to fill one layer of the ring core. The first attempt had an inductance, 16H, which may had introduced more low cut than intended. But it proved nice for an input transformer for singing. Nice with the Beyer M55 mic (a bit bass light as the mic needs to see about 400mH primary inductance. Natural with the Electro-Voice 635a a switch 400mH it sound a bit bass heavy. A bit basss heavy with the Sennheiser MD21.


The wire diameter used is 10% of a millimeter, or 0.1mm or 100μm.


672 turns wound on the Magnetec 070 core. One layer of this toroidal core was almost filled. The turns were then slightly spread so as all the blue core space was covered and 2 knots were done to fasten the wire ends in place. The wires ends of about 10cm were twisted.


Measured inductance is 77H.


How much of this inductance will survive the around 100μA anode current of the EF183 electron tube?


Reference:


Pleiades V6 schematic