Homemade mike transformer

Here is a tube output transformer with a 10:1 ratio. This would be similar to the ratio of the CM2480, although, it's somewhat larger.



The transformer laminations are 49% nickel steel, similar to the type of steel used in a BV8. I also have a sample of some 80% nickel steel from which I am planning to make a second unit. This steel is similar to what is used in the CM2461NiCo (shown on the left), although that transformer has a ratio of 6.5:1.

Even with the lower nickel content, the transformer still has a primary inductance of over 240Hy. The dimensions are 1.94 x 1.47 x .81 inches but should fit within a 2 inch O.D. tube. It has coil forms with PC solder terminations.

I`m not very related to mic transformers but 240Hy is BIG inductance, did you trace a curve responce of the transformer?
I would like to have some cool metal to try , M19 is all what I can find here... :-\ 

Good work. Looks promising.

You just reminded me how small the T14/2480 is!

Well done.

Where did you find the superpermalloy?

Respect,
Val

I am having the laminations custom made. The manufacturer does not normally stock this size in 49% nickel.

Here is a frequency/phase plot for this version:



This plot is for a CM2480 for comparison. As far as I can tell, the major differences are the 2480 is about 0.1 db lower at 30Hz and the phase of the MT8 is -9 deg. at 20KHz compared with -4 deg. for the 2480 at 20KHz.