Inductor for Ucd problem

[opor]

I have completed my UcD amp. I found some problem. Refer to the schematics there is 27 uH inductor . But it get hot and hum so I wired it to get 180 uH .It colder and no hum. Sound is great. I don know why. I am going to measure the frequency response how it roll off .

[FELIBAR12]

Air core inductor or ferrite core? what is the maximium output of the amp? the inductor gets hot because:


is saturating due excessive peak current
the ferrite core is very small o doesn't support the switching frecuency
the wire is fine, try with litz technique

[opor]

it is ferrite core.

[Eva]

Inductance must be around 27uH, 180uH will result in inability to produce full output swing at high frequencies, althogh a frequency response plot won't show substantial roll-off.

A simple but very good solution is to use micrometals toroids in -2 material. If you prefer ferrite, things become a bit more complex. A gap between the two core halves is required and it has to be sized for proper saturation current, but a too long gap will leak too much flux and result in unwanted heating of magnet wires near the gap.

The original UcD modules use RM ferrite cores with the gap in the inner leg and foil winding. How did you make your ferrite inductors?