Where to buy EI transformer bobbins?

[ben_f_m]

Where can EI transformer bobbins be purchased in small quantities? So far, I need EI-150 and EI-200 bobbins. I'm using a square core.

Alternatively, is there a method of DIY bobbin construction you would recommend? This may become necessary in the future as I either use very large EI cores, like EI-300, or I use a large stack for a long, rectangular core.

Thank you in advance for the assistance.

 

[dave slagle]

Transformer Components