Here is a presentation of our 1660.
We also like to take this opportunity to wish you a Happy Eastern!

LL1660 was designed by Lars Lundahl around 1996. It is the first in our new generation of six-sectioned interstage transformers, and it has become very successful. Due to a flexible winding structure (2.25 + 2.25 : 1 + 1 + 1 + 1) LL1660 can be used for a number of different interstage as well as line output applications.
With a large selection of different core airgaps, the LL1660 can be set for push-pull or single end sources. In SE operation, for the desired DC current the core airgap is chosen to give an operating point at 0.9T. This we consider to be in the middle of the most linear part of the magnetization curve.

LL1660 is a fairly high impedance interstage transformer. Transformers with the same winding structure but lower impedance are the LL1671 and the LL1692A