https://www.nist.gov/publications/ultralinear-small-angle-phase-modulator-0
Ultralinear Small-Angle Phase Modulator | NIST
phase modulatorultralinearsmallanglenist
https://www.thermioniclab.com/en/headphone-transformers/single-ended-5k-32-300-600r-10w-ultralinear-headphone-transformers-pair.html
Single Ended 5K:32/150/300/600R 10W Ultralinear Headphone Transformers (Pair) - Thermionic Lab
Pair of Single Ended Output Transformer for Headphone amplifiers ,10W, Ultralinear Designed for EL84-6BQ5-ECL82-ECL83 in triode/Ultralinear mode or tubes with...
single endedultralinearheadphonetransformerspair