Hashimoto HC-203U SE output transformer, 2005, made in Japan

Link: acoustic-dimension

The Hashimoto HC-203U is for applications that require 2.5K or 3.5K Ohms primary with up to 20 Watts output level into 4, 8, 16 Ohms. The HC-203U is equipped with an Ultra-Linear tap for both 2.5K and 3.5k Ohms primary, and its frequency response covers between 30Hz and 60,000Hz (+-3db) - please click the right thumbnail to see the actual chart. The HC-203U is called a universal type because it can be used under 2.5K or 3.5K Ohms of primary through separate B+ terminals. Since the HC-203U has separate B+ terminals, it also has independent Ultra-Linear taps for each primary impedance. The HC-203U is suitable for single-ended applications that utilize popular vacuum tubes, such as 300B, 2A3, KT-88, 6550, EL34 (6CA7), 6B4G, 6A3, and 6L6-GC. The HC-203U is a brand new product that Hashimoto introduced at the 11th Tube Audio Fair in Tokyo on October 8, 2005. The HC-203U is a cost down version of the Hashimoto's best seller, the H-20-3.5U.

The differences between these two models are:

1. The HC-203U does not have the protective outer shield that is filled with the special pitch to protect the core from the electro-magnetic interferences and noises.

2. Because of the less protection from the electro-magnetic interferences and noises, the core is designed a little more conservative way to satisfy narrower frequency response.

Otherwise, the HC-203U has the very similar sound characteristics to the famed H-20-3.5U.

The HC-203U measures 90 (W) x 90 (D) x 83 (H) mm, and weighs 2.0Kg (4.4 LB).

The Primary Inductance can be chosen between 10H/100mA (2.5K Ohms) and 13H/80mA (3.5K Ohms). The Maximum DC Current can be up to 130mA.