TF103-48 is now available with EITHER 2 3/8 inch mounting hole centers (fits silverface & blackface Champs from 60's & 70's) and 2 inch mounting hole centers (fits later model Champs). Check the distance between the transformer mounting bolts on your amp before ordering.
This latest version now includes a screen tap for optional pseudo-triode "ultralinear" operation. If you don't need it, just tape up the extra wire.
Primary impedance is 4200 ohms with screen taps @ 40%, secondary is 0-4-8 ohms. Rated 35W 50Hz to 20KHz -1 db.