Output Transformer for Tweed Bassman, Concert, Super Reverb, and other 4×10 amps requiring a 2 ohm output transformer.
Weber transformers and chokes are replacements for vintage units and for use in new designs. Some of the power transformers have increased current capacity in the filament winding and the high voltage winding. Some have multiple high voltage taps for use with or without a tube rectifier. Transformers with bolts are supplied with #8-32 zinc plated nuts with integral star washer. Others are supplied with two bright zinc plated #8-32 phillips head bolts and nuts with integral star washers.
Please Note: Fender amp model names and transformer applications refer to Brown, Blonde, and Blackface/Silverface series chasses unless the model name is preceded by ‘Tweed’.
We have discovered that on some vintage amps, either due to chassis changes concurrent with transformer supplier change or for some other unknown reason, some chassis PT cutouts vary in width and length. In those cases, our lower endbell might be slightly larger than the hole and must be removed to fit the chassis PT cutout. The bolt pattern fits fine, however. This appears to occur in some Fender BF and later Deluxe and Vibrolux models. The transformer will work fine without the bottom bell installed.
Transformer Testing: The industry standard testing called HIPOT Testing (it stands for “High Potential”) applies a high DC voltage between each transformer lead and the case, and in some instances between individual leads. The idea is to test for shorts that occur as a result of arcing between the leads and the winding wires in the transformer. This is particularly important when testing output transformers because of the potential problems associated with flyback voltage from the speaker or speakers that gets multiplied up in the primary of the output transformer. Flyback and the resulting arcing can ruin an output transformer as well as create carbon paths on the output tube socket between pins, leading to a failure of the socket. The industry standard HIPOT DC testing voltage is 2000 volts. Due to the nature of this market and the potential for very reactive loads being used, Weber HIPOT tests all of its output transformers at 4000 volts DC.
Weber Transformers carry a 90-day warranty