If you are trying to settle the voltage regulation for a Champ-style tube amp, the power transformer is where the decision starts. With a 325/275V / 6.3VCT / 5V transformer, you get a clear set of output voltages to compare against your circuit rather than a vague "it should work" part.
Quick verdict
This is a power transformer replacement for Fender part numbers 125P1B, 022772, and 66079B. It is listed at USD 68.95 in new condition. The high-voltage secondary is rated at 650/550 VCT at 100 mA, which gives you two B+ choices: 325V or 275V per side. If those core voltages line up with your Champ-family project, this transformer is a useful candidate.
Who it suits
The listed applications include versions of the Bronco Champ, Tweed 5F1 Champ, Princeton, Princeton Reverb, and Vibro Champ. If you are putting together one of those circuits, the dual B+ options let you build for a higher or lower plate supply without changing transformers. That is a practical advantage when you are still sorting out the filament and high-voltage needs.
What stands out
The two high-voltage options are the headline: 650/550 VCT at 100 mA means you can target 325V or 275V from the same product. The unit also has a center-tapped 6.3V filament at 2.25A and a 5V filament supply at 3A, so the heater and filament supplies are covered by the same transformer.
The primary is rated for 120V 60Hz. The mounting centers are 2.5" x 2", and the item height is 3 inches, so you have a concrete size reference when planning chassis placement.
Meaningful trade-offs
Because this transformer is specified for 120V 60Hz, your build's mains voltage needs to match that spec. The dual B+ options add flexibility, but the mounting centers and the item height still need to work with the chassis holes you actually have. The decision comes down to whether these exact voltages are what your circuit wants.
Product note
Transformer, Power, 325/275V / 6.3VCT / 5V, for Fender® Champ
This product is a power transformer replacement for Fender part numbers 125P1B, 022772, and 66079B. It is listed at USD 68.95 in new condition. The main reasons to choose it are the 325/275V high-voltage tap options, the 650/550 VCT secondary at 100 mA, and the separate 6.3V and 5V filament supplies. The limitation to keep in mind is the mains spec: the transformer is rated for 120V 60Hz, so a project using different mains voltage would need a different approach.
Bottom line
At USD 68.95, this 325/275V / 6.3VCT / 5V power transformer gives you a precise set of voltages to evaluate. If your Champ-family build needs two B+ options, a 120V 60Hz primary, and the 6.3V and 5V supplies in one package, it is worth a close look. If those voltages do not match your design, the listed price will not make it a fit.
