ToneQuest: Transformers 101

Hey, you guitar players… don’t think for a minute that you should skip the following articles because they are too technical. You’ve dropped some big money over the years on your guitars and amps, right? Transformers are the very heart of every amplifier, and your output transformer can influence your tone every bit as much as your choice of pickups, tubes, and speakers. Our attention was recently focused on output transformers after one of our all-time favorite “keeper” amps, a blackface Fender Pro Reverb with an amazing pair of Jensen Vibranto speakers went down with a bad output transformer. (By the way, Pro Reverbs remain some of the best vintage bargain tone machines every made, and why they have failed to receive the high praise and prices reserved for blackface Super and Deluxe Reverb amps is mystifying. Get yours now.) Cesar Diaz kindly sent us a new Mojo Tone replacement OT, and it was immediately apparent to us that although we had always considered the tone of our Pro to be extraordinarily good, things had improved significantly after installing the new OT. The amp had more punch and power with less sag, and that got us wondering if output transformers could slowly decay over time, subtly sapping the full potential of a great amp. We concluded that it can, which led us to consult with a couple of experts on the topic of guitar amplifiers and transformers. We asked Victoria Amplifier founder Mark Baier (aka Sam Bisbee) to comment on his experiences with OTs, along with the premier builder of custom amplifier transformers on the planet, Sergio Hamernik of Mercury Magnetics. Sergio has been blueprinting exceptional vintage examples of the great transformers of the past and supplying discerning guitarists and their technicians with accurate reproductions that succeed in delivering authentic vintage tone. Stay tuned for reviews.

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