Audio Research amps - balanced & non

Of course there are transformers and there are transformers. Galvanic isolation is a good thing, as is balanced operation--both enabled by coupling transformers. But design & quality vary.

The Jensen transformers are excellent, and priced accordingly.

Twenty seven years ago I was, with my business partner, designing a head amp. At that time I had a meeting with a man named Dene Jensen at his facility. I spoke with him for about an hour. He was the first person to actually design a computer program to simulate various transformer designs and how they would react in a given circuit. The man was brilliant.He was in a wheelchair at the time and was not a well man. He made an impact on me. He was passionate about his research into transformer design and materials. After our meeting I was unconvinced that a transformer could work better than an active circuit for stepping up small signals. I was doing research on moving coil cartridge pre-pre amps, and was considering using his step up transformers. For use as an impedance matching device it is far easier to use a transformer. However, both Dene and I knew the inherent problems associated with transformers and frequency extremes for my application. Although his transformers were revolutionary for what they were capable of doing, you can't defy the laws of physics and frankly I wanted to design a very wide bandwidth device. The point is , in some applications transformers work extremely well. In others...not so well. Everything you do is going to be a compromise. Since there is no such thing as a straight wire with gain the only thing you can do is try it and see if it works. I did...it didn't work. Audio Research designed and sold a single ended to balanced converter that used an IC not a pair of transformers and that was their decision. Was it right or wrong? Who knows.

Hifigeek1... A step-up transformer, such as used with MC cartridges, is a lot different from a 1:1 transformer used for stage-to-stage coupling, which is what we are talking about here. A little circuit with an IC is a lot simpler and cheaper that a Jensen transformer, and no doubt was a good decision by AR. The one big advantage of the transformer is that it is passive...no power supply needed.