The Difference a Transformer can Make

Ernie Johnson writes:

“My brother Joe and I have been fans of old Vox amps for a long time. Not having the ‘spare’ money for one of the originals, Joe decided to build two amps… one for me and another for him.

The amp would have two discrete channels. One channel is a Marshallish 18 with a 6EU7 in the preamp and the other is a Voxish with an EF86 in the preamp with two EL84s in the shared output stage.

So… in August of last year the amps were finished. Not being in any real hurry and enjoying the process of tweaking and learning, we spent the last year fine-tuning the amps. It was fun having two identical amps so we could tweak one… then compare it to the other.

In the end the amps were not quite tonally where we wanted them to be. So… we began to question our transformer choices. The original transformer was obtained from a guitar/amp supply house that was supposed to be ‘THE’AC-15 transformer. (It’s the one on the left in the picture.)

Joe then found a transformer from another supplier that was a little stouter (second from the left in the picture) and installed it in one of the amps. There was a noticeable difference. This opened our eyes a little to the difference a transformer can make.

We started looking around and that’s when Joe and I talked with you, Paul [Patronete], and decided to try one of the AxiomVXO-15W-C transformers you suggested. The difference as I told you before was HUGE! After 2 months I am still astounded by how much better the transformer sounds. Magic, 3D, supercharged, bigger, sweeter, dynamic….

The story doesn’t stop there. Wondering if the big sonic difference was due to the physical size of the transformer—after all the AxiomVXO-15W-C is HUGE compared to the previous transformers we tried—we decided to do one more experiment. We had access to another transformer similar in size and specs to the AxiomVXO-15W-C and installed it in the other amp (third from the left in the picture). NOPE… not the same at all. The other transformer was an improvement over the first two we tried… but it’s still not close to the . The has a much bigger low end, sweeter mids and highs, and somehow that thing I keep calling ‘3-D’ that makes the sound hugely vibrant!

Paul, I know none of this is news to you. I wish we had called you BEFORE we began to build the amps. Your knowledge would have saved us some time!! (Perhaps if we had begun with a , our tweaking process would have been much shorter!) Forgive me for dragging on but I just wanted to again thank you for your advice, and time and caring enough to share your experience with us… and thanks for making the transformers!

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