Our Eddie Current listening lounge is where you can learn more about the enjoyment of the tube sound stage from Craig and enter into discussions with other Eddie Current owners about tubes, music, gear pairing–or a new IPA that goes perfect with an evening of listening!
To get things rolling (yes that’s tube humor!) I stepped away from my tech bench to answer:
I am often asked what the difference is between silver- and copper- based output transformers used in an audio device. The transformer is a key component to capture listening enjoyment and maximize the investment in your audio gear…
To lay down the foundation of what a transformer does, Wikipedia offers a good definition: https://en.wikipedia.org/wiki/Transformer
Copper vs. Silver Lining in Sound
While copper wire transformers are the most common and can reproduce the natural sound of analogue music, it has been tested and proven that silver wire delivers more micro detail with a sense of a larger, deeper sound stage. Silver wire need only be used in the secondary winding where the magnetic lines of flux are converted to music. Teflon coated stranded silver wire can actually measure with better high frequency response in the same design as solid copper wire without the bright or hard sound associated with silver speaker wire, or silver interconnects. Due to silver’s higher sensitivity to flux change (200%) it is able to reproduce lower level (micro detail) information. This results in an audible increase of the low level harmonics that exist in various musical instruments that can often disappear.
Silver Performance and Pricing
Recently the price of silver has increased to a point that the cost would be prohibitive for many to consider amps delivering the precious metal sound. Electra-Print Audio performed a test to see if the transformer secondary winding needed to be pure silver wire to achieve the sound difference. They determined that partial silver wire or silver plated multi-strand wire was found to be equal to using solid silver wire. The amount of silver needed is just 20% to achieve the improvement in the sound.
The Copper-Silver Golden Mix
You don’t need to sell your gold bullion to buy a great sounding amplifier! It has been proven that Partial Silver Stranded Secondary transformers work as well as solid silver wire output transformers. That’s because the flux generated by the primary voltage excites these surfaces first. The many strands then result in a larger silver surface area than one singular silver plated wire accomplishing the goal necessary for excellent sound reproduction.
The above observations are based on M6 laminations for the magnetic core. M6 is a tried and true magnetic material exhibiting good permeability and hysteresis. In the new Studio Junior amp a custom transformer has been designed that uses a combination of different core materials in a lamination sandwich. This along with a tertiary winding yields the benefits of silver at a fraction of the cost.