The updated RCA to RCA box with step up conversion came from our 2022 update to the XLR to RCA box. This version allows for fixed gain of 1:2 meaning you can run your DAP with its 2V RMS out and get a real 4V out signal providing a robust input to most amps when a preamp isn't available.
This box is intended to take lower output sources and step them up/beef them up to provide more gain.
The RCA to RCA Black Box came from our use of input transformers on the test bench to isolate audio signals and minimize induced noise while testing. This same approach was used in Hifi’s golden era and has continued to be used in the Pro-Audio world.
This approach lowers noise floor and creates a common ground signal from the source to the amplifier improving the bass presentation, attack, balance, and depth. Midrange is improved with greater separation and depth. Transformers aid in the reduction of Sibilance and reduction of high-frequency hash. In short, this box will make your system quieter, and with improvements in the bass and midrange while reducing high-frequency hash/sibilance.