Red Wine Audio Isabellina HPA LFP-V Edition Headphone Amp/DAC
Like all Red Wine electronics, the Isabellina HPA can be powered from an AC outlet, but its best performance is achieved when powered by its rechargeable battery. The LFP designation indicates a lithium iron phosphate battery, which offers many advantages over the more common sealed lead-acid battery, such as half the internal impedance, five times the number of charging cycles, no loss of cycle life from deep discharging, higher nominal voltage, flatter discharge curve, and higher energy density, which means it can be smaller and lighter. The sonic benefits are said to include greater dynamics, tighter and more resolved bass, and more open and extended treble response.
The battery pack includes a built-in, custom-designed circuit board that balances the individual battery cells, optimizing its performance and reliability. Also onboard is Red Wine's SMART (Seamless battery Monitoring and Auto Recharge circuiT) module that monitors the battery's voltage. If the voltage drops below a predetermined level, SMART automatically turns the unit off and starts recharging the battery, or you can choose to power the unit with AC while the battery is charging.
Another hallmark is the HPA's vacuum-tube stage, which uses a 6922 (E88CC) dual-triode to deliver more current gain than previous designs. This stage operates in pure class-A mode with increased input impedance and decreased output impedance and is said to deliver a more lifelike musical presentation with improved tone and harmonic richness and a taller, wider, deeper soundstage.
Not only is the Isabellina HPA LFP-V Edition a fine headphone amp, it also includes its own DAC that can be used to convert any of the three digital inputsTosLink, coax (BNC), and USBto analog for output from two RCA jacks. In fact, it can be configured with variable line-level outputs to act as a preamp for your digital sources. Interestingly, the DAC can accept digital signals up to 192kHz, but its resolution is limited to 16 bits with no oversampling. Company founder Vinnie Rossi admits that newer chips look better on paper, but he thinks most of them sound sterile and artificial in comparison.
With hand-assembled circuit boards, you'd probably expect the Isabellina HPA LFP-V Edition to be expensive, and you'd be right$2500 is a lot to pay for a headphone amp, even one that can also perform as a standalone DAC and digital preamp. But I have little doubt it's worth that much and even more. As Guttenberg wrote, "I've reviewed and auditioned a lot of headphone amplifiers over the years, but Red Wine Audio's Isabellina HPA LFP-V Edition stood out from the pack. The amp improved the sound of almost every headphone I used with it."