One of the handful of Staxs portable electrostatic amplifiers, the SRD-X Pro is not an energizer-type solution, but a transformer-based one, with a small low-power speaker amp inside that can run off of 8 C batteries as well as a 12V wall adapter. Due to this being a transformer as opposed to an energizer, the sound quality on this unit is absolutely superb for something that can be used away from home, but it is heavy, especially when loaded up with batteries. This unit can also support one pro bias and one normal bias headphone at the same time, if you really wanted to. This amplifier has one set of RCA jacks for input. I have included both the stock (Japanese 100V) Stax wall adapter that this amplifier ships with, as well as an upgraded universal one that has a much higher current rating and lower noise. Please note that using the Japanese wallwart in the US without a 120V to 100V step-down transformer will cause permament damage to both the amplifier and the headphones. This unit is in great cosmetic condition, with only a couple scratches on the left side. It has the original battery cover, and works perfectly. It has not been serviced. Will ship via USPS PriorityMail with tracking and insurance.

One of the handful of Staxs portable electrostatic amplifiers, the SRD-X Pro is not an energizer-type solution, but a transformer-based one, with a small low-power speaker amp inside that can run off of 8 C batteries as well as a 12V wall adapter. Due to this being a transformer as opposed to an energizer, the sound quality on this unit is absolutely superb for something that can be used away from home, but it is heavy, especially when loaded up with batteries. This unit can also support one pro bias and one normal bias headphone at the same time, if you really wanted to. This amplifier has one set of RCA jacks for input. I have included both the stock (Japanese 100V) Stax wall adapter that this amplifier ships with, as well as an upgraded universal one that has a much higher current rating and lower noise. Please note that using the Japanese wallwart in the US without a 120V to 100V step-down transformer will cause permament damage to both the amplifier and the headphones. This unit is in great cosmetic condition, with only a couple scratches on the left side. It has the original battery cover, and works perfectly. It has not been serviced. Will ship via USPS PriorityMail with tracking and insurance.