The Grado Signature HP100 SE Open Air Headphone is a true audiophile reference headphone and as such it is not forgiving of source nor electronics, yet the musicality and presentation make for an absolutely pleasurable experience, in fact, the Grados seem to lend something to every genre of music whether it was Classical, Folk, Rock, Jazz, Lounge or even stark New Wave like The B⁵²s. I found myself racing through my playlist looking for new challenges, but felt it redundant to catalog every piece I heard as the experience was the same, massive soundstage, blistering speed, savage impact, epic dynamics, and luscious musicality. Like all Grado headphones in my experience, the HP100 SE is extremely efficient meaning though you want an amplifier of a sound quality commensurate with the Grados power is not an issue, in fact, you most likely will want something with a low gain option and a significantly low noise floor to take full advantage of them.

The Raal 1995 headphones aren’t your regular plug and play headphones, and in order for your amp to work correctly with the Immanis headphone you need to use one of Raal’s Ribbon Current Drive Interfaces like the TI-1b or their newest one (RCD-32(Ohm)) which you can see in the pictures. Both interfaces work fine, you don’t need to buy a new interface if you have one already. The RCD Interface, featuring purpose designed, highest-quality, toroidal transformers is designed in the style of a headphone stand. Toroidal transformers convert a voltage-controlled amplifier output into a current-controlled signal for driving the ribbons.

You also need to use a special headphone cable as well as an input Cable. You can buy a full bundle with everything you need, so no worries there. If you already have the cables and interface, then you can buy the Immanis only. Contrary to with the SR-1b you no longer may use the open-baffle Compensation Barrels. The barrels will change the intended sound signature but also, because of reducing the level above 2k for about 5dB, they may overload the ribbons with bass when you increase the volume to compensate for the 5dB loss. So make sure to remove the barrels from your SR-1a/b system when switching to the (Magna or) Immanis.

Let’s start with the basics of how an electrostatic driver (whether headphone or loudspeaker) operates. Imagine an incredibly thin and light diaphragm material (in STAX’s case, about 2 microns thick) that can accept a constant voltage charge. This wispy material is suspended between two electrodes which receive a fluctuating and alternating voltage charge from the incoming musical signal. This static charge (+) versus alternating charge (+ and -) condition causes the diaphragm to precisely vibrate, accurately recreating the music. The advantages are that in this type of system, the speed and accuracy of reproduction, along with the inherent transparency of output are just naturally very good. There are no magnets involved either, so any magnetically induced distortion (hysteresis) is nonexistent. The tradeoffs (if you factor easy portability out of the discussion) are mainly in bass capability. The driver’s surface area needs to be larger to reproduce lower frequencies and (even though they are close to your ears) they can only be so big when you wear them on your head