STAX only makes headphones, and they’re all supremely comfortable – these weigh just 295g plus cable, which is a brilliant ‘wearability’ enhancer. The SRS-4040 Signature package comprises SR-404 headphones (“earspeakers” in STAX speak) and the SRM-006t Driver Unit (amplifier). The latter’s champagne gold front panel boasts a dual-gang volume control, one power switch and two input selectors. Immediately underneath these are three five-pin ear speaker outputs, and round the back there are two pairs of RCA inputs, a ground, one pair of outs and one pair of XLR ins, plus the usual IEC power input. The SRM-006t features a Class A tube output stage (6FQ7/6CG7) working with a low noise dual FET input, the amplifier using pure balanced DC configuration. It gives 60dB of gain with 300V R.M.S. (1kHz) output voltage for the electrostatic panels of the earspeakers.
These don’t sound like any other headphones. There are clear reasons for this; electrostatic panels have lightning-fast response times (due to the lightness of the diaphragms), and the SR-404 earspeakers take great advantage of this. In a nutshell, these are one of the cleanest sounding headphones I’ve ever heard – they’re highly natural and precise but don’t confuse precision with dispassion. The package has an eerily clear insight into the music, as if a grimy window has been forced open to reveal the bright, brilliant sunlight outside. It is utterly addictive and compellingly enjoyable. All of a sudden, you’ve got this magical shortcut to your favourite recordings, and you start attacking your record or CD collection in earnest.
The brilliance of this STAX package is that despite the sharp relief it throws on the deficiencies of your power amp and loudspeakers (rendering them irrelevant at a stroke), it is never punishingly analytical. You never feel discomfort, or the sense that you’re listening to the music because you want to hear all that new detail. Rather, despite that incredible technical insight, you listen because you want to get into the music. Like the record label of the same name, the STAXes have soul. To my ears, you need to spend upwards of £10,000 to buy a power amp and speakers capable of similar musical insight. A unique and compelling product, no audiophile should be without it.