The Iridium is a valve phonostage for moving magnet and high-output moving coil cartridges.
Valve phonostages from Rothwell aren’t new - the first one dates back to 1990 with pre-production prototypes going back to the 1980s. Remember, that was back when CD was a relatively new medium, most integrated amps and pre-amps still had on-board phonostages and the very idea of an out-board phonostage was pretty much unheard of. A valve outboard phonostage was very radical at the time and companies like Musical Fidelity or Cambridge Audio hadn’t even started making outboard phonostages. With a quarter of a century’s experience in phonostage design, the quality of the Iridium is assured.
The gain stages in the Iridium are built around ECC83 valves, chosen for their proven track record in small signal audio amplification and because they are widely available and easy to replace when required. RIAA equalisation is achieved passively with audiophile polypropylene capacitors and precision resistors, the valve heaters are powered by a regulated DC supply to eliminate low level hum, the HT supply is multi-filtered to eliminate ripple and separate left/right filters are used to minimise crosstalk and internal wiring uses solid-core silver-plated oxygen-free copper with PTFE insulation. No global feedback is used.
The cliche of valve “warmth” implies a distinct colouration which the Iridium simply doesn’t have. Instead the listener enjoys very finely revealed detail, a wide and deep soundstage and freedom from harshness at high frequencies. Dense recordings with many overdubs reveal all the individual parts with each instrument having room to breathe. The acoustics of the recording environment are also revealed, giving a satisfying sense of scale.