Audiologica Ltd: Company Registration Number : 6632457    VAT Registration Number: 892 5261 02

Headphone impedance range: 8 to 2,000 Ohms / 16 to 600 Ohms preferred

Power output: (rms, both channels fully driven at 1% THD)

32 Ohms: 140mW/channel; 600 Ohms: 30mW/channel

Input sensitivity (for specified power output into 32 Ohms): 511mV rms

Input impedance: 37k Ohms at max volume; 50k Ohms at min volume

Distortion: (THD plus noise at 9 o'clock volume control setting (qtr power))

10Hz-20kHz: better than 0.04%; 10Hz-1kHz: better than 0.02%

Frequency response (±0,-3dB) 10Hz - 35kHz

Output noise: (22Hz-22kHz, quasi-peak/un-weighted) -78dB

Channel balance: better than 1dB

Crosstalk: Left to Right -56dB; Input to Input -68dB

Input selector centre-off position: non-shorting; -38dB at max volume with 2V rms input (ref: 1kHz and 10kHz)

Output Stage: Bipolar class AB

Supply voltage: 24V DC unipolar

Size: (approx.) W: 107 x H: 50 x D: 185 (mm) inc. controls

The Solo Ultra Linear headphone amplifier lets the music flow. When the band throws everything into the mix the Solo Ultra Linear headphone amplifier doesn't lose the plot. At last a headphone amp that does away with the sharp glaring edginess so common in today's headphone amps. It replaces it with all the music - all its scale: however you like to describe real music the Solo Ultra Linear headphone amplifier does it that way!

So what's the Solo Ultra Linear secret? Well, there are many, but for one its distortion is quite unlike any other solid state headphone amp: solid state distortion increases in proportion to frequency, so when there's lots of highs the distortion increases and that's highly noticeable playing complex music. The distortion from the Solo Ultra Linear remains consistently low throughout the audio spectrum. Why? Because its bandwidth is exceptionally wide before the application of a thing called negative feedback. Solid state headphone amps use negative feedback as a fix for distortion as well as noise but also to widen the bandwidth, but all it succeeds in doing is adding glare. The highs also affect the sound at bass and mid frequencies because the leading edge of a note is fast - if the highs are distorted much of the fine detailing in the bass and mid frequencies is lost. Also by improving on distortion linearly throughout the entire audio band the sound stage comes alive as you've never had before.

Another one of the Solo Ultra Linear secrets is its greater input linearity: usually a solid state amp cannot take much input signal before it is overdriven when it distorts badly and copious amounts of negative feedback have to be applied to correct it. What you end up with is restructured music that doesn't quite hit the spot.

Like most headphone amps except for the ridiculously expensive, the Solo Ultra Linear is basically a pair of transistor assisted op-amps. But here we chose one of the very few op-amps which feature one of the best output stages ever designed! Featured in Wireless World in 1969 and authored by J L Linsley Hood it remains the most musical of output stages and is class-A. To these we add our proprietary open-loop bandwidth widening technique and the difference is staggering.