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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.89b in hybrid memory play with pre-allocated RAM and AIFF files, hog mode and 24/176.4 NOS-style upsampling; Audirvana 1.4 in direct/integer mode, Metrum Hex, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2s
Preamp/Integrated: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X, TruLife Audio Athena, Bakoon AMP-11R
Amplifier: First Watt SIT1, FirstWatt SIT2, ModWright KWA100SE
Speakers: Aries Cerat Gladius, Boenicke Audio B10, Zu Druid V, Zu Submission, AudioSolutions Rhapsody 200, Aries Cerat Stentor [on review], soundkaos Wave 40 [on review]
Cables: Complete loom of Zu Audio Event, KingRex uArt USB cable
Stands: Artesania Esoteric double-wide 3-tier with TT glass shelf, Rajasthani solid hardwood console for amps
Powerline conditioning: 1 x GigaWatt PF2 on amps, 1 x GigaWatt PC-3 SE Evo on front-end components
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: £4.800
Tellurium Q have been around a few years plying the cable trade from the UK. As does any other hifi pub, we are on permanent drench of wiry solicits. To wear a rain coat through this fantastic flood of 'must hear, couldn't properly describe our amazing cable breakthrough in words', I use a basic filter.


Tell me what you're doing different to create your claimed amazing performance advantage. This eliminates 95% of petitioners.
Tellurium Q's PR man and director Geoff Merrigan had contacted me once before for their cables but maintained steadfast silence on their how and what. He then contacted me again still insistent that due to their preference for spending on R&D rather than defending their intellectual property in court, he couldn't talk about what they did. There was no backup for his very insistent stance that they had something new and genuinely different. Exactly what everyone else maintains. Really!

 

He finally asked whether he could interest me in their new class A single-ended transistor amp instead. That had just gotten Power Amp of the Year from HiFi World's editor Noel Keywood. If impressed, would I at least listen to their new speaker cable? I had to explain that I never 'just listen'. Accepting a product delivery equals a review. Unlike a punter with a return privilege, I don't try out and send back what doesn't pass. I'm fully committed either way. And it wasn't as though Tellurium Q hurt for reviews. Geoff's signature alone listed power cable of the year 2012, power amplifier of the year 2012, HIfi World products of the year 2012, HiFi News highly commended Jan 2010, HiFi + products of the year 2010, HiFi World cable of the year 2010, HiFi Choice 5 stars 2012 and Hifi World 5 globes August 2010, 2011 & 2012. For a newer company these accolades were quite the pile-on though specific to the green isle. I thus accepted the amp review offer but declined the cables which claim to eliminate phase distortion without explaining how and whose geometry for the speaker cables recalls DNM and Vovox.


Unlike cables which also often perform unpredictably from system to system, single-ended transistor amps are genuinely rare yet offer a thrilling alternative to their better-known triode brethren. In the right system they really can be the queen bee's bollocks. Doing a bit of due diligence with Hifi World's prior Iridium review, I learnt that the DC-coupled servo-controlled paralleled Mosfet amp "... produced just 18 watts into an 8Ω load which fell to 9 watts into a 4Ω load due to asymmetric output clipping suggesting that the low load under direct-coupled conditions was affecting the internal working point. This is why an output coupling capacitor is commonly used. Output impedance was very low, damping factor measuring an unusually high 93. DC output offset was a steady high but acceptable 60mV (6mV is common) on both channels into 4 and 8Ω loads.

"Distortion was low at all frequencies and outputs, with our analysis showing odd-order harmonics produced by peak distortion rather than crossover distortion as time-domain analysis showed. The spectrum remained fairly stable with level, a good sign, so subjectively it's unlikely the effect will be aurally obvious. The Iridium measured satisfactorily but must be used with sensitive loudspeakers requiring very little power. Overload will be obvious as clipping was hard. This is a very specialized amplifier with no obvious measurable benefits but SE Class As have an ardent following based entirely upon their sound quality, which is how the Iridium is best judged." Specs were given as 1.5Hz-60kHz response, 102dB separation, minus 90dB noise, 0.03% distortion and 1V input sensitivity.

"The monos got to the point of going out before our technical director discovered a tweak that will make them far better so we paused especially as the mini system is being revamped for Asia and the new integrated and pre are going full steam ahead along with more novel plug and cable developments. As a small company with resource limitations we really need to concentrate on the more commercially viable projects first and develop the niche stuff in the gaps left. The Iridium 20 was developed in some of those gaps. The monos will come when the gaps allow. Chassis are made, boards were made and sadly scrapped. As we are nearly there it will only take a small gap to finish up."


Having worked my way through the entire canon of FirstWatt amps except the Aleph J, I felt as prepped for low-power SETransistors as possible. I had in fact strategically sold off my remaining valve amp inventory to instead acquire the Nelson Pass SIT-1 monos. Those use a single silicon-carbide power Jfet output device exclusive to Pass which at his operating point exhibits true triode curves. They don't use feedback, degeneration or a driver stage. They're simpler and purer than even the most minimalist of tube equivalents. With 10 watts into 8Ω, they're just as application specific as a 300B SET however but offer considerably greater bandwidth and lower noise than nearly all of their valve competitors and none of their phase shift from miles of signal transformers. They don't exactly sound like triode amps but on balance and for my tastes offer a more compelling mix of virtues. Particular when preceded by a superior valve preamp, they had me give up on years of amusement matching power tubes to loudspeakers through output iron.  
Colin J. Wonfor, Tellurium Q's engineer