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Lest you think the massive gold transformer cover pretentious as though housing really a number of parts to impress with faux endowment, stand corrected. It houses only the epoxy resin-potted 10kg/22lb double C-core output transformer. All the other iron bits (one big anode-voltage transformer, one smaller one for the 300B and ECC99 filaments, three toroidal filter chokes and the interstage transformer for 7 transformer/chokes per mono) reside in the black wooden chassis below deck. With such nuclear fire power behind the valves, the anode voltage is smartly delayed by 45 seconds. Phew!

During assembly - prior to wiring up the tube sockets and installing the anode power transformer


With the anode power transformer added

Sasa Cokic: "I already explained how the input and output stages are supplied separately by two different anode rectifiers. During the development phase, we tested many combinations of passive filters and our final circuit decision derived from extensive auditions. We use a standard CLC filter with a big choke for the 300B and an L-input CLC filter with two smaller chokes for the ECC99 driver. An L-input provides for a more stable anode voltage but won't properly operate below a fixed minimum current value. Our circuit has been designed to operate perfectly within the current window of what two halves of the ECC99 will deliver. The interstage transformer was critical because of DC current in its primary and because of the simple signal path of tube-transformer-tube-transformer which still remains complex to execute in many aspects. Finally, we concluded that the combination of stages was senior in importance to the internal design of each stage. That perhaps explains why our exploration into SE triode amplifiers will continue in the future. There are so many possible combinations to explore. Perhaps some day, a new audiophile generation will follow in our footsteps when we take our rest and perhaps they will find 'the ultimate tone' if we missed it."

fully wired up

If Sasa's comments (his name pronounces sasha) seem low-key and bereft of the self-congratulatory - er, exuberance one routinely encounters with paradigm shifty audio inventors full of breakthroughs these days, I'd agree. Quick to answer any technical questions I had, Sasa Cokic was overtly reluctant to make any performance claims other than that his team was satisfied with their work. All else was for me to sort out. As a reviewer, this clean division -- we make, you state what it amounts to -- was highly refreshing at this stage of the game.


Formal specifications include output power of 15 watts; input sensitivity of 2.5Vrms; 4/8-ohm outputs (others by request); 200VA anode power transformer; 500VA output transformer, 50VA toroidal filament transformer; frequency response of 10Hz (minus 0.2dB) to 110kHz (minus 3dB) and input impedance of 47K. S/N ratio is 72dB. THD is 0.35% at 1W/1kHz; 0.85% at 15W/1kHz; 1% at 1W/20kHz; 4% at 15W/50Hz; 5% at 15W/30Hz.

The designer's home system

Few maker of SETs dare give full-power distortion specs - and most assuredly avoid any mention of what happens at 30Hz under full throttle. That the Experience Reference is claimed to not exceed 5% in the worst-case scenario (full output in the bass) would be testament to good design indeed. Ditto for bandwidth. Many 300B amps struggle to reach 20kHz flat. Trafomatic maintains theirs is down 3dB at 110kHz. Naturally, the real test still awaited in the listening seat. I also had current-gen Western Electrics and EAT Diamonds and EML 5U4G meshies to roll and cover additional data points.