Although the Euforia comes on song inside of 15 minutes, the valves need a good 30-50 hours of playing to settle in. They run hot, too, so should you need to replace a valve, you need to give it a good 15 minutes without power for the valve to reach room temperature. As this gives time for the capacitors to discharge, this is a good idea for more than just preventing scorched fingers. However, Feliks Audio tacitly encourages a spot of tube-rolling, by giving you a list of usable substitutes. This is useful in two ways; you can play with the tonal balance to your heart’s content, and if the stock tubes blow and Feliks Audio is temporarily out of replacements, a pair of ECC32, and a pair of 6N5Ps can take the respective places of the driver and power tubes.
The Euforia is snug working with headphones with an impedance between 32Ω and 600Ω and includes a little rider in the English/Polish manual – “including planar magnetics.” Actually, what it should say is “especially planar magnetics” because the two go together brilliantly. Let me temper that… most headphones go well with the Euforia (Feliks say the Euforia is used with models like Audeze’s LCD2, BeyerDynamic’s T1, Focal’s Utopia, Sennheiser HD 800 and HD 800 S, and the ZMF Eikon), but the detail, dynamic range, and absence of background noise the Euforia brings to the table are extremely well suited to the properties inherent to planar magnetics. I used it both with my trusty-but-crusty HiFiMAN HE-500 and the Sennheiser HD 800 S (reviewed on page 14), as well as some more prosaic dynamic monitor-like/ENG designs from Audio Technica, Sennheiser, and Sony.
Those 50 hours pass slowly, because the Euforia gives you glimpses of what is soon to offer but coupled with a sense of veiling and dynamic limitation as the valves grow accustomed to their task in life. Then, the mists clear, and you are presented with… exactly the sound you heard when you heard good audio for the first time. It’s an ear-opening experience, with effortless dynamics, precise sounds within a focused – but not expansive – stereo soundstage (I preferred the Cross-Feed circuit in place), detailed, extended treble, deep, powerful bass, and exceptional ‘disappearing’ clarity to the midrange. Vocals in particular stand out for being just right sounding, and exceptionally articulate.
The amplifier has incredibly low colouration, with just a hint of richness and bloom at the lower end. With most of the headphones I played through the Euforia, this was only really noticeable on instruments like piano, making them sound even richer than they are in reality. On just one pair (the Audio Technica ATH-MSR7), the richness of the bass of the headphone plus the richness of the bass of the amplifier tipped the sound toward too dark a sound, but even here this balance was never less than attractive. On all other headphones I used with the Euforia, it just sounded like the real deal, just more enticing.
The Euforia exposes the lie that valve amplifiers have background noise. If anything, this amplifier is so low noise, it makes solid-state amps sound like they are laden with background hash.