This piece is very well designed and has quite a powerful HPA at 10W, the same power as the L-10,000 OTL/OCL. All five outputs are active, and the unit has no issue driving amplifiers and simultaneously more than one headphone. Allnic states that all five outputs could be driven simultaneously; however, this is not recommended since it may impede optimal performance. It holds its ground against other Allnic linestages!
I have attached the manual for this amplifier with noted excerpts below that certainly apply to ALL tube equipment.
"Thank you for purchasing the HPA-10000 XL OTL/OCL Stereo Headphone Amplifier and Preamplifier. The HPA-10000 XL is a highly sophisticated but “purist” piece of audio technology. It is intended for experienced vacuum tube audio enthusiasts who understand and have the patience to appreciate the virtues of an innovative but “no bells and whistles” approach to circuit design and the superior sonic and “vintage” characteristics of New Old Stock (NOS) tubes - and who also value the exceptional private listening experience that the very highest quality headphones provide. The HPA-10000 XL is not a “plug, play and forget”, mass-market device aimed at headphone enthusiasts generally. Like all Allnic’s top-tier products, it is first and foremost a state-of-the-art example of “Tube Amp Done Right”. Proper care and attention, partnering with equally high-quality equipment, and following the guidance provided in this manual will facilitate confident, easy use and a listening experience of essentially unequalled quality for many, many years."
"Use of headphone cable adaptors is at owner’s sole risk. Issues and damage caused by ill-fitting cable adaptors are not covered by warranty. In addition, Allnic strongly recommends NOT using adaptors for headphone connections for reasons of sound quality: adaptors increase the number of connections and, therefore, resistance and distortion; and many adaptors may be of lower quality or different sonic character than your headphone cable and alter or diminish performance."
• DO NOT leave the HPA-10000 XL turned on for extended periods of time – NEVER 24/7, even for (an unnecessary) “break-in” period. This will greatly increase the likelihood of premature NOS tube failure. Power on the unit and let it warm up for some minutes; then, when finished a listening session, do a complete power off.
Final note: Placement of tube types other than those approved in this manual is at the owner's risk.
