"After many years of trials and improvements, we arrived at a layout of electronic and mechanical parts which netted the shortest possible signal path, high resistance to interference, excellent cooling and thermal stability. One of the unique solutions is our HPCS or Harmonics and Phase Conversion System. It uses Jfets which thanks to precise parts selection generate even harmonics whilst inverting signal phase. HPCS introduces subtle modifications to the harmonic spectrum and dynamics of the signal which adapts the DM-250 to the subjective needs and characteristics of human hearing. This resembles to a certain extent the effects obtained from tube amplifiers just without the inconvenience of using tubes."

Also, "in addition, the amplifier precisely amplifies the signal throughout the entire acoustic spectrum with perfect dynamic bass. The enhancement of medium and high frequencies with negligible phase shift allows the listener to hear the exact location of apparent sound sources and the effect of the depth planes in the soundstage. Thanks to this, it is possible to obtain a holographic soundfield far beyond the classical effects of stereophony. The phono stage uses RIAA correction via TI opamp based on Jfets. The RIAA curve was modified with an additional time constant of 3.2µs (Neumann) to obtain greater spatiality of the musical image." So we have a versatile device in a relatively small elegant chassis with interesting front and lovely round metal remote. High power should work with virtually any loudspeakers. As a result, users may base their choice of speakers exclusively on sonic preferences.

For this test I paired the DM-250 with my two resident speakers. One is the 3-way sealed Ubiq Audio Model One Duelund Edition, the other an interesting high-sensitivity line source in an aluminium enclosure called Mach4 from GrandiNote. The last part of the test saw the impressive €50'000+ Soundspace Systems Pirol speaker with active bass under review. Here the Struss fed low-level signal to its woofers via the pre-out and only drove the midranges and tweeters.

Using my two very different speaker residents turned out to be extremely interesting. With each, the amplifier sounded different or better, different was what I heard from the speakers. It seemed as if the Struss highlighted their respective characteristics without altering them in any particular way. After listening to the Mach4, I noted that the DM-250 sounded fast, dynamic, delivered quite impressive bass which didn't extend very deep but was very nicely differentiated and tuneful while the resolution and saturation of the midrange and top band were very good. I was also impressed by how pure and tonally neutral the presentation was without becoming too bright or excessively analytical.