[Audiovista]

For an interesting industrial project we built a complex high voltage multiplier, and all connections needed to be verified. We took the Spark, bridged the outputs and connected it to the multiplier. A signal generator was connected to the inputs and we run 50kHz square wave, to get the output voltage of 80V peak to peak. The multiplier is a capacitive load, with many diodes which add a high degree of non-linearity, but the Spark was flawless. Zobel network started overheating after 30 minutes but that was not surprising, and we switched to sine wave to complete the pretest.

The next test will be with the massive high voltage transformer, as soon as the encapsulation cures. I thought that 50kHz, 80V pk-pk square looked very decent. The little fella knows how to handle itself 

[I.Greyhound Fan]

OK, when can I get a Spark to review

[Audiovista]

Unfortunately, the new Spark, MkIII did not make it to the States yet. We are ramping up production and our US partner, Verty Audio, is clearing the stock of the previous version, MkII (at great price, btw). When the new Spark gets stocked in the US, review samples will be available.

For the time being, we ship Spark MkIII directly from Europe, and Verty is providing full support.

[Audiovista]

Encouraged by the previous tests, we added a large home-made high voltage transformer to the mix. The bridging of the outputs was not needed and clean 50kHz square wave was fed to the very mixed load of inductive and capacitive components. We never anticipated that Spark will be used in such a challenging environment and ended up being very impressed 

The last image shows the Spark's output (transformer primary voltage, yellow) and transformer's secondary voltage (magenta), with effects of resonance (sinewave-looking parts of the waveform). The resonance happens between the transformer's leakage inductance and combination of the transformer's parasitic capacitance and multiplier capacitance.