Question for amp experts about SPL Audio (Germany)

[TomJ]

SPL Audio (https://spl.audio/en/) designs and manufactures pro studio and consumer products in Germany. Their website describes the novel use of 120V (±60V) DC rail voltages in the gain stage of their consumer preamps and amps. They also appear to use a BJT cascode configuration in their amps. The build photos on their website show that every power transistor (onsemi MJL21193/4 BJT) is paired with an adjacent MJE15034/5 in the s1200 (4 pair/ch power transistors plus equal number of MJE15034/5) and also in the smaller s800 (1 pair/ch of MJL21193/4 plus MJE15034/5).

Can you please help me with two questions about this?
1) Are their claims accurate about the novelty and benefits of their 120V rail voltage in the gain stage?
2) Does the 185/285 watt output spec of the s800 surprise you with only one pair/ch of a power transistor that’s rated at 200w (16A cont, 30A peak)? Amps with one pair of power transistors per channel typically use devices with a higher rating (eg Pass XA25, Gamut). FWIW the output spec was confirmed on the bench in the German trade press.

thanks, Tom

 

[Doodski]

Quote >>> "With a power amplification of 2 x 285 W (4 Ω) [2 x 185 W (8 Ω)] or 1 x 450 W (8 Ω, Bridge Mode)"

If the amp power supply was not sagging under load then the power output with +/- 60VDC rails would be:
225WRMS @ 8R @ 7.5A peak.
450WRMS @ 4R @ 15A peak.

As the power supply is sagging a bit under load as is usual in most amps the rails would be @ the following values after sagging.
With 8R loads rails @ 54.4 VDC @ 6.8 A peak.
With 4R loads rails @ 47.7 VDC @ 11.9A peak.