Pre/Power Amplifiers

Ordinarily when a stereo amplifier is bridged or BTL'd to supply twice the volts into a mono channel, power output increases into 8 and 4ohm loads but typically decreases into lower impedances due to a shortfall in current. Not so here for the Constellation Audio Mono 1.0 not only smashes its 400W/8ohm and 800W/4ohm specification with 590W and 990W (<1% THD), respectively, but it's also freed of the electronic protection that limited the Stereo's output to just 420W/1ohm [HFN Jul '15]. In practice then, under dynamic conditions the Mono 1.0 will sustain 690W, 1277W, 2165W and a full 2850W into 8, 4, 2 and 1ohm loads, respectively, for 10msec/<1% THD [see Graph 1, below]. With a 'clean' current reserve of over 53A, these monoblocks will drive any likely partnering speaker with ease.

Output impedance is a uniform 0.025-0.035ohm (20Hz-20kHz), increasing thereafter to 0.19ohm/100kHz, while the response into 8ohm is flat to –0.7dB/100kHz but (like the Stereo, but unlike the Centaur, HFN Jul '13] rolls away to –2.5dB/20Hz and –6dB/10Hz in the deep/subsonic bass. The 86.7dB A-wtd S/N (re. 0dBW) is some 5dB shy of the Stereo and distortion is very slightly higher, albeit following a more progressive trend from 0.00095%/1W to 0.0035%/10W, 0.033%/100W and 0.047% at the rated 400W/8ohm (all 1kHz). Versus frequency there is a marked difference between 'Balanced' mode, where THD is higher at low frequencies from 0.05%/5Hz to 0.007%/20Hz and 0.0038%/100Hz [see red trace, Graph 2] versus 'Direct' mode where THD is a 'flat' 0.0015-0.005% through bass and midrange black trace, Graph 2]. Both modes coalesce at 0.02%/20kHz and 0.06%/40kHz. See boxout, p59 for more on these options. PM