Measurements :
Dan D’Agostino Momentum monoblock power amplifier
Dan D’Agostino Progression Mono monoblock power amplifier
Parasound Halo JC 1 monoblock power amplifier
Pass Laboratories XA200.8 monoblock power amplifier
Jeff Rowland design 625 s2 stereo Power Amplifier
Look like the Jeff Rowland S/N ratio is better than Dan D’Agostino and Parasound
Dan D’Agostino Momentum monoblock power amplifier
The unweighted, wideband signal/noise ratio, ref. 2.83V into 8 ohms and taken with the input shorted, was a good 77.2dB, this improving to 78.1dB when the measurement was restricted to the audioband. Switching an A-weighting filter into circuit improved the S/N ratio to 81.65dB.Read more at https://www.stereophile.com/content/dan-dagostino-momentum-monoblock-power-amplifier-measurements#7q...
Dan D’Agostino Progression Mono monoblock power amplifier
Measured with the input shorted to ground, the Progression offered a wideband, unweighted signal/noise ratio of 57.5dB, ref. 1W into 8 ohms. This was primarily due to the presence of noise with a center frequency of 923kHz. Concerned that the amplifier was picking up some RF interference that was being demodulated, I turned off all the CFC and LED lights in my test lab, but the noise persisted. The ratio improved to 80.1dB when the measurement bandwidth was restricted to 22Hz–22kHz, and to 87dB when the reading was A-weighted.
Read more at https://www.stereophile.com/content/dan-dagostino-progression-mono-monoblock-power-amplifier-measure...
Parasound Halo JC 1 monoblock power amplifier
The JC 1’s unweighted, wideband signal/noise ratio (ref. 1W into 8 ohms) was good at 73.3dB, this improving to 87.8dB when the figure was A-weighted.
Read more at https://www.stereophile.com/content/parasound-halo-jc-1-monoblock-power-amplifier-measurements#upUeY...
Pass Laboratories XA200.8 monoblock power amplifier
The unweighted, wideband signal/noise ratio, ref. 1W into 8 ohms and taken with the input shorted to ground, was an excellent 83dB. This improved to 88.2dB when the measurement bandwidth was restricted to the audioband—and was even better, at 92.1dB, when the measurement was A-weighted.
Read more at https://www.stereophile.com/content/pass-laboratories-xa2008-monoblock-power-amplifier-measurements#...
Jeff Rowland design 625 s2 stereo Power Amplifier
the lab reporting figures of 80dB unweighted and 88dB A-weighted referenced to one watt.
Read more at https://i.nextmedia.com.au/Assets/20170221014711_jeff_rowland_685_s2_power_amplifier_review_test_lor...
Look like the Jeff Rowland S/N ratio is better than Dan D’Agostino and Parasound