- Written by Chris Heinonen
- Published on 05 December 2012
The Parasound Halo A 31 Power Amplifier On The Bench
When put onto the test bench, the A 31 performed up to its rated specifications on all the tests I could subject it to.
Rated at <0.2% THD+N, the A 31 outperformed that for both 4 ohm and 8 ohm loads. There was over 85dB of headroom on the tests, and no noticeable artifacts from any of the tests.
With 10 kHz there were artifacts at the odd and even fundamentals, though they were 75 or 85dB below the primary and outside of the audible spectrum. THD+N numbers were still well below the rated numbers from Parasound.
IM Distortion was specified at 0.04% but scored 0.03% or better on the testing. Looking to the sides of the 7 kHz tone you can’t see any artifacts and the noise floor is very low.
With 19 kHz and 20 kHz tones we see almost no artifacts on the 2V tests, but we do see some begin to develop on the 5V tests but they are still close to 90 dB below the main tones. There are small artifacts out in the non-audible spectrum as well, and a slow rise in the noise floor out to 95 kHz.
Looking at THD+N vs. Frequency, we see that THD+N stays right by 0.05% out until almost 50 kHz where it begins to rise.
From 10-22,000 Hz we see the frequency response is within 0.1dB all the way out.
Looking all the way out to 95 kHz we see there is a gradual roll-off in frequency response that accelerates around 60 kHz.
Overall the bench tests on the A 31 indicate very good objective performance, with no clearly visible flaws that would need to be addressed, and numbers that surpass their own specifications.