Just sharing a recent experience.
I have long been aware of the need to have a very “quiet” cable between the SUT and pre amp in my HiFi set up, but was rather surprised to find a background noise issue with the centre speaker when I recently switched my HT amplifiers around.
Switching a Parasound HCA1500 to bridge mode to power the centre produced an audible hiss from maybe a couple of meters away. I am not sure why. It is something I have never noticed before, but then I have never used the Parasound in bridge mode before either. I have to assume it had something to do with the fact the amplifier was bridged, which sounds a bit crazy! When operating in stereo mode, powering the fronts, there was no background hiss through the fronts at all with the amp. The mono powering the centre at that time didn’t generate any hiss either. The Parasound was in the same position on the rack when powering the centre and the fronts, so cable routing was very similar if not exactly identical. The only real difference I can think of being two interconnects and two sets of speaker cables in stereo mode and only one of each in mono. Why would that make any difference?
I tried various interconnects (Atlas Symmetrical, Atlas Asymmetrical, Audioquest, QED, XLO, Cable Talk, Mark Grant and some handmade Furukawa cables), all of them bar one produced different levels of hiss through the centre. The worst was the XLO, the best of the “noisy cables”, Atlas Symmetrical, Cable Talk and the Furukawa. The silent one was the Mark Grant HDX1. Fortunately, (or maybe because of), it was also the Mark Grant cable that gave the clearest audio.
It can’t be the signal coming from the amp, otherwise the hiss would still be there with the MG. I assume therefore, it must be the cables picking up interference, but why would being bridged make any difference? Or is there another explanation?
I have long been aware of the need to have a very “quiet” cable between the SUT and pre amp in my HiFi set up, but was rather surprised to find a background noise issue with the centre speaker when I recently switched my HT amplifiers around.
Switching a Parasound HCA1500 to bridge mode to power the centre produced an audible hiss from maybe a couple of meters away. I am not sure why. It is something I have never noticed before, but then I have never used the Parasound in bridge mode before either. I have to assume it had something to do with the fact the amplifier was bridged, which sounds a bit crazy! When operating in stereo mode, powering the fronts, there was no background hiss through the fronts at all with the amp. The mono powering the centre at that time didn’t generate any hiss either. The Parasound was in the same position on the rack when powering the centre and the fronts, so cable routing was very similar if not exactly identical. The only real difference I can think of being two interconnects and two sets of speaker cables in stereo mode and only one of each in mono. Why would that make any difference?
I tried various interconnects (Atlas Symmetrical, Atlas Asymmetrical, Audioquest, QED, XLO, Cable Talk, Mark Grant and some handmade Furukawa cables), all of them bar one produced different levels of hiss through the centre. The worst was the XLO, the best of the “noisy cables”, Atlas Symmetrical, Cable Talk and the Furukawa. The silent one was the Mark Grant HDX1. Fortunately, (or maybe because of), it was also the Mark Grant cable that gave the clearest audio.
It can’t be the signal coming from the amp, otherwise the hiss would still be there with the MG. I assume therefore, it must be the cables picking up interference, but why would being bridged make any difference? Or is there another explanation?