Are you familiar with tube hiss? That would be my first guess. Your linestage has tubes, have you checked them?
Got Noise?
OK Guys, need your help with this one. Recently I've noticed a fairly high degree of background noise (sounds like a "ffffsss" coming through my system at idle. The noise is only audible when the amp is turned on, not any of the other components. The amp has been tested by the manufacturer and he reports no issues. (Amp is a Modwright KWA150 and I asked Dan to check this for me when he did the "SE" upgrade a month or so ago). The level of noise is audible when I am playing music only at very low volumes, which has been the case over the past 4 months since we now have a baby on board. In fact, it is possible that nothing has changed but the simple fact that before the baby I was listening at higher volumes and did not notice the background noise. On the other hand, it is somewhat intrusive and if there is something going on elsewhere then I'd like to address it. FYI I have a 20 amp dedicated line to my system and have an Environmental Potentials 2050 surge suppressor/noise cancelling device installed on the panel, which I had my electrician confirm has been correctly hooked up. Is it possible that something is happening at the pole where I have a transformer shared by two other neighbors? I can't decide whether this is a new problem that has developed or simply an old problem that I did not know was there until I started listening at much lower levels in the past few months. Tell me, when your system is at idle how much noise do you hear when you put your ear to the drivers? Or from your listening position?
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- 14 posts total
Hi Mark, If you can hear hiss at the listening position while music is playing at any volume, something is definitely wrong. Notwithstanding the fact that the high sensitivity of your Daedalus speakers will reproduce any noise that is generated or introduced downstream of the volume control to higher levels than would result with less sensitive speakers. With my preamp muted, the hiss level from my Ulysses is almost imperceptible with my ear less than two inches from the tweeters. I do have a very slight ground loop-related hum, though. Some thoughts and questions: 1)My guess is that the problem is unrelated to AC power quality. 2)Have you tried both positions of the "Gnd" switch on the back of the amplifier? N.B.: To prevent the possibility of loud transients, I would strongly suggest not changing the position of that switch while the amp is on, and waiting a minute or so after turning the amp off before changing its position. 3)What happens to the noise level if the preamp is turned on but is muted? 4)Are your interconnects between preamp and power amp shielded or unshielded, and balanced or unbalanced? Shielded and balanced would provide the best noise rejection. If that is not what you have, you might want to try some inexpensive Mogami Gold Studio cables, which are known for their excellent noise rejection. 5)If they are not already, route the interconnects with as much separation as possible from power cords or other possible sources of electrical noise. 6)Good suggestion by Mofi about disconnecting everything but the amp. For the results to be totally conclusive, though, you should put shorting plugs such as these on the amp inputs. Hope that helps. Best regards, -- Al |
- 14 posts total