chriswhotakesphotos Posted May 23, 2016 Share Posted May 23, 2016 Hi, Klipsch forum! I upgraded amplifiers today, moving from an Adcom GFA-535 (65w) to an Adcom GFA-7607 (125w 7ch, but only used for 2ch). It's surprisingly good at two-channel for a home theater amp; it smoothed out the low end and took some sizzle out of high-volume listening, but it really takes a magnifying glass to AC noise. I've always had issues with noise; the source is my desktop PC, and it's incredibly pervasive. It happens wherever it's plugged in in the room and even generates some buzzing when it's off. Using a Furman SS6B power conditioner seemed to reduce it before, but it's not helping with the more powerful amp. Curiously, it seems that a lot of the noise is picked up by my preamp; it comes through regardless of how the volume pot is positioned, and cuts quite a bit when I turn the pre off. Since this low-end power conditioner doesn't seem to do the job, what should I be looking at? Thanks! Quote Link to comment Share on other sites More sharing options...
Matthews Posted May 23, 2016 Share Posted May 23, 2016 This is what I use. Richard Gray RGPC-600S on a dedicated circuit. Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
Chris A Posted May 23, 2016 Share Posted May 23, 2016 Since this low-end power conditioner doesn't seem to do the job, what should I be looking at? Thanks! Are you using more than one power outlet to power your preamp/amp? Do you use a television or screen in-room for viewing videos? If so, is that screen connected via copper cable? You've focused on power line noise but you haven't said anything about the proximity of the computer to the preamplifier and amplifier, etc. You mentioned that the computer will create noise even when it is off. Does the noise disappear when the computer is removed from the room? Chris 1 Quote Link to comment Share on other sites More sharing options...
chriswhotakesphotos Posted May 23, 2016 Author Share Posted May 23, 2016 I have the amp and preamp both plugged into the Furman strip, so they're both plugged into the same outlet. I use a computer monitor nearby; I assume the HDMI contains copper. The computer creates noise as long as it's plugged in. It even generates extra noise if one jiggles the power cable. I didn't consider the possibility of interference via proximity, but now that it's on my mind it seems to fit. It made just as much noise when I used a different outlet but left the computer in the same place. I've been planning to move the new amp since it generates a lot more heat than my old one and would clearly prefer more open placement, so perhaps I'll try simultaneously moving the computer farther away. Matt, I'd like one of those, but something about seeing those sexy tube amps in the background suggests it may not be in my range! 1 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 23, 2016 Share Posted May 23, 2016 I didn't consider the possibility of interference via proximity, but now that it's on my mind it seems to fit. The Furman should take care of anything on the grid. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted May 23, 2016 Share Posted May 23, 2016 This is what I use. Richard Gray RGPC-600S on a dedicated circuit. RG1 (Medium).jpg Matt ♪ ♫ ♪ This is the same one I been using for years!!! 1 Quote Link to comment Share on other sites More sharing options...
Matthews Posted May 23, 2016 Share Posted May 23, 2016 Matt, I'd like one of those, but something about seeing those sexy tube amps in the background suggests it may not be in my range! Chris it sounds like you may have other issues rather than dirty power. It can be a mind numbing process nailing down the exact cause. I would strongly suggest a dedicated circuit first. Move along to clean everything else up from there. A Richard Gray conditioner can be found for much less than you may think. The unit I have came strongly recommended by a fellow connoisseur. The link below is basically the same unit just with 2 less outlets and no fancy housing. If you keep your eyes peeled, a good deal pops up occasionally. The link below, IS a good deal IMO. http://www.ebay.com/itm/Richard-Grays-Power-Company-RGPC-400-Power-Conditioner-/291770807563?hash=item43eee5350b:g:vZwAAOSw9etXQgLT Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
Wolfbane Posted May 23, 2016 Share Posted May 23, 2016 I've been happily using an Opera Consonance D-Linear 15 for a couple of years. Details here: http://www.opera-consonance.com/products/accessory/D-linear15.htm Not cheap but less costly than the equipment I've got hooked up to it. Quote Link to comment Share on other sites More sharing options...
chriswhotakesphotos Posted May 24, 2016 Author Share Posted May 24, 2016 (edited) Matt, I might have to keep an eye out for something like that. It seems like the issue is indeed more complicated than I thought it might be: My full signal path is wall > computer > USB DAC (actually a DAC/headphone amp) > (power conditioner >) preamp > (same power conditioner >) amp. When I use my laptop on battery, it's dead quiet. Serene, even. When I plug my laptop in, however, there's that awful noise again. Curiously, it seems to only happen when the system reaches the wall in more than two spots (the preamp and pre being the first two). With my laptop plugged into the opposing wall and moved as far from the amp and preamp as it can get, plugging the DAC into the preamp creates the noise even with the preamp off, but unplugging the DAC from the pre and leaving everything else plugged in is just fine. The DAC's gain isn't a factor, either. What a predicament! I can even induce pops and sizzles by waggling different cables around when this happens. I could spend $250 on a decent used power conditioner. Maybe plugging the computer into its own power conditioner on another wall would help, too. Edited May 24, 2016 by chriswhotakesphotos Quote Link to comment Share on other sites More sharing options...
Matthews Posted May 24, 2016 Share Posted May 24, 2016 Chris, if possible any converter (i.e. 12V) plugs must me moved to a different circuit than your amps and conditioner are plugged into. This would be a good start at isolating the culprit. Quote Link to comment Share on other sites More sharing options...
chriswhotakesphotos Posted May 24, 2016 Author Share Posted May 24, 2016 (edited) As in converters from other countries' voltages? Don't have any of those! Further testing seems to point to dirty, dirty USB power. I know for a fact that my desktop has a noisy power supply, you can actually hear the same noise it generates through the speakers if you hold your head next to it. It's also a possibility that my laptop could be carrying some noise created by the aftermarket power brick. Surely enough, leaving my desktop PC plugged in as normal but out of the signal path creates almost no noise. (Its distinct power supply noise is still audible, but only with one's ear in the horn, which is never a good listening position!) There's still some background buzz that I'd like to stamp out, but at the very least, I've determined that the obnoxious noise I was hearing before seems to be coming over USB. Schiit makes a USB power conditioner that I think I'll start with as a solution. Edited May 24, 2016 by chriswhotakesphotos Quote Link to comment Share on other sites More sharing options...
Matthews Posted May 24, 2016 Share Posted May 24, 2016 Not converters like from other countries The power supply for you computer is a converter. For example a router or wireless transmitter would have a converter. As will any other devices of the like. Quote Link to comment Share on other sites More sharing options...
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