erikill Posted December 30, 2008 Share Posted December 30, 2008 I got a monoblock Parasound amplifier (HCA-1201A) for a holiday present, and decided to hook it up as soon as I got back. I tried plugged it into a seperate circuit than my tv, but strangely the amplifier turns itself on and produces feedback even without a RCA hooked up. Bad outlet I figured, I plugged the power line into the back of my power conditioner unit, and it still turned itself on, but no feedback now even without a RCA hooked up. I'd rather move it back to the seperate circuit, any suggestions on a filter to put in front of the amp? I am probably going to get an emotiva XPA-5, and want to make sure this seperate circuit is clean prior to hooking it up. Any other thoughts on what might be causing that much feedback over the power line? My house is around ~25 yrs old, so I figured it might just be age. Quote Link to comment Share on other sites More sharing options...
Dmannnnn Posted December 30, 2008 Share Posted December 30, 2008 but strangely the amplifier turns itself on Must be haunted. Your wording is confusing me. So the first try it had feedback without a source, just speakers hooked up? The second time there was not feedback without a source hooked up? Is it feed back or hum/buzz? Some of my outlets cause hum due to dimmers on low voltage lighting. Maybe you need another conditioner or perhaps there is a strong RF source close by? Quote Link to comment Share on other sites More sharing options...
Blvdre Posted December 30, 2008 Share Posted December 30, 2008 If it automatically turns itself on, it may be a hard switch that is shorted (always in the 'on' position). If it's a 'soft' switch (a momentary switch that triggers a circuit to switch on a power relay), you may have some failed circuitry. Quote Link to comment Share on other sites More sharing options...
erikill Posted December 31, 2008 Author Share Posted December 31, 2008 I should say its a huzz/ bum (I call it feedback) but it was coming through without the unbalanced source (RCA) attached. Going through the conditioner the hum/buzz was gone with no source hooked up. Both times the amp turned itself from standby with no source. It has a toggle switch that I leave it off when I'm not using it. But if i turn it on it immediately goes from standby (red led) to on (green). Not sure about the RF source close by, I think its just old wiring. Anyone have a recommendation on a wall conditioner or a something that won't mind me pushing amps off it? I can't deal with 5 channels of noise [:^)] Quote Link to comment Share on other sites More sharing options...
Dmannnnn Posted December 31, 2008 Share Posted December 31, 2008 It will go from standby to 'on' as soon as it stabilizes. This is normal. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted December 31, 2008 Share Posted December 31, 2008 Ground loop? Quote Link to comment Share on other sites More sharing options...
erikill Posted December 31, 2008 Author Share Posted December 31, 2008 Dman- Oh ok usually I've seen with amps that it stays on standby until it has a source. Do you usually turn it on vs / off? CEC- What do you mean by ground loop? I know my house is grounded outside to a nice piece of riebar. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted December 31, 2008 Share Posted December 31, 2008 A ground loop hum occurs when different components seeek different paths to ground. It's basically a 60 Hz hum. An easy way to tell if this is your issue is to get a cheater plug. It's a device that you plug your amp's 3 prong power cord into. They're just a couple bucks. The side that goes into the wall only has 2 prongs (no ground lug). If your noise goes away it was caused by a ground loop. If your amp has the issue in a wall socket but not when pluged into a power conditioner then this may be your problem. BTW, a cheater plug is not the fix, just a diagnostic tool. Quote Link to comment Share on other sites More sharing options...
Dmannnnn Posted December 31, 2008 Share Posted December 31, 2008 I'm not sure how much power these things use at idle, but I turn mine off anyway. I'll switch it on when I get home and let it warm up for awhile. The 1500 runs in class A up to something like 15 watts. I probably haven't driven it past 4 with the RF-7's. It gets mighty warm on top. Make sure there is plently of room for air to circulate. Don't put it on carpet or stack anything on top. There is a thermal protection system in most of these in case of overheating. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 1, 2009 Share Posted January 1, 2009 you are chasing a slippery snake...... I had a noise that occured when I had the pre-amp connected to the amp...the noise occured even if the pre-amp was off...as long as it was connected...the problem was a ground loop. but you say the noise is there even if nothing is connected to the inputs...and you say the noise is effected by the use of power strips/surge protectors. very strange indeed. Quote Link to comment Share on other sites More sharing options...
erikill Posted January 1, 2009 Author Share Posted January 1, 2009 I think I have one of those cheater plugs somewhere,if not I know Home Depot has one. It may have the ground loop hum, what are you suggestions on permanant fix, do they have good high current power conditioners, or do I need to build a line filter? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 2, 2009 Share Posted January 2, 2009 I know Furman has one that will handle 20 Amps. I'm sure there's others. Quote Link to comment Share on other sites More sharing options...
erikill Posted January 2, 2009 Author Share Posted January 2, 2009 I know Furman has one that will handle 20 Amps. I'm sure there's others. Thanks - this stuff looks better than the Monster I have (I'd think Monster is ok with all the digital equip). Would I be able to push both amps (xpa-5) through just one of these things? I guess the better fix also is to fix the ground leak. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 3, 2009 Share Posted January 3, 2009 Thanks - this stuff looks better than the Monster I have (I'd think Monster is ok with all the digital equip). Would I be able to push both amps (xpa-5) through just one of these things? I guess the better fix also is to fix the ground leak. I've got 4 300wpc (2 channels per amp) QSC amps on mine plus my display and players, with no problem. Quote Link to comment Share on other sites More sharing options...
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