SuBXeRo Posted April 9, 2012 Share Posted April 9, 2012 Uggg. I biamped my 7s using the two extra channels on my outlaw 7125 and found that when the amp powers downs, the tweeters sqeals. The best way to describe the sound is it sounds like the caps are depleting. The tone starts off at about as loud as someone talking and reduces in amplitude until silet. I troubleshot the amp and removed the signal cables and left the speaker wires connected. Then i swapped the speaker wires on the speaker so that i could troubleshoot the different channels and the sqeal still exists only in the horns. This is soooooooooooooooooooooooo bizzare. Both speakers do it and it doesnt seem to matter what amp channels they are on. Ideas? Edit: I should add that the noise starts abouts 10-15 seconds after the amplifier has shut down Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 9, 2012 Share Posted April 9, 2012 Did you remove the straps between the binding posts? Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted April 10, 2012 Author Share Posted April 10, 2012 yep Quote Link to comment Share on other sites More sharing options...
elitedemo Posted April 10, 2012 Share Posted April 10, 2012 Ideas? Don't biamp [] Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted April 10, 2012 Author Share Posted April 10, 2012 i dont know what it is. i unbiamped tonight but this seems like a question for klipsch, ill have to give them a call tomorrow Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted April 10, 2012 Share Posted April 10, 2012 i unbiamped tonight but this seems like a question for klipsch, ill have to give them a call tomorrow Why Klipsch? Call Outlaw...it's their product that's responsible for the problem. The amp is going into oscillation because of the load. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted April 10, 2012 Share Posted April 10, 2012 Ideas? Don't biamp +1 are you really getting that significant of an improvement to make this worth your effort to troubleshoot? Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted April 11, 2012 Author Share Posted April 11, 2012 i unbiamped tonight but this seems like a question for klipsch, ill have to give them a call tomorrow Why Klipsch? Call Outlaw...it's their product that's responsible for the problem. The amp is going into oscillation because of the load. i already called outlaw about the issue. I am not thoroughly convinced its the amp. Only the tweeter section presents this noise. If i swap connections with the woofer section there is no noise at all. It could be that the sound is at a freqency that the woofers cant produce or are prevented from producing due to the crossover. I'll try biamping the rc-7 and see if it does it. I have 2 extra channels that i am not using and thats the reason why i wanted to biamp, to atleast give those channels some use. Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted April 11, 2012 Share Posted April 11, 2012 i already called outlaw about the issue. I am not thoroughly convinced its the amp. Only the tweeter section presents this noise. If i swap connections with the woofer section there is no noise at all. It could be that the sound is at a freqency that the woofers cant produce or are prevented from producing due to the crossover. I guess I didn't phrase things correctly.... The amp, is going into oscillation. Your diagnostic technique is flawed. Swap amps, not loads. Borrow a friend's, preferably a Rotel or a Krell, and try bi-amping with that instead. See if the noise persists. I doubt it will. A solution to your problem might be having to run a 2-4 ohm resistor in series with the horn section, then compensating for the attenuation in the pre-amp stage, to keep the 7125 out of its fun zone. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted April 11, 2012 Share Posted April 11, 2012 He is correct it is the capacitors in the amplifier that are discharging as you turn off the amp and causing the high frequency anomoly in the tweeters. No doubt the amp is causing it. Very little to gain using the same amplifier to biamp them since it shares the same power supply unless the amp is a true monoblock multiamp design. Quote Link to comment Share on other sites More sharing options...
SuBXeRo Posted April 11, 2012 Author Share Posted April 11, 2012 the amp is 4 ohm stable so the amp shouldnt be oscillating? The benefit of biamping is that each channel can drive 125w at 8 ohm and like 180w at 4ohm. Yes there is a single power supply but the amplifier channels are only limited by their capabilities vs the power out abilities of the psu. We aren't talking about a 20lb receiver, this is a 65lb power amp. I may never tap into the full power amount on a single channel let alone having them biamped but this is to ensure some better overhead than what i had before. My method of testing may be flawed overall but if the center doesnt squeal when biamped...what conclusion could you draw from there? I would say there is a design issue on the 7's. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted April 11, 2012 Share Posted April 11, 2012 Try a different electrical outlet on a different breaker Quote Link to comment Share on other sites More sharing options...
wstanger Posted April 11, 2012 Share Posted April 11, 2012 I have had 2 different pairs of RF-7's bi-amped(never could tell difference) and never had issues.It is not a design problem. Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted April 11, 2012 Share Posted April 11, 2012 My method of testing may be flawed overall but if the center doesnt squeal when biamped...what conclusion could you draw from there? I would say there is a design issue on the 7's. You've got a Marantz and a Harmon Kardon on premise, in addition to the Outlaw. Try running the top end of the RF-7 with either of those. Quote Link to comment Share on other sites More sharing options...
Fish Posted April 11, 2012 Share Posted April 11, 2012 I biamped my 7's long ago, made no difference, also no odd noise. The 7125 is a great amp, wth plenty power for 7 's, it does weigh about 50 lbs best I recall.The amp would be first suspect, good luck. Quote Link to comment Share on other sites More sharing options...
Greg Oshiro Posted April 11, 2012 Share Posted April 11, 2012 the amp is 4 ohm stable so the amp shouldnt be oscillating?<snip> <snip>the center doesnt squeal when biamped<snip> The amp is stable *with the amp turned on*. When the amp is turned off, the power supply capacitors discharge causing the power supply voltages to decay toward zero. The operating characteristics of the transistors/IC's change because of the lower supply voltages, causing the amp to be unstable. My rig has Crown D-75 amps and I hear faint squeals/pops/thumps upon shutdown. I don't worry about it because the level is low enough that I don't think any damage will occur. The load seems to be part of the problem since the center does *not* squeal. If someone can post a schematic of the RF-7 and the center channel speaker (RC-7?), I'll take a stab at a fix. There are amplifier circuit tricks that might remedy the problem (I've never seen a schematic for an Outlaw 7125), but it would probably be a major hack. Many amplifiers have output relays that disconnect the amplifier circuit from the speaker terminals when the amp is shut down. This avoids the squeal/thump/whatever problem, but then there are relay contacts in the signal path... the amp designer has to pick your poison. It's amazing what we can hear with high-sensitivity speakers! Quote Link to comment Share on other sites More sharing options...
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