Pete H Posted February 14, 2011 Share Posted February 14, 2011 What are the specs of your Carver amplifier? Did you get a chance to try the QSC with the RF-7s? The Carvers are rated at 120 into 8ohm and around 300 or 350 bridged if I remember correctly. I've run them bridged on the 7's for a while, but haven't run the 7's with the QSC as of today, but I will soon, I just have a lot going on right now and only got as far as bringing the QSC down and setting it on the shelf. Quote Link to comment Share on other sites More sharing options...
chuckears Posted February 15, 2011 Share Posted February 15, 2011 Finally had a chance to put the QSC-RMX2450 running my two home-built subs through its paces. I solved the fan noise issue by swapping it out with a quieter unit from Digikey - it isn't silent, but it is barely noticeable, much quieter than the central air running in my house. I put some small pieces of black tape over the power and signal lights, and they are no longer an issue. I also introduced the Samson S-Convert to the signal path between my Anthem Processor and the QSC, to bring the line level up to the professional level that the amp expects. I have been thus far been impressed with its effortless ability to keep up with everything I've thrown at it. I balance both subs independently at reference level, then when I run them both, it adds up to a gain of about 4 dB over reference, which I turn down to just 1 or 2 dB over reference; after viewing some very bass-heavy Blu-Rays (Pirates of the Caribbean, Iron Man II, Inception), I have been struck not only by the performance, but by how cool the unit runs. My Crown K1, which did not use a cooling fan, ran very hot after such material - I would swear that you could cook an egg on top of it after a vigorous sesssion. The QSC is barely above room temperature on the top of the enclosure, and never seems to break a sweat. This is hard to nail down, but I do notice a little tonal difference in the bass between the QSC and the Crown, as well; I would have to characterize it as a little more balanced with the upper range of bass I'm throwing at it (in the 50 - 70 Hz range); I was concerned at first that the Samson S-Convert was cutting off some of the very low content, below 20 Hz, and I was hearing the mid-bass more because of it, but a check of frequency sweeps running in increments between 5 Hz and 80 Hz indicates that I am not losing balance in the lowest frequencies. I view it as another splash of water on the frequently re-kindled "all amps sound the same" fire... I'm just surprised to notice it with a unit driving just the lower frequencies. I look forward to continuing my listening evaluations; a LOTR marathon is due, I think - I haven't had a chance to watch the entire trilogy on Blu-Ray yet... Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted February 15, 2011 Author Share Posted February 15, 2011 There is a $22 fan that is 12dB in the noise rating. I have now tried both and the $22 fan is not audible unless you put your ear up to the amp. I now have that fan on all 5 amps and the room is dead quiet!!! Enjoy. Quote Link to comment Share on other sites More sharing options...
stormin Posted February 15, 2011 Share Posted February 15, 2011 This is hard to nail down, but I do notice a little tonal difference in the bass between the QSC and the Crown, as well; I would have to characterize it as a little more balanced with the upper range of bass I'm throwing at it (in the 50 - 70 Hz range); I was concerned at first that the Samson S-Convert was cutting off some of the very low content, below 20 Hz, and I was hearing the mid-bass more because of it, but a check of frequency sweeps running in increments between 5 Hz and 80 Hz indicates that I am not losing balance in the lowest frequencies. I view it as another splash of water on the frequently re-kindled "all amps sound the same" fire... I'm just surprised to notice it with a unit driving just the lower frequencies. I would rather bet its because your running almost twice the power now. The Crown K2 has a lot more kick than the K1 as well. But yet again its a power thing. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 15, 2011 Share Posted February 15, 2011 There is a $22 fan that is 12dB in the noise rating. I have now tried both and the $22 fan is not audible unless you put your ear up to the amp. I now have that fan on all 5 amps and the room is dead quiet!!! Enjoy. So how much hotter are the internal parts running now? And how much shorter will your cap life be? Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted February 16, 2011 Author Share Posted February 16, 2011 So how much hotter are the internal parts running now? And how much shorter will your cap life be? DrWho, I have no way of measuring the internal parts. However, after a good 2.5 hour movie and an added two hours of music at near reference levels, the hottest temperature I measured coming out of any of the amps was 76 degrees F. I can't imagine any component is being stressed as they would be in a pro venue pushing thousands of watts. The mentioned fast have all been used and 'tested' by many others years before. In my application, the amps are in the room with me and the stock fan would make the amp unusable. I wish I had a closet or something to 'hide' the noise, but my room doesn't lend itself to that. Heck, some guys have just disabled the fan completely for home use and have not reported problems. I was not willing to go that far. I guess we will see how long they last. If they die due to heat stress, then I'll have to go to another fanless option. However, as good as my K1 was one amp made the room unfomfortably hot after a movie. The other issue with the K1 was the sleep circuit. Although I had lengthened mine to over a minute, it would occassionally cut out on quiet songs. The sleep circuit also became an issue when running Audyssey Pro. Edit: Just wanted to add some more temperature measurements after two action movies at reference level. Of my 5 amps, the hottest exhaust temperature was 86 degrees F which was 12 degrees above ambient room temperature. By comparrison, the exhaust temperature of my Sharp DLP projector was 118 degrees. I'm thinking for an amp designed for professional use, 86 degrees is a walk in the park. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 17, 2011 Share Posted February 17, 2011 Edit: Just wanted to add some more temperature measurements after two action movies at reference level. Of my 5 amps, the hottest exhaust temperature was 86 degrees F which was 12 degrees above ambient room temperature. By comparrison, the exhaust temperature of my Sharp DLP projector was 118 degrees. I'm thinking for an amp designed for professional use, 86 degrees is a walk in the park. Just keep in mind that when the air speed is slower, that the temperature gradients are larger and that AB amps don't need to be pushing full output to maximize their heating. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted February 17, 2011 Author Share Posted February 17, 2011 DrWho, thanks for the warning. I will certainly keep an eye on them. I have read probably 20 threads on the fan mod and only one reported overheating problems. I that case, it turned out to be a faulty amp and all was well after it was replaced. Of course, we are talking home use only here. Quote Link to comment Share on other sites More sharing options...
rick_m Posted March 2, 2011 Share Posted March 2, 2011 I too used a 12db fan to do the fan mod on a ep2000. The unit is very quiet now but still for sale! I prefer the sound out of my emotiva to power my klf-20's even though I have many friends that swear by Behringer mainly because they are affordable and powerful. As for a heat issue, never had a problem. After I did the fan mod I left the system on over night and very cool. However there was no load on the amp so the next morning I turned the gains to about half and jammed out for a few hours and once again, the amp was still quite cool mb just barely over ambient temp. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted January 8, 2012 Author Share Posted January 8, 2012 Decided to resurrect this thread to add two things. First, after a year of using the Behringer ep4000s in my system, they are going strong and performing very well, particularly with all my subs and bass bins. Second, I picked up a QSC PLX2 1804 for my HF section. It replaced the Hafler 3000 amp. First evening listening to it and am very impressed. The QSC PLX2 line recommended by CECAA850 is excellent. My horns are dead quiet with no music, no hiss, hum or other issue. Sound is crisp and clean. Imaging is excellent as it always has been with these horns. I think these pro amps are a great buy for home systems if you can integrate them successfully. I'll add that they run very cool with no problems with the quiet fan mods. I now have 6 amps with fans in my listening room and can't hear the fans. They are all mounted on an 8' pro rack. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 9, 2012 Share Posted January 9, 2012 Glad you liked it[Y]. It's almost like recomending a restaurant that you know is good. You really hope the person you recomend it to has the same experience that you did. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted January 9, 2012 Author Share Posted January 9, 2012 BTW, here are the innards of a recent build ep4000. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 9, 2012 Share Posted January 9, 2012 Dollar per watt, they're virtually unbeatable. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted January 11, 2012 Author Share Posted January 11, 2012 Here's a few watts for ya'! Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 11, 2012 Share Posted January 11, 2012 Awesome! What kind of service did you have to run to that (those?) receptacles? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 11, 2012 Share Posted January 11, 2012 I've got watt envy[:$] Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted January 11, 2012 Author Share Posted January 11, 2012 Awesome! What kind of service did you have to run to that (those?) receptacles? I ran three separate 20 amp lines that go directly to the main box. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted January 11, 2012 Author Share Posted January 11, 2012 I've got watt envy I love those QSCs now that you made me buy one.....all in good time. Quote Link to comment Share on other sites More sharing options...
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