wuzzzer Posted January 4, 2007 Share Posted January 4, 2007 I noticed that this amp has XLR and 1/4" inputs. Is it difficult to get an adaptor that goes from RCA to 1/4"? Is there any degredation in sound by doing so? Do these amps have a good reputation? 300 watts x 2 (8 ohm), 500 watts x 2 (4 ohm), 800 watts x 2 (2 ohm). Distortion (SMPTE-IM) Less than 0.01% Distortion (Typical) 20 Hz-20 kHz: 10 dB below rated power 1.0 kHz and below: full rated power Less than 0.01% THDLess than 0.01% THD Frequency Response 20 Hz-20 kHz, +/- 0.2 dB / 8 Hz-50 kHz, +0, -3 dB Damping Factor Greater than 500 Input Impedance 6k ohms unbalanced, 12 k ohms balanced Input Clipping 10 Vrms (+22 dB) Cooling Variable-speed fan, rear-to-front air flow Connectors, each channel Input: 3-pin XLR & 1/4" TRS balancedOutput: Neutrik® Speakon® and touch-proof binding posts Amplifier Protection Full short circuit, open circuit, thermal, ultrasonic, and RF protectionStable into reactive or mismatched loads I can pick one up pretty cheap. I also still have my RF-7s that I have up for sale on craigslist but if the amp is good I'd be interested to see how they sounded with the QSC. Also would my HK be an ok pre-amp for this? Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 4, 2007 Share Posted January 4, 2007 I've been trying to get that amp or something like it for a while. How much are you paying and can you get another one [] seriously! the rca to 1/4 is available but there might be hiss as its going from unbalanced to balanced. DrWho said to get a 50 dollar soundboard and it will correct it. QSC has a great reputation. Heck klipsch uses the plx to power some of their equipment at indy and arkansas. Though the fan noise may be alot. Many people like deang love the qsc and how it sounds. The HK should be fine, that was what I was thinking too..... Now you are fighting dirty trying to beat me with your modded hk 3480 [] Quote Link to comment Share on other sites More sharing options...
gaspr Posted January 4, 2007 Share Posted January 4, 2007 I got Blue Jean Cables to make me a set of 1/4 to RCA cables to use from my Merlin to my Crown amp. Works great, no noise. Quote Link to comment Share on other sites More sharing options...
mas Posted January 4, 2007 Share Posted January 4, 2007 Simply changing connectors is not necessarily the solution. You may also need to match I/O sensitivities by changing from the consumer level to the pro-level I/O. A good example of a suitable unit is the Rolls MB15 ProMatch that converts consumer level stereo RCA signals to balanced XLR professional line levels. http://www.music123.com/Rolls-MB15--Promatch-i11845.music - Note: this link was built in Firefox and may not work - based on trying it umpteen times - and this site's editing tools are extremely squirrelly and definately not WSYWIG in the browser as well - oh well, you may just have to cut and paste the URL - sorry. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 4, 2007 Share Posted January 4, 2007 Really depends on the preamp as to whether you would need something such as was mentioned by MAS. Both my Classe solid state pre and my Peach tube pre run my QSC PLX 1202s fine without any additional equipment needed, pro to consumer. Some have reported some mismatches so that may not always be the case. I cannot really make sense of the various impedence figures, but those in the know in here have discussed it. I have used XLR to RCA adaptors (Cardis I think available at most guitar stores) with decent quality XLR cables. Work great with no additional hiss or noise. The stock fan is simply not that loud - even in my open rack. And even with two units running. Great sounding, inexpensive durable amps. Carl. P.S. I did run a QSC with RF-7s for awhile (with a tube pre) and the combo was excellent Quote Link to comment Share on other sites More sharing options...
Arky Posted January 4, 2007 Share Posted January 4, 2007 I have used H/K - QSC with rf-7's & it was excellent. I decided if I was going separates, I was going true separates. The QSC fan in my unit isn't noticable at any appreciable volume including video sources. My rack is open as well. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted January 4, 2007 Share Posted January 4, 2007 CJ, Can you use the Peach on HiZ mode or do you have to use LoZ mode with the QSC? Quote Link to comment Share on other sites More sharing options...
stormin Posted January 4, 2007 Share Posted January 4, 2007 Hey Wuzzer, I think you will enjoy the QSC to no end. I'm hooked on mine to be honest with you. Now I use an old Marantz 2325 as my pre which I absolutley love the 2325 as well. I imagine your HK will work fine as a pre. Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted January 4, 2007 Author Share Posted January 4, 2007 Cool, didn't expect to hear so many positive responses since I hadn't ever heard of the QSC brand name before. Now someone just needs to buy my RF-7s! [] Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 4, 2007 Share Posted January 4, 2007 CJ, Can you use the Peach on HiZ mode or do you have to use LoZ mode with the QSC? In my experience, you do not have to use the LoZ mode with the QSC (even though that is my favorite mode of the two). The HiZ mode does fine with the QSC, although I do not think you get nearly as dramatic a bass response with that mode. I do recall, however, someone who was less than fully pleased with a BBXtreme/QSC pairing, which is supposed to be the same mode as the HiZ in the Peach (Blueberry). If you plan on using the HiZ mode most of the time, you may want to find that thread. In there, Mark posted about the varying impedence matches, and some concluded that the BBX/QSC did not make for the best match that way. Of course, the HiZ mode in the Peach could be a difference impedence output than the Blueberry Xtreme, and you may want to shoot Mark an email on the subject. At least a QSC 1202 works for me with the HiZ mode of the Peach. A caveat is that the various QSC PLX models have different specs as far as impedence matching goes. While I can vouch for the 1202, one may want to review the various specs amongst the amps to see the difference. BTW, the 1202 (PLX 1 series) with 200 watts per is more than enough!! Carl. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 4, 2007 Share Posted January 4, 2007 Cool, didn't expect to hear so many positive responses since I hadn't ever heard of the QSC brand name before. Now someone just needs to buy my RF-7s! [] The reason is because the QSC is primarily a "pro amp" (even though there were some consumer models designed such as Stormin' has). "Pro amps" just do not get that much play (or even application usually) in the home stereo world, and these amps are usually used for DJs, bass rigs, and for PA systems. Respected in the pro arena, but usually not given much thought for home use. The fact that it has a fan turns off some people also. You may want to search some old threads in here. A number of prior threads about pro amps, QSC, and Crown, which are also some fine pro amps. Carl. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted January 4, 2007 Share Posted January 4, 2007 CJ, Are you using the XLR input (higher impedance) connections on the QSC? I had been looking at the PLX-1104 for some time, but never bought one. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 4, 2007 Share Posted January 4, 2007 CJ, Are you using the XLR input (higher impedance) connections on the QSC? I had been looking at the PLX-1104 for some time, but never bought one. Yes, rca/xlr adaptor from Peach output to XLR cable to XLR input on my QSC PLX. Carl. Quote Link to comment Share on other sites More sharing options...
ben. Posted January 5, 2007 Share Posted January 5, 2007 The level difference between pro (+4) and consumer (-10) nominal levels is actually more than 16dB as they are referenced to different voltages. Morley makes the Ebtech Line Level Shifters in 2 or 8 channels that can take care of the issue if it matters in your system.. Of course there are others, too. XLR or 1/4" TRS (tip-ring-sleeve) are typically LoZ at +4, 1/4" TS (tip-sleeve) or RCA HiZ at -10. The QSC manual would surely say. The PLX that end in 02 handle 2 ohm and the 04 handle 4 ohm. I'd go for the 02 for RF-7 without a doubt, regardless of power ratings. I've been sort of looking for one of the smaller 04 to use in a lightwieght bass rig with a tube pre, but they never seem to go much cheaper used than they are wholesale new. Folks like em. I'd trade a Crown I've got plus cash for one in a heartbeat. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 5, 2007 Share Posted January 5, 2007 Simply changing connectors is not necessarily the solution. You may also need to match I/O sensitivities by changing from the consumer level to the pro-level I/O. A good example of a suitable unit is the Rolls MB15 ProMatch that converts consumer level stereo RCA signals to balanced XLR professional line levels. http://www.music123.com/Rolls-MB15--Promatch-i11845.music I believe this one is cheaper: http://www.musiciansfriend.com/product/ART-CleanBOX-Two-Way-Stereo-Converter?sku=180613 Basically does the same thing. Quote Link to comment Share on other sites More sharing options...
Jay481985 Posted January 5, 2007 Share Posted January 5, 2007 both are the same price? Quote Link to comment Share on other sites More sharing options...
Rivendell61 Posted January 5, 2007 Share Posted January 5, 2007 Simply changing connectors is not necessarily the solution. You may also need to match I/O sensitivities by changing from the consumer level to the pro-level I/O. A good example of a suitable unit is the Rolls MB15 ProMatch that converts consumer level stereo RCA signals to balanced XLR professional line levels. http://www.music123.com/Rolls-MB15--Promatch-i11845.music I believe this one is cheaper: http://www.musiciansfriend.com/product/ART-CleanBOX-Two-Way-Stereo-Converter?sku=180613 Basically does the same thing. DrWho--I think we have been around this track before? Don't use those boxes. In home audio playback where signal integrity, quality, etc are paramount there is a better way to connect unbalanced to balanced: Create a balanced connection with a shielded twisted pair (ala Belden 1800). Have someone like Blue Jeans Cable wire it with XLR on one end (per QSC input) and an RCA on the other, with shield tied to ground at the RCA end. That's it. You will now have a balanced connection with improved noise rejection/CMRR over the unbalanced or the 'adaptor' method (which wastes the balanced input). Now, that will work in most situations (should always work but....there will always be an exception). The primary requirements are a correctly designed balanced input on the receiving amp, and a fairly low output impedance on the RCA end. And it is really the 'correct' way to go from unbalanced to balanced. Mark Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 5, 2007 Share Posted January 5, 2007 I do that all the time, but it rarely works with a low enough noise floor for the home - the only thing I haven't tried is that one resistor trick to create the impedance match, but it doesn't make up for the huge loss in gain. What's the point of having 200+ Watts available if you can only drive the amp to 20W? Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted January 5, 2007 Share Posted January 5, 2007 I added a low volume Panaflo fan to my QSC 1202 for abourt $20. Can't hear it at all, even with your ear up to it. If input impedance is a problem, a guy in Dennver can add a few resistors to make it act like a home amp. Check the basstalk forums. If your preamp has good output this is not an issue. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted January 5, 2007 Share Posted January 5, 2007 I noticed in the PLX2 range that the 1802 's output circuitry is AB, while the 2502 is 2-tier class H. What the difference and what is typically preferred? Also are rge PLX2 (second generation) that much better than the PLX (first generation) amps? Anyone know? Thanks inadvance. Quote Link to comment Share on other sites More sharing options...
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