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New member Username: MrafkaLexington, VA United States Post Number: 1 Registered: Sep-11 | Hello, I'm a total noob, so my question might seem silly. Anyway, I got a a really powerful (1300 watt) amplifier, and it has two TRS inputs labeled Ch1 and Ch2. Now, I want to connect it to my ipod. What sort of cable should I use between the ipod and the amp. I have a 3.5mm stereo to Dual 1/4" mono (TS) Y cable. Would that work? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16694 Registered: May-04 | . If the plugs fit the jacks, it should work. |
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New member Username: MrafkaLexington, VA United States Post Number: 2 Registered: Sep-11 | Well, the amp has two 1/4" inputs labeled Ch1 and Ch2 and it says 'Tip-negative, Ring-Positive, Sleeve-Ground' underneath. So I should be good plugging TS jacks in TRS inputs? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16705 Registered: May-04 | . You've not mentioned what equipment you're trying to connect up to. I'm always a little confounded that most posters expect other people to read their minds and know things which might be relevant to the discussion. The answer to your question is most likely to come from the manufacturer which will know the particulars of their equipment designs. Tip/ring/sleeve connectors can be several different things depending upon how the equipment is designed. In most conventional home/consumer audio gear tip/ring/sleeve would indicate a stereo plug - two channels of information existing on the tip and ring with the sleeve acting as ground for one single plug/jack. If you plug a "mono" or tip/sleeve plug into a jack expecting a TRS plug, you'll do no damage. The second channel information which would ride on the ring just won't exist since there are no connections being made to that portion of the plug. The title of your thread indicates "balance vs unbalanced" lines. What makes you think the amplifier is expecting a balanced input plug? Balanced lines in consumer home audio would typically be accomplished through the use of XLR's, not 1/4" plugs. A "really powerful (1300 watt) amplifier" sounds to me like this might be car gear. If so, I have no idea what car gear might have put together and, since you've not helped me out with information, I can't tell you what to plug in where when I'm asked to assume equipment I know nothing about - not even a model number or manufacturer. I don't know what "the amp has two 1/4" inputs labeled Ch1 and Ch2" means in the lingo of the manufacturer. If the amp was assembled in China, it could mean just about anything. CH1 and CH2 would typically mean left and right channels. But I have no idea where your idea of balanced vs unbalanced came from or what the manufacturer expects to have as connnections. And your posts haven't given me anything to work with. Try this; 1) look through the owner's manual for information. 2) Try calling the retailer who sold you this equipment. 3) Contact the manufacturer for more advice. I can't work in a vacuum. . |
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New member Username: MrafkaLexington, VA United States Post Number: 3 Registered: Sep-11 | Hey, Thanks for the long answer. It is an old QSC USA1300 power amp, no car audio. The manual can be found here http://www.manualnguide.com/dl/25574/ Ok, so I tried to simplify the question, here's the full story. I know for a fact the amp used to work, but then I moved and lost the cables that went with it. Now, I tried with the cable I was talking about and nothing is coming out, so I was trying to figure out whether it's the wrong cable that I'm using or the amp is broken (which is likely too). I'm feeding the output into MTX PWR215 speakers. http://archive.mtx.com/proaudio/pwrSeries.cfm Thanks |
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Bronze Member Username: KevinwhitePost Number: 28 Registered: Aug-11 | Well, have you made sure that iPod can be connected to it? As far as i know, if the amplifier's rated power is too large, you can not connect it to your music players like iPod. or iPod will break down with the high electricity. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16713 Registered: May-04 | . "As far as i know, if the amplifier's rated power is too large, you can not connect it to your music players like iPod. or iPod will break down with the high electricity." Don't know where or from whom you obtained that information but, no, the output wattage of the amplifier has nothing to do with the type of input source/player you can use. And the wattage out cannot harm the input device unless there would be a very unlikely catastrophic incident such as a humongous lightning strike which would enter the amplifier through the AC line and vurtually melt the amp into a giant glob thus fusing the input connectors to the amp. Such an incident would likely destroy all life within a few miles of the srike and your problems would be more severe than your iPod not working. The input source is safe from anything the amplifier can do. The reverse is not true. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16714 Registered: May-04 | . "I know for a fact the amp used to work ... " Yeah, I know alot of things that "used to work" but they don't now. First, check the speakers for operation. Are you certain they work? How do you know? Next, check the amp again. First, there would appear to be two gain controls on the amp above the 1/4" jacks. I can't tell from the manual because they've grayed that area. But, if there are gain controls, make certain they are not turned down to "0". Raise them to about a "7 O'Clock" position. If the gain controls aren't the problem, check the external fuse. If the front power LED doesn't light up, pull the fuse holder out of the back of the amp when it is powered down and unplugged. A visual check of the fuse oftentimes won't tell you whether the fuse is blown. Replace the fuse or have it checked with a continuity meter. You can buy a cheap checker for a few dollars at any electronics or home improvement type store. Do not replace the fuse with any value other than what came out of the amp or what is specified by the manufacturer. Inserting a different fuse value can turn the amp into a fire hazard. The 1/4" jacks on the amp - or, more specifically, the 1/4" plugs you are using - are the likely problem. The ring is where the amp expects to pick up its "hot" signal lead. With a typical mono 1/4" plug the tip is the "+" connection. What the amp is getting from the mono plug you have is a ground and a neutral/negative, there is no hot or "+" connection with the two section mono plug. Therefore, no sound. If the amp had a provision to run as either balanced or unbalanced, it would normally operate as I described above with the tip being hot and the sleeve as ground when set to "unbalanced". QSC has decided they should build an "inverting" balanced line amplifier and they have reversed the typical orientation of their input connections. You're going to have to deal with this either by building cables specific to the QSC or buying cables meant for this plug/jack orientation. I'm going to guess you are not adept at soldering plugs, right? If the mono plugs are the problem - and I very much suspect they are, you're going to have to make up the correct cables/plugs or buy a set of cables which will properly terminate the iPod. Your best bet is a pro audio shop since the staff at Radio Shack know cell phones but no longer know audio. Call a local pro sound/sound reinforcement/commercial sound shop and explain to them the cable/plug type you need - a 3.5mm stereo male plug split to two male 1/4" TRS plugs with the ring wired as hot. A QSC dealer is your best bet but any shop which supplies any of the three types of sound systems I mentioned in the last sentence should be able to provide some assistance. I have my doubts you'll find such a set up since iPods and QSC/high wattage sound reinforcement amps aren't commonly paired together. But you might as well try, maybe they can solder something for you that would work. If nothing else, call QSC customer service and order the right cables. If you end up going to the pro audio shop, take the amp along and politely ask them - on a quiet afternoon when they aren't packed with customers - to just check the amp to make certain it is currently operational before you go any further down this road. . |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16716 Registered: May-04 | . If you buy or have cables made specifically for the QSC, label them as such since most other amplifiers would expect a more conventional TRS connection scheme. |
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New member Username: MrafkaLexington, VA United States Post Number: 4 Registered: Sep-11 | Ok, I understand now. Thank you for your extensive answers. I do know how to solder, I've soldered components to circuit boards before. Yeah, the speakers are OK, because I've checked them with another amplier. I think I will be fine making the cable myself, but can you just go through what I should connect with what. My guess is (say 3.5mm is A and 1/4" are B1 and B2) tip A -> ring B1, ring A - >ring B2, sleeve A -> sleeve B1,B2? Is that right? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16717 Registered: May-04 | . Yes, basically what you have is correct. The tip on the stereo 3.5mm plug is hot (+) right channel. The ring on the mini plug is hot (+) for the left channel. The sleeve of the mini plug is ground (which shares the duty of neutral (-) in an unbalanced line). The tip (+) of the 3.5 goes to the ring (+) of one 1/4". The ring (+) of the 3.5 goes to the ring (+) of the other 1/4" plug. The sleeve (-) of the 3.5 goes to the sleeve (-) of both 1/4" plugs. The tip of each 1/4" plug shouldn't need any connection. The balanced QSC might object to not having a neutral signal flow - but I doubt it. If you connect the cables as suggested and still have no sound, jumper from the sleeve of each 1/4" plug to the tip of that same 1/4" plug and that should make the connection complete. QSC has some funky circuits that might try to protect the amp from an unbalanced line and this might not work at all. I suspect it will but, most balanced lines simply work with a single ended cable. If you still get no sound and you're sure the amp is operational, the next thing would be to call QSC. . |
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New member Username: MrafkaNJ United States Post Number: 5 Registered: Sep-11 | Thanks for everything, Jan. You really clarified things and helped me a lot. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16721 Registered: May-04 | . You'll be working in some tight quarters with the mini plug. Use a low wattage, low heat iron for those connections. The 1/4" plug should be fine with a 15-25 watt iron or, if you're lucky, a soldering station. Use a continuity checker to make certain you have not accidently shorted the sections of the plug together at the solder joints. It's too easy to do with such small plugs and it could be somewhat dangerous to the amp if you plugged in a fubar'd cable. . |
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New member Username: MrafkaNJ United States Post Number: 6 Registered: Sep-11 | Thanks for the heads up, I'm thinking about getting these plugs: http://www.ebay.com/itm/320747188893 http://www.ebay.com/itm/Canare-F-12-F12-1-8-inch-3-5-mm-Mini-TRS-Connector-New-/ 320747187574 They will be fine, right? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16722 Registered: May-04 | . They should be fine. The most difficult part of soldering the plugs - especially the mini plug - is afixing the tip and ring connections. Too much heat and the dielectric around the post begins to melt which dislocates the pin and it will no longer fit into the jack. It's a fairly tricky job to apply sufficient heat to the parts while not overdoing the heat to the point of damage. Tin both parts individually before you make the connection and then apply just enough heat to allow for good solder flow while making the actual joint. A small heat sink attached at the base of the solder tags might be helpful. Also be careful not to overheat the cable ends to the point the dielctric of the cable begins to shrink back - again a heat sink would be helpful but often gets in the way while soldering such small parts. . |
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Silver Member Username: NencyPost Number: 198 Registered: May-09 | Hello friends nice submitting i like this.... The most important thing to remember when dealing with balanced signals is that you need three parts: the balanced OUTPUT (eg microphone), the balanced cable, and the balanced INPUT (eg mixing desk). If any of these three parts is missing then you will (at best) default to unbalanced mode. If you connect a balanced output to an unbalanced input, you will always have an unbalanced signal path. If you use an unbalanced cable with a balanced input and output you will always be unbalanced. This is VERY IMPORTANT! You can convert an unbalanced signal to a balanced signal using a D.I. box, but we'll save those for another time... Thanks for... |