|
New member Username: Odd_barPost Number: 1 Registered: Dec-11 | Hi I run a bar and had rented a 4 channel amp and mixer from a local company but used my own speakers which are apart mask 6. I used this for over 2 months and had no problems. Now i got a new 4 channel amp. On the weekend when i have the music a little louder and for a longer period of time the speakers cut out. The apart speakers have a cut out protection system on them to stop any long term damage . This is what is happening, a red led comes on and then 10 seconds later the speakers turn off . I know something is wrong but with the old amp i never had any problems and played the music for a longer period of time. The speakers are in parrell 2 on each channel making each channel 4ohms . the speakers are wired the same as before so i dont think the problem lies here. The new amp is an Alto MC250.4 and the mixer is a Alto zmx 52. I had some problems with making the mixer work with the right cables . it works now but only if i turn the balance all the way to the right or all the way to the left. I think this is the problem but dont know what this is doing to the speakers. Is the mixer broke or do i need different cables any help would be great . i tried to put as much info as i could with out going on for to much thanks |
|
Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16967 Registered: May-04 | . First, check your speaker connections to the amplifier. A single strand of stray wire will appear to the amp as a short and will shut down the system. Amps are not equal despite looking so on paper. It's possible the new amp just isn't as happy with a low impedance, four Ohm load. Speakers are not just one impedance, their load actually deviates across the frequency and. This could present a much lower than the nominal - or average - load. You might want to look into an autoformer type of speaker selection box. Autoformers will maintain a steady impedance load to the amp. Or wire the speakers in series which will double the nominal impedance but give up just a bit of volume. Higher impedance is always more desireable than lower. Make sure the amp has lots of ventilation, adding a fan might be of help. It shouldn't be shoved into a cabinet but rather sitting where it can get plenty of air flow from all sides, top and bottom. The mixer should only deal with the inputs and shouldn't cause the amp to shut down unless tthe mixer itself has problems. You obviously should have the balance set to "0", not max left or right. Check your set up of the mixer and make certain you have your cables sorted out as needed. If you are running with XLR's, make certain the mixer has a "hot" pin which is identical to your cables - normally either pin 1 or 2 but this is not a convention which is constant across all manufacturers. . |
|
New member Username: Odd_barPost Number: 2 Registered: Dec-11 | thanks Jan I dont think there is a problem with the amp there are no shorts, its takes a long time before the speaker cut off . It is a 4ohm amp can i still put my speakers in series so they will have 16 ohms will this be ok ? I think the problem is coming from the mixer to the amp and thats why i have to turn it to left or right to get it to work. The input on the back of the amp is for bare wires like an out put. I have never had an amp like this before, the company i got it from said just strip the end off from a red and white phono cable and put that in, there are three input holes + - and a thrid whole which i have nothing going into it. Take a look at the design on this website if you like to get a better picture http://www.solotechnic.co.uk/index.php?id=ALTMC250-4&product=Alto_MC250-4_4_Chan nel_Power_Amplifier# Should i be using a different cable ? |
|
Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16968 Registered: May-04 | . Your link doesn't work. If you want to place a link on this forum, try this; first, place a backslash ("\") then put "link{" into the post. Immediately follow that with your url. Place a comma right after the url and then repeat the address. Close the link with a "}". That should provide a workable link. I think I found a sheet on your amplifier and mixer. http://www.altoproaudio.com/downloads/ZMX52%20-%20Quickstart%20Guide%20-%20v1.2.pdf http://legacy.altoproaudio.com/admin/_static/files/prodotti/122242867333661/122449352318925.pdf I hate to be dense, but where the he11 are the outputs on the mixer? Are you taking the output from "Main Mix"? That's labelled as an unbalanced line but, from what the PDF on the amp states, the amp is expecting balanced line inputs. The third connection point for the amp's inputs is labelled as a ground. Balanced lines separate the ground/shield from the "-" and the "+" line conductors while unbalanced lines bundle the ground/shield/"-" together. One - the balanced line - requires three conductors while the other - the unbalanced line - requires only two conductors. That shouldn't affect the speakers' performance but that would possibly account for the pan to the extreme left/right. I hate to say this but you're dealing with BS Chinese components that try to be everything to everyone and they seldom manage to do so without lots of headaches in set up. I'd check again to make sure you have the right input connections. The mixer shouldn't require the extreme channel pan. What sources are you running into this mixer? Are they a balanced or unbalanced line output? The PDF indicates only "Line 1" can be a balanced line in. Which input(s) on the mixer are you using? Are any of the peak or clipping lights flashing on peaks of volume just before the speakers shut down? The mixer really shouldn't result in the speakers shutting down. Not unless you have the dip switches set to run the amp in a mode that you aren't also connecting speakers in an appropriate fashion. You can check this by disconnecting the mixer from the amp and running just the amp connected to the speakers. If any of your sources have an adjustable output, run that source player directly into the amp and use the vc on the player as your volume control. If the amp continues to run without problems, then the problem exists in front of the amp or in your set up of the amp. The exception here would be if, on the weekends, you are running the amp into clipping and over voltaging the speakers. If the amp still shuts down, then the problem exists after the mixer and would most likely be the result of incorrect set up (dip switches and speaker connections) or you are overdriving the amp into a load it doesn't prefer. dip switches along with incorrect speaker hook up normally wouldn't allow the amp to work for long at any volume however. I'd double check all the switches and your speaker connections to make certain you have this amp set up to run as, I expect, a "stereo" amp. Don't set the switches to run as a parallel or bridged connection. Then make sure you only have speaker cable connections to outputs 1 & 2 and only to the "+" and "-" terminals of those outputs. "I dont think there is a problem with the amp there are no shorts, its takes a long time before the speaker cut off . It is a 4ohm amp can i still put my speakers in series so they will have 16 ohms will this be ok ?" Maybe the connections are good, but it doesn't hurt to check. Some amps shut down quickly with low impedance loads or shorts and some will try to tough it through. Check the connections anyway just to say with certainty they are not a problem. I've never seen a solid state amp that wouldn't work into a higher impedance load. As I said, higher impedance is always more acceptable than lower. The amp won't produce quite as much peak wattage but you won't even notice the difference between the eight and sixteen Ohm output, I promise. If there is a large difference, then there's a more serious problem with the amp I would say. But you can also check this by only connecting one pair of speakers per channel to arrive at an eight Ohm load on the amp rather than your (two pair/parallel) four Ohm set up. If the amp continues to run into an eight Ohm load at the volume you desire, the set up is OK but your amp can't deal with the low impedance of the parallel speaker set up. If that's the case, you have a four channel amplifier and there's no need to parallel two pairs of speakers into one channel's outputs. Ask how to properly split the output of the mixer to common run lines to each channel's input and run the amp as a four channel system. You don't have any tone controls on the mixer jacked up do you? That requires more power from the amp and will cause it to shut down sooner into a low impedance load. I don't know your speakers or their protection circuit. But most speakers in this price range have rather little sophistication to any protection devices they include. Mostly, they are there to protect from over wattage (voltage) or clipping conditions in the amp. How loud is, " On the weekend ... i have the music a little louder and for a longer period of time"? Does the system run normally at lower volumes during the week? . |
|
New member Username: Odd_barPost Number: 3 Registered: Dec-11 | Thanks Jan I run 1 input to the mixer from my pc. It goes in line 1 which says " line 1 bal/unbal" and none of the peak lights ever come on i turn the mixer down if they do. The amp also has peak lights which never come on. The amp it self never turns off, it is just the speakers which turn off. From what you say i must be sending to much voltage to the speakers which in turn must make them shut down. Is there a way to stop this? As i said before i used the same speakers with a different amp and they never cut out before and were used for a longer period of time and what seems to be the same volume or there abouts. Also which cable would be best to buy for the out of the mixer going into the amp so i can play the music with out turning the balance all the way to the left or right . Thank you for your help Jan. |
|
Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16970 Registered: May-04 | . Voltage and current are the two working components of watts. To achieve the same acoustic output with the same speakers two amplifiers must produce identical amounts of voltage and current into the load of the speakers. The most common type of speaker (or amplifier) protection device would react to higher than acceptable levels of voltage and current - just as a fuse or circuit breaker would. With the same speakers in the system, there should be roughly identical amounts of voltage and current running to the speakers to obtain similar output volume levels with two amplifiers. The speakers will determine the voltage and current draw from the amp. "X" amount of voltage and "Y" amount of current (amperage) make up the same amount of watts onto an identical load. The amp can produce more voltage and less current or the other way around, but the two components must equal the same wattage. So four volts and two amps or two volts and four amps still result in the same number of watts coming into the same speaker. The most basic answer to your question, "From what you say i must be sending to much voltage to the speakers which in turn must make them shut down. Is there a way to stop this?", is to turn down the volume of the system. Why the speakers shut down with one amp and not the other is unclear. And, since I'm unfamiliar with the protection circuit on your speakers, I can't provide a clear answer for exactly why they are shutting down. My guess would be the new amp can push less/more current through the low impedance load of the parallelled speaker pairs. However, if you are playing at identical volume levels with both amps, this slight difference in voltage/current delivery shouldn't make for dramatic changes in speaker performance. The only way to check this would be to replace the new amp with the old to therefore determine whether the speakers still shut down at identical levels. That would begin to lead you toward the problematic component, cabling or failing speaker. It's always possible the speakers are simply failing and they are doing so in coincidence with the addition of the new amplifier. I certainly wouldn't make that my first guess but such things do happen and adding a new component is simply a red herring when sorting through the problems. You might want to get a loaner amp for a weekend to determine whether the problem is related to the amp now in the system. Since there are no clear answers to your situation, sometimes you have to go through a basic process of elimination to make certain you're even looking in the right direction. If it were my system, however, I would at least bring the problem to the attention of the retailer who sold you the new amplifier. Possibly they can loan you another amp to use in the system. If that amp shuts down the speakers at identical volumes, then I would begin to suspect a problem either in the speakers or the cabing to the speakers. Each time you trip a protection circuit you weaken the circuit slightly and it will eventually trip at lower and lower input levels or not at all in which case you risk damaging the component. Before you do that though, I would recheck the cabling and run a single pair of speakers per channel just to eliminate any possiblity you've missed something and to determine whether the amp just isn't happy with the load from the speakers. While only the speakers shut down, there must be a reason for this and in all probability that reason is in the amplifier or cabling. Running the amp as a four channel system - one pair of speakers per channel - is the best way to present a more stable load to the amp. Or run the speakers in series to raise the overall load on the amp. Higher overall impedance is always the more desireable option in that even in four channel mode, the amp is still drawing its voltage and current from the same single power supply. You're running an unbalanced line through the system, an unbalanced - "single ended" - system requires two conductors and a shield for interconnect cabling. But the amp - according to the owner's manual - expects to see a balanced line which requires three conductors. Balanced amps can accept an unbalanced line but how you want to wire the system isn't aways consistent from one component to the next. You're going to have to contact the manufacturer's rep or service department for accurate instructions on wiring the mixer to the amp. I don't want to tell you to do something that might damage the system. . |