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I always thought no, too much signal was never a bad thing. My dad is now telling me that it is relative to the input allowed by the amp. Basically I have amps that have inputs of .5-2.5 volts. I'm going to be running a line driver to strengthen the signal up to 7 volts. Will that signal fry the inputs on the amps or what? He says yes, I used to think no. Fill me in yall. They are zapco ag model amps, was going to leave that out but thought it might be somewhat relevant. I can't afford to be blowing up amps signal inputs or anything like that. Thanks in advance, someone tell me whether I should be worrying or not. Thanks.--ward
Posts: 116 | From: New Orleans, LA USA | Registered: Oct 2000
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OK, you won't fry anything just by running too much signal voltage into it. The inputs of modern day amps are done with op amps. The input is set up so that you can get maximum power out of the amp with different input signal voltages in this case it is spec'd at .5-2.5V. Most amps will actually allow higher voltage than spec'd, but let's assume your amp can only handle voltages as high as 2.5. When you get above 2.5V you statr to clip the input section, which isn't good because you will end up amplifying a clipped waveform. But you will not hurt the amp, the input section and the outputs don't care what the signal looks like. If the case is that your amp cannot accept more than 2.5V you will just have to keep the gain on the line driver down. But my question is why do you think you need a line driver? Do you have noise issues, are you running multiple amps off the same set of RCAs? What is your current head unit output voltage? The benefit to a line driver is being able to increase the signal voltage so any induced noise on the RCA is much less than the signal. But with modern heads I wouldn't worry since the voltage will be 2V or greater. You won't get any extra power out of your amp as long as your HU can provide enough voltage to run the amp to maximum power, in this case 0.5V.
Posts: 2575 | From: GA | Registered: May 1999
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The line driver was to ensure the signal stayed strong over the 16 ft it had to travel to the rear of the car to the various amps. The signal on the head unit is 4 volts, but I would rather be safe than sorry and would rather run the gain on my amps as low as possible.
Are you saying that the output voltage of the linedriver can't be above 2.5 volts? How would I use a multimeter to test that? Thanks for the reply, hopefully I run accross someone running these particular amps.--ward
Posts: 116 | From: New Orleans, LA USA | Registered: Oct 2000
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Well you can find the input 2 ways either with a voltmeter(preferably one with a true RMS since it is AC voltage) or you can use an oscope which will also allow you to set your input voltage to the point just above clipping since you will be able to see the waveform. Also most amps, once you go above what is spec'd for the input, you can raise the input as high as you want but you can only get a gain of so much this way. By raising the input you will clip the signal and get no more gain. and then there are distortion issues starting and woofers do not like distortion(since this is probably the most common way that woofers blow) so if you are using the line driver to clean up the signal don't over do it cause it does nothing. For more gain you could try raising the DC voltage into the amp to power it but I believe that Zapco amps have a regulated power supply ,in which case the last sentence here won't matter
posted
I'm not saying in your case you can't have more than 2.5V, in almost every amp I have seen they can accept more voltage than they spec. The other thing is that with real music you won't have more than 2.5V unless you are playing music with very heavy bass content at full volume. Im not saying you can't use a line driver, I just don't think you really need one, I don't think you get a benefit in your case. You can get max power out of your amp without one. You will be amplifying your signal by less than 3dB, and the line driver may add more noise than this. 16ft is nothing for a line level signal, you don't need to worry about signal loss over a run this short. And with a 4V output you will be able to run the gain probably as low as it will go anyway. If the gains are sety properly in the first place I see absolutely no need for a liinedriver in your case. I'm not going to tell you not to get one, I just don't want to see someone buy something they don't need when they could spend that money somewhere else.
Posts: 2575 | From: GA | Registered: May 1999
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Good Topic! You might want to see if there are mods available for your model Zapco amp. I am from the PPI Art Series camp, and I know of a mod to raise the max input voltage from 2.5 to 10-12 volts. (PPI sent me the schematics for the A600 amp) It only requires one resistor per channel, so it's not a big mod. Zapco might have a factory available mod, so you would stay under dB Drag comp rules.
posted
Im running a jvc kd-730. It has 2 volt out. It goes through my rockford 5x and out to an orion 260 cobalt and my audio art 100 hc. I find the orion does fine, but the audio art is lacking. The web page says "INPUT SENSITIVITY- 200mv - 7V" so maybe a linedriver will hepl. Im in the process of getting a pld1 right now. Im hoping it'll do the trick.
quote:Originally posted by wizeguy4: Well you can find the input 2 ways either with a voltmeter(preferably one with a true RMS since it is AC voltage) or you can use an oscope which will also allow you to set your input voltage to the point just above clipping since you will be able to see the waveform. Also most amps, once you go above what is spec'd for the input, you can raise the input as high as you want but you can only get a gain of so much this way. By raising the input you will clip the signal and get no more gain. and then there are distortion issues starting and woofers do not like distortion(since this is probably the most common way that woofers blow) so if you are using the line driver to clean up the signal don't over do it cause it does nothing. For more gain you could try raising the DC voltage into the amp to power it but I believe that Zapco amps have a regulated power supply ,in which case the last sentence here won't matter
just as a note:
converting from peak voltage over to RMS equation:
((1/T)*integral((v(t)peak)^2,0,T))^.5
just thought that I would add.
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Posts: 2679 | From: unknown bowels of the underworld | Registered: Aug 2000
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i thought i might mention something here to this semi old post
a deck will not always be putting out its full RCA voltage. say your deck or line driver has 7 volts outputs. that will only happen when the deck is doing full power, ie vclume all the way up. soo.... if you have 7 volts output from your deck (or LD) and the max your amp can take is 4 volts, you will only exceed the amps input when your voltage reaches that 4 volt level. this might be at half volume or three quarters volume.... you should not be getting clipping at the lower volumes... so you can have any amount of voltage comming from your deck or line driver and be OK, as long as you know what you are doing...
Posts: 1854 | From: freezing in FAIRBANKS ALASKA | Registered: Aug 2000
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posted
I thought I might pose this question here also. First I have to McIntosh mc444 whch I plan to run bi-amped to a set of three ways. Seconf the iput voltage says from .5 to 3 volts. If I use Audiocontrol/Zapco/Image Dynamics stuff - they all have an output of atleast 8v - what do I do ?
Posts: 93 | From: NJ | Registered: Nov 2001
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Thanx I think I got it . In other words if I hept the deck volume very very low, and used a line driver - and MOT IMPORTANTLY avoid clipping - I am fine - right? I just did not want to damage the amps - since it says .5 to 3 volts.
Posts: 93 | From: NJ | Registered: Nov 2001
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I need to drop a question in here...? So if my line driver is putting out 8 volts which is where I have it set to, should I set my input sensitivity voltage on my amp at 8 volts...? My amp accepts up to 8 volts...or should I lower the LD voltage to like 4 and keep the input sensitivity down around 4 volts...?
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quote:Originally posted by Johnny-toyo: I need to drop a question in here...? So if my line driver is putting out 8 volts which is where I have it set to, should I set my input sensitivity voltage on my amp at 8 volts...? My amp accepts up to 8 volts...or should I lower the LD voltage to like 4 and keep the input sensitivity down around 4 volts...?
i believe the line driver will do a better job processing the signal than the amps input will, so keep the amps gain at the lowest level possible...
Posts: 1854 | From: freezing in FAIRBANKS ALASKA | Registered: Aug 2000
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i fried 8 orion amps by doing nothing more than adding a line driver!! Posts: 54 | From: springfield mo.u.s.a | Registered: Jul 2001
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