Does voltage on preouts really make a difference??
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Unregistered guest | ok, I got a 1.5 year old JVC deck thats got 4v preouts going to my amp (which can handle 6v). the cd player is being screwy lately so i'm thinking of buying a new one. My question is, looking at the new '05 Alpine models, (more specifically 9851) they only have 2v preouts. so is this gonna make a difference in sound quality by sending a weaker signal to the amp?? on a different subject, what do you guys think of the new Clarion proaudio decks (DXZ555, DXZ655, DXZ755) thanks in advance |
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Bronze Member Username: Makavelie187Concord, California Usa Post Number: 41 Registered: Mar-05 | yes they do matter to a certain extent the higher voltage they put out the cleaner the sound and more accurate bass. |
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Gold Member Username: IlluminatorUSA Post Number: 1653 Registered: Apr-05 | It's like asking the difference between a 500mhz and 600mhz computer processor. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10442 Registered: Dec-03 | a higher line voltage means a higher resolution, cleaner signal at teh other end when it gets to the amplifeir. you'll have better signal to noise ratio, less distortion, and more detail.. a little bit like encoding an mp3 at a higher bitrate if you will. remember the RCA lines carry the audio signal from head unit to amplifiers by using an AC wave form voltage. the greater the amplitude of that voltage (higher voltage) the more detailed the information that waveform can carry since your music essentially is defined by two dimensions of an AC waveform.. amplitude and frequency. Frequency is pre-defined by the source material (CD or radio) so amplitude is your only real variable. When the amplifeir receives that line voltage sinewave, the input stage of the amplifier reconstructs that waveform as accurately as it can, with a tremendously higher amplitude at the output stage... so the more detail you can pack into the input signal, the more detail you'll get out at the other end when it's blown up to a bigger version of the original.. like magnifying a picture under a glass.. you see the flaws more readily at the final, enlarged stage. note a higher line voltage won't make your system any "louder" though.. just cleaner. |
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Bronze Member Username: Biggyg9712Post Number: 52 Registered: Sep-05 | what do multipe outputs do, right now i have a jvc deck with 1 2.5 volt output, and im thinking of getting the pioneer mp7700p deck that has 3 2 volt preouts, will this make my system sound any better? |
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Bronze Member Username: Biggyg9712Post Number: 56 Registered: Sep-05 | wait, the pioneer preimer has 3, 4 volt outputs, will this make a big difference? |
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Silver Member Username: Kd7nfrMontpelier, ID United States Post Number: 847 Registered: Apr-05 | They're probably for your stage speakers (RF, LF, RR, LR) On my Alpine CDA-9833 I have 6 pre-outs at 4volts. |
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Denis_A Unregistered guest | yeah, Alpine seems to be a great company thats reliable and has great features on their decks, but i'm kinda turned off by the fact that their new decks only have 2v preouts. I might go the Clarion route this time around, or maybe even the Pioneer p7700mp Mike mentionned seems to be a good buy. |
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Silver Member Username: Kd7nfrMontpelier, ID United States Post Number: 850 Registered: Apr-05 | Go Eclipse if you have the $. (8v pre-outs) And the difference between 2 and 4 volts on the pre-outs is very small if you have good RCAs. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 367 Registered: Apr-05 | Glasswolf, I'm not sold on your reply. How does a stonger signal become more detailed? IMO, the reason for higher voltage is to reduce stress on the amp. The higher voltage gives the amp a better grab (if you will). My question in support of my inquiry is; How come aduio equipment is rated at higher power when considered using a higher voltage? This is why I am questioning your statement. To me it sounds like higher voltage translates to higher power, instead of detail. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 368 Registered: Apr-05 | I mix live music, thus my username. A mixing board has a gain button for each channel, as one of the first adjutment knobs in the circuitry. The gain knob has functions from negative to positive gain. When the gain is on the positive side, it increases "VOLTAGE" to boost the signal. When the voltage is increased, the volume goes up. The detail does not increase, other than the fact that you are able to hear the lower level background much louder than with the gain down. When you said it increases detail, I imagined the theory of how a CD player processes the signal (oversampling). |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10463 Registered: Dec-03 | mix, try to think of the wave form digitally. if your amplitude is 2 volts, you have, say 5 steps of data from peak to peak. At 4 volts, the amplitude doubles, allowing for up to 10 steps of data from peak to peak. If I had a chalkboard I'd show you. basically the larger teh amplitude of the signal, the more finely you can segregate that waveform into more detailed data. a 2 volt signal is compressed more than a 4 volt signal. I can't put it much more simply than that. "IMO, the reason for higher voltage is to reduce stress on the amp. The higher voltage gives the amp a better grab (if you will)." ok see you're talking opinion. I'm talking about electrical principles. The reason the higher voltage signal is better is because even with some loss in the line, you're going to get a stronger signal at the other end, and it goes back to the old idea of garbage in equals garbage out. The better the signal going to the amplifier, the better it'll come out after it's amplified from a 4 volt signal to a 120 volt signal at the speakers. "How come aduio equipment is rated at higher power when considered using a higher voltage?" because you're now talking about an unregulated power supply. amps*volts=watts. the voltage increases, so does teh wattage at full duty cycle. In a regulated power supply for an amplifier, shifts in voltage are compensated for by using a partial duty cycle so the voltage the amplification stage actually sees remains relatively constant. higher voltage = higher power for an unregulated power supply, yes. however, the input voltage of the head unit has to be matched to teh amplifier's input stage using the input sensitivity adjustment, so regardless of the actual input voltage at teh amplifier, the input stage will still be matched to the input voltage and you'll get the same level of signal to aplify if teh gain is set correctly. if you have too high of a voltage at the input stage, the power supply of the amplifier clips because the input stage is overdriven, and as a result the power supply can't keep clean voltage rails.. so you end up sending DC votlage to the speakers. If your input voltage is too low at teh input stage of the amplifier, you end up using power to amplify the noise floor and a weak audio signal.. so you end up with an amplifier that isn't as loud, but it's because you're trying to amplify a weak noisy signal.. and the result will be a system that sounds like crap regardless of the actual line voltage from the ehad unit, because the amp's gain isn't set right. "The gain knob has functions from negative to positive gain. When the gain is on the positive side, it increases "VOLTAGE" to boost the signal." stop mixing apples and oranges. your mixing board has a GAIN. your car amplifier has an INPUT SENSITIVITY ADJUSTMENT. here's the difference: an actual "gain" has a positive voltage to it, so it actually can boost the voltage of a signal. the input sensitivity on an amplifier simply adds impedance to the line voltage to attenuate it to what the input stage needs for clean amplification within the limits of the power supply voltage rails. This is why I harp so much on the fact that "gain" is a misnomer when talking about car amplifiers. The proper term is, and always has been "input sensitivity." "gain" is just a lot easier to say or type.. so we use it much the way we say "RMS" power instead of the actual, more accurate "continuous" power specs for speakers and amps. am I helping at all? Maybe Jonathan can answer some of this more clearly than I can. He seems to explain things a bit better sometimes. |
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Bronze Member Username: Gpz1100Post Number: 66 Registered: Jul-05 | GW, Excellent clarification why a higher voltage yields less noise at the amp input. Do we want to even discuss output impedance of a HU?  Your comments about gain vs sensitivity are very important. Many folks not in the know call it gain because it can be used to increase (gain) the volume of the final output of the amp. What they don't realize is that this increase in output is a byproduct of the sensitivity adjustment. If an amp has a bass boost function, that can be thought of as a gain for the particular frequency affected. I don't think manufacturer's help the problem either. On my alpine mrv-f545 amp, the documentation refers to it as input level selection in one area, yet on the amp itself it's called the 'GAIN'. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 372 Registered: Apr-05 | Thanks Glass, After so many years as a hobbyist and so many articles, blah blah blah... I appreciate your description of similarities/differences of what is defined as "GAIN". I usually set my GAIN/INPUT SENSITIVITY on my car amps by ear. I have never set them according to voltage let alone using a meter. I am gonna try it. I have always been a fan of headroom so I always run a more powerfull rated amp compared to my speakers rating mostly because I cant afford a high quality amp in the higher rated power handlings. So I use a more powerfull amp to compensate for the loss at higher volumes when cheap amp doesnt control evenly. The higher end amps, especially in home audio, have excellent controll, all the way up. Its too bad Krell or Mark Lenvingson doesnt make car amps, not that I could afford them. To make a long story longer; I have always treated the gain setting as (how much can I get away with) button. I would set it as high as it would play without audible distoortion. I am gonna try the physics aproach and set it according to output voltage/input voltage. If I get a better result I will definetly stick to it. Thanks again for your clarification. |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10480 Registered: Dec-03 | for the record, mark levinson did design an audio system for Lexus, and it's hands down the best factory system I've heard to date. It's only offered on their flagship model car though if I recall. |
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Silver Member Username: MixneffectOrangevale, Ca. USA Post Number: 376 Registered: Apr-05 | I think I remember a commercial that mentioned M L. |
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Need4Bass Unregistered guest | I understand the principals involved here throughly but I have a question. Glass, the peak-to-peak description makes sense, you are basically referring to how an analog signal is represented digitally. The smooth analog sine-wave is more accurately reproduced as a square-wave with more "steps" or a higher-bit rate. However, I was not aware that the pre-amp output from a HU was a digital signal. Wouldn't the output impedeance of the HU be just as, if not more, important than the voltage? |
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Platinum Member Username: GlasswolfWisteria, Lane USA Post Number: 10508 Registered: Dec-03 | pre-amp output is analog, and the impedance measure is stated for most decent head units as is the voltage. I was using the stepped digital signal as a comparison to explain the higher resolution of a higher line voltage, and why you'd get more detail from a signal with more amplitude.. lacking the ability to diagram anything on a board or on paper. |
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Need4Bass Unregistered guest | I follow you on that, but the more I think about it, the more I have trouble grasping the advantage of an analog signal with a higher amplitude for the purpose of signal transfer. I guess its all about the signal-to-noise ratio and the fact that the higher-amplitute carrier will keep the signal component farter from the noise floor. |
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Anonymous | ppl - simply head on over to www.bcae1.com & do a thorough read a few times over |
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Silver Member Username: Lil_jonPost Number: 137 Registered: Jul-05 | how bout i could have got the alpine cd 7990 I forgot all about it got back the auction was done $300 F-it tho Ill get the 8455 Eclipse the best best hu i heard was an old alpine hu well not that old 98 99 great hu build quality must wasnt so good it rarely plays cds you buy and forget about burnt he got an 05 car dont wanna get rid of his navi system and even with an EQ he still cant get that clean music...everything the same minus the hu! glass wolf you think you can mayb do some work on this thing? and make it play burnd cds |
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