[gunbir]

Aseem

They were discussing the 4750... so my comments were specific to that HU. Yes, the 7750 has very bright lights... they should fix that...

When you say 2.2v is too less... how have you come to that conclusion. Please explain to me how much preamp voltage is enough for car audio... Cuz this preamp voltage thing is thrown about so often... and very few people understand it...

[aseem]

Originally Posted by gunbir

Most higher HU models have a dimmer wire which needs to be connected to your "parking lights" circuit. Eg the higher Pioneer HUs even let you set "day brightness" and "night brightness".

I dont think the 4750 has that feature.

Originally Posted by gunbir

Aseem

They were discussing the 4750... so my comments were specific to that HU. Yes, the 7750 has very bright lights... they should fix that...

I think you are contradicting yourself. You had posted about higher Pioneer models having "Dim" feature, and acknowledged that 4750 doesnt have that feature. Later you state you were discussing the 4750??? I had responded to your original post stating that the dim feature doesnt work that well in the Pioneer 7700 (So called higher model) and is very irritating as you cant dim the lights on the knobs using the dim feature as per customer reviews.

Originally Posted by gunbir

Aseem
When you say 2.2v is too less... how have you come to that conclusion. Please explain to me how much preamp voltage is enough for car audio... Cuz this preamp voltage thing is thrown about so often... and very few people understand it...

I am sure you are the one of the few folks who understands it , however below is my take on it.

Firstly I never said 2.2 V is "too less", I said its a petty such an expensive unit doesnt come with 4 V pre-outs.

Here's what an amp does: it takes its input and makes it larger so it can drive speakers. How much larger it can make the input signal is set by the input sensitivity and the maximum power output of the amp. You can turn the input sensitivity all the way up but that does not make the amp put out more power than its max, it just gets to that max level with a smaller input voltage.To show the importance of why 4 V outputs on a head unit are better, lets consider an example. Lets say for example we 2 head units, model A puts out a 1 volt signal and model B puts out a 4 volt signal max. We're connecting these head units to a 25 watt amp. The amp puts out 10 volts.
Power = Voltage^2/Resistance = 10^2/4 = 25watts.
To get maximum output from head A, the gain needs to be 10 (10volts out per 1volt in, 10/1 = 10). Now let's say there's 0.1 volt of noise in the signal. With our gain set at 10 with our input sensitivity control we have amplified the noise to 1 volt. Consider what happens with head B. The gain needs to be only 2.5 to get full output. We still get 10 volts of output but the noise is only 0.25 volts. This noise level is 4 times lower than with head A. By using a higher voltage head unit you can set the gain on your amp lower and thus amplify less noise.

[gunbir]

Aseem

I'm in a hurry right now so heres a short one....

a. What is your 4V Sony Preout model actually giving out.. have you measured it?

b. Do you know why your amp is clipping??

[gunbir]

Originally Posted by aseem

I think you are contradicting yourself. You had posted about higher Pioneer models having "Dim" feature, and acknowledged that 4750 doesnt have that feature. Later you state you were discussing the 4750???

I did not contradict myself... I rarely do. I had made a general statement about the feature existing in higher models. If you read carefully, I said "most higher HUs"... that includes your Sony 8800.. doesnt it. As an example, I mentioned Pioneer without mentioning ANY model. Nobody "discussed" the 7750.

Originally Posted by filcord

Another q on Pio 4750. Is there any way to dim the light output from the HU faceplate at night? It is quite bright and distracting. I was told some HUs have to be connected to the parking lights, when they are turned on, the light from the faceplate gets dimmer. Any experience here?

Filcords query was specific to the 4750. He asked about a feature that exists on higher HUs from Pioneer / Alpine / Sony... My answer was specific to his question.

[aseem]

Originally Posted by gunbir

Aseem
When you say 2.2v is too less... how have you come to that conclusion. Please explain to me how much preamp voltage is enough for car audio... Cuz this preamp voltage thing is thrown about so often... and very few people understand it...

Gunbir, please let me know if what I have posted about pre-amp voltage is correct? Or is 2.2 V better than 4 V?

Originally Posted by gunbir

Aseem

I'm in a hurry right now so heres a short one....

a. What is your 4V Sony Preout model actually giving out.. have you measured it?

b. Do you know why your amp is clipping??

My amplifier is no longer clipping. It was clipping as the gains were not properly set by the installer. I figured that out in the morning with the help of Sam.

No I didnt feel the need or had the time to measure my Sony, nor do I wish to carry this debate further. Thanks for your concern for my system! Peace

[revtech]

i can make the display dimmer on my jvc

if its there on a jvc i dont see why this feature shouldnt be there on pioneers and sonys.


Rev

[aseem]

Originally Posted by revtech

i can make the display dimmer on my jvc

if its there on a jvc i dont see why this feature shouldnt be there on pioneers and sonys.


Rev

Rev this feature is on Sony and Pioneer high range HU's. Just that with Pioneer 7700 (higher HU), although you can dim the display, you cant display the lights coming from the knobs etc. and its very irritating at night!
Rest Sony has lens problems, Pioneer comes without bill and warranty, so I guess JVC is the best bet

[aseem]

Originally Posted by gunbir

Most higher HU models have a dimmer wire which needs to be connected to your "parking lights" circuit. Eg the higher Pioneer HUs even let you set "day brightness" and "night brightness".

I dont think the 4750 has that feature.

Gunbir most higher Pioneer HUs including the Pioneer 7700 suffer from "bright" display related issues which cant be set right using the "dim" feature, thats the only point I wanted to make.

Below is the review for Pioneer DEH-P80MP (another High Pioneer HU) which was returned for the same reason (being annoying display):

Qoute: Written by Jeff, Nashville, TN on August 22, 2005


My biggest gripe is the display though, it constantly changes from dim to bright making it very distracting when driving at night. This alone made me return this unit for something more conventional. If you are really into gadgets and like a lot of flash, this would be a great unit. If you are like me, however, and want something a little easier to use and less showy I would pick a different unit.

http://www.crutchfield.com/S-KncjD4y...130DEHP80M#Tab

Qoute: Written by Todd Bierbaum, DeFuniak Springs, FL on April 22, 2005

I have owned 3 Pioneer head-units over the years and none have disappointed, this one also holds true to that history. Only two things kept me from giving it a 5 of 5. One was that at night the display can be bright even with the dimmer turned on. As a matter of fact there is only a minimal difference between dimmer on and off. Also, the receiver eye for the remote seems to be mounted to the right of the unit.

Same can be read about the Pioneer 6700 and Pioneer 7700 on the links below:

http://www.crutchfield.com/S-KncjD4y...130DEHP670#Tab

http://www.crutchfield.com/S-KncjD4y...130DEHP770#Tab

The only reason I had mentioned this was, that as a forum we tend to highlight the faults and problems the prespective buyers might face. We mention that new Alpines have CD eject problems, we mention Sony has MP3 reading problems, similarly we should highlight problems faced by Pioneer users. Your statement that "dim" feature fixes this issue was misleading as the customers complaint about bright display even after turning that setting on, thats the only point I wanted to bring home.

[pranil]

Thre are three settings which affect the display brightness on Pio 7750 HU. Most users who dont understnad it complain as they are not used correctly.


As usual most PIO units require extensive use of manual to tweak and get best out of them.

Here is the list


1. Display brightness- In Setup feature U can adjust display brightness from 1 to 15 which is very big scale. This can be achived only suing setup mode when HU is off.


2. USe dimmer mode. I.e. when Headlights are on the display dimms.


3. Turn of the reversing feature _ There is a feature ( again in setup) where ther display a;ternates between bule on dark or dark on blue, essentially to save the display burn. Actually this is the most annoying. I found turning this off made the most difference. But to just find out this was annoying me took three days.


Also my suggestion is to turn all graphics off when u dont want top show off your unit to your GF/friens. It better that way.

[gunbir]

thanks pranil, you are one of those people who take time to actually understand the product they're using. I have used the 8650 for a long time and had NO brightness issues.

for other Pioneer HU owners with OEL display, here what you do...

a. When the system is off, press the 'function' button for like 3-4 seconds and you will enter the setup mode. Now go to the Dimmer feature setting

b. Dim the day mode (with parking / headlights off) with levels ranging from 1-15

c. Now switch on your parking / headlights and you will see the brightness changes (this is if your dimmer wire is connected to the lighting circuit). This too you can set anywhere from 1-15

d. Turn off the 'Reversing' feature. As Pranil said, this is actually the most annoying cuz suddenly ALL the pixels light up. On earlier HUs (pre 2004) this couldnt be disabled.

e. Exit Setup mode

f. Turn off all screensavers. The Basic TEXT display works well, gives CD-TEXT / ID3 tag information and no graphics...

By doing all the above your 7750 / 8650 / 9650 brightness can be tamed to comfortable levels.

[gunbir]

Aseem

Since you dont have time to understand or test your HUs pre voltage... I will save you some effort and drive some points home...

If you have decent interconnects (RCA cables) and a decent amp (like the 6100F), you dont require 4v. In fact when your gain was turned all the way up, your input stage was clipping. Do you understand what the gain pot is for now? It is to compensate for low voltage. That said, most of the time, 2.2v is enough! Sometimes even with a 2.2v output the amp gain has to be set to the minimum.

So 4V is RARELY required. Also do you know that your HU (or any for that matter) does not give 4v constant... 4v is only output at a certain volume level, usually near full volume. Do you know how to find out what that point is for your HU. Cuz beyond that point you will be running a clipped output.

Also, "some mfrs" overquote the preamp voltage cuz selling them becomes easier as a lot of people dont have the need or the time to test the product. They simply read the brochure / website and buy it. So a 4v HU may not actually deliver 4v at any point.

Your amp gain also has to be set through measurement. It is not set by ear!! You have to know where and when (in the gain pot setting) your amp delivers clean rated power with respect to incoming voltage. Anything beyond this and you'll be clipping away again.

This Preamp voltage thing is a trend started by some mfrs and it is not a problem if your HU does only 2.2v. And more isnt always better. Some high end HUs are 8v rated and they clip the amps input stages. If there are $300 4v units, there are $1000-3000 hi-fi head units that only output 2V

In fact, since too much preamp voltage is a problem, mfrs like JL Audio even have a switch on their amps that let you set for a "low/high" preamp voltage. Amps without this feature are prone to input stage clipping if set by ear by novice installers.

So Aseem, it is wrong to make sweeping statements that a certain HU is better or worse ONLY because of more Preamp voltage.

[aseem]

Originally Posted by gunbir

Aseem

Since you dont have time to understand or test your HUs pre voltage... I will save you some effort and drive some points home...

If you have decent interconnects (RCA cables) and a decent amp (like the 6100F), you dont require 4v. In fact when your gain was turned all the way up, your input stage was clipping. Do you understand what the gain pot is for now? It is to compensate for low voltage. That said, most of the time, 2.2v is enough! Sometimes even with a 2.2v output the amp gain has to be set to the minimum.

So 4V is RARELY required. Also do you know that your HU (or any for that matter) does not give 4v constant... 4v is only output at a certain volume level, usually near full volume. Do you know how to find out what that point is for your HU. Cuz beyond that point you will be running a clipped output.

Also, "some mfrs" overquote the preamp voltage cuz selling them becomes easier as a lot of people dont have the need or the time to test the product. They simply read the brochure / website and buy it. So a 4v HU may not actually deliver 4v at any point.

Your amp gain also has to be set through measurement. It is not set by ear!! You have to know where and when (in the gain pot setting) your amp delivers clean rated power with respect to incoming voltage. Anything beyond this and you'll be clipping away again.

This Preamp voltage thing is a trend started by some mfrs and it is not a problem if your HU does only 2.2v. And more isnt always better. Some high end HUs are 8v rated and they clip the amps input stages. If there are $300 4v units, there are $1000-3000 hi-fi head units that only output 2V

In fact, since too much preamp voltage is a problem, mfrs like JL Audio even have a switch on their amps that let you set for a "low/high" preamp voltage. Amps without this feature are prone to input stage clipping if set by ear by novice installers.

So Aseem, it is wrong to make sweeping statements that a certain HU is better or worse ONLY because of more Preamp voltage.

Gunbir, firstly lets not divulge from the two issues we are discussing, we can talk about how to set the gain on an amplifier in another thread, as thats not what we are discussing here!

The things we were discussing are:

1) Pioneer high-end HU's have display related problems which can not be fixed by using the "dim" feature

2) Pioneer comes with 2.2V pre-out, and I stated that such a costly unit should offer 4 V as its better compared to 2.2V.

Gunbir, since you state so matter of factly that one should measure the pre-volt outputs of the units before making a statement, I wanted to know did you measure the Sony 7700/8800, and Pioneer 6700/7700 pre-out voltages? Was Pioneer higher than Sony and is Sony lieing?

I acknowledge that you are in audio industry and your opinion is more valued than mine. However in this instance you are not right. We all have something to learn! There are experts more experienced than you and me who state that 4V is better than 2.2V. Thats what drives the manufacturers to advertise higher pre-amp voltage figures. Rest of course we can continue argue for the sake of arguing.

You state that Sony HU give the 4v at high level of volume, and that its variable, but so is true with Pioneer. It will also have 2.2V max and it will be variable. However it will have a lower maximum as compared to the Sony.

Lastly brand apart, and provided the manufacturers are not lieing, 4V pre outs are better than 2.2V based on the facts I had mentioned previously. Its simple "physics", that when you amplify more, you also amplify the noise. Do you disagree with this?

[aseem]

Originally Posted by gunbir

Aseem
If you have decent interconnects (RCA cables) and a decent amp (like the 6100F), you dont require 4v. In fact when your gain was turned all the way up, your input stage was clipping. Do you understand what the gain pot is for now? It is to compensate for low voltage. That said, most of the time, 2.2v is enough! Sometimes even with a 2.2v output the amp gain has to be set to the minimum.

So 4V is RARELY required. Also do you know that your HU (or any for that matter) does not give 4v constant... 4v is only output at a certain volume level, usually near full volume. Do you know how to find out what that point is for your HU. Cuz beyond that point you will be running a clipped output.

Also, "some mfrs" overquote the preamp voltage cuz selling them becomes easier as a lot of people dont have the need or the time to test the product. They simply read the brochure / website and buy it. So a 4v HU may not actually deliver 4v at any point.

This Preamp voltage thing is a trend started by some mfrs and it is not a problem if your HU does only 2.2v. And more isnt always better. Some high end HUs are 8v rated and they clip the amps input stages. If there are $300 4v units, there are $1000-3000 hi-fi head units that only output 2V

So Aseem, it is wrong to make sweeping statements that a certain HU is better or worse ONLY because of more Preamp voltage.

Gunbir when did I make a sweeping statement that a HU is better or worse ONLY because of Preamp output? Please qoute me where I said that and dont twist and turn what I said at your convinience. You are making too many assumptions in your responses. You assume I stated that a good or bad HU is decided purely based on pre-amp outputs, which I never did. You assume that the 2.2v system will have good interconnects, but 4v wont. You are assuming that manufactuerers are misqouting the pre-amp output. You are assuming that 4v in case of Sony is variable, but in case of Pioneer its not.

See you are talking about whats your opinion about 2.2v and 4v, and I am 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.

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.

Originally Posted by gunbir

Some high end HUs are 8v rated and they clip the amps input stages.

Again you are twisting what I said. We are not discussing 8v vs 2v, we are discussing 4v vs 2v. For an 8v system, 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. This is not true for 4v.
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..

Originally Posted by gunbir

Your amp gain also has to be set through measurement. It is not set by ear!! You have to know where and when (in the gain pot setting) your amp delivers clean rated power with respect to incoming voltage. Anything beyond this and you'll be clipping away again.

Stop mixing apples and oranges to prove your point. 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. Many folks dont 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.
The reason I wanted to highlight this as you used the word gain. "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.

If you wish to learn and read more views of other experts who prefer 4v to 2.2v please scroll through the links below:

http://www.carstereo.com/rayfes/head.cfm

Pre-amp outputs: These are must for any serious head unit. Some head units now offer 4 volt outputs instead of the usual 1-2 volts. This can be very beneficial since cars have a lot of electrical noise in them. The 4 volt output is less susceptible to noise, however, you must be certain that the amplifier or crossover being connected to the output can handle 4 volts or you will not be able to use the extra voltage.

http://www.bcae1.com/preoutv.htm

The higher output will allow you to reduce the gains on your amp (or any down line signal processor) which will lower the noise floor of your system.


http://www.faqs.org/faqs/car-audio/part4/

If the noise level inserted due to cabling was 0.1V per cable then the noise level in the signal reaching each of the two amps would be a slightly higher percent of the signal level but not doubled. (this is also why the 4V head unit is favored over the 1V unit for noise immunity: 0.1V noise / 3.76V or 3% is much less than 0.1V noise / 0.95V or 10% even in a one to one connection).

[Autophile]

Aseem,

Thats a nice essay on the output voltage.

Every headunit has a variable voltage output. Thats the only reason for controlling the loudness, your head unit is a preamp (act as a potentiometer). The stated voltage by the manufacturers is the maximum voltage the preamp stage of the headunit reaches at the full volume.

The high volatge output headunits and the line drivers for that matter are the easy way of making powerful systems using low quality amps. So the preamp stage has more gain and the final output stage of the amplifier does not have to work hard and hence manufacturer of the amplifier does not need to spend on expensive op-amps, powersupplies, caps and the heat sinking of the amplifiers.

The clarity part has nothing to do with the output volatge of the head unit its all about the components and the design which goes in designing the amplifier and the headunit.

The most expensive headunits like McIntosh, Denon etc work on 2 Volts that does not mean that they sound bad in front of Pioneers and Sony's and so on.

The noise related issues will be there in the car environment you cannot eradicate them. But you can control them by using good quality interconnects and cables. If one can afford go for the Fully Balanced System and it will take care of the noise.

A bad sounding headunit with 4V or 8V output cannot sound better than a good sounding headunit with 2V output.

The point here is that preamp out voltage should not be the only criteria for selecting or rejecting a headunit.

There are other more important things like S/N Ratio, D-A Convertor, Transport, Power Supply, Interface, Noise of DSP used etc...the list is just endless and probably at the end will come the ouput volts.

For your information one of the most expensive CD Players, Preamplifers and Amplifiers work on 2V.

Specs can never get you sound. If you buy 4v headunit and use it with cheap and poorly designed RCA cables don't even be under an impression that you are getting the best sound.

And moreover if the amplifier does not accept the 4V whats the use of 4V head unit..most of the times you are clipping the input stage of the amplifier which will pass the clipped signal to the output stage hence the whole system is driven into clipping.

By the way Aseem what is the setting you have finally done on the gain (input sensitivity adjustment) pot of your Pioneer 6100. And how have you done it? Because this is what matters more that the equipments and output voltage etc. etc.

If the preamp out of HU and input stage of amp in your system is not calibrated then there is no point of wasting breath by writing long posts.


This is from one of you links about preamp outputs :

"Op-amps:
In general, most op-amps cannot drive their outputs all the way to ground or to the regulated voltage. They may not be able to drive their output within 1.7 volts of either. This means that their output signal is limited to the regulated voltage (9 volts) minus 3.4 volts (1.7 * 2) equals 5.6 volts. Now remember that we are talking about peak-peak voltage output. The RMS voltage is only 35% of the peak to peak values. This means that the output from the op-amp will be limited to 1.96 (2) volts."

"The diagram below shows the relationship between the voltage output levels of each of the types of outputs. The white line would represent the voltage output produced by the op-amp powered by the switching power supply. The green colored waveform, the 4 volt output. The yellow, the 2 volt output.



NOTE:A piece of equipment that has a higher maximum output voltage is not necessarily going to sound better than one which is only capable of 2 volts output. The higher output will allow you to reduce the gains on your amp (or any down line signal processor) which will lower the noise floor of your system. If you are not having trouble with noise (alternator, hiss...), you may not benefit from the extra output voltage. You also need to realize that the voltage may be more than your amplifiers can handle. The extra voltage will not damage the amplifier but if the lowest sensitivity (gain setting) on your amp is 2 volts, and you drive it with anything more than 2 volts, it will cause your amp to clip*.

*This assumes that the gain setting is the voltage that will drive the amp to max power. Some amps are underrated and may have slightly more headroom and therefore will clip at a little higher power."

It is apparent you can Google well... I suggest you read the results before you post contents that contradict your statements.

[aseem]

Originally Posted by Autophile

Aseem,

It is apparent you can Google well... I suggest you read the results before you post contents that contradict your statements.

Its apparent you are here to defend your freind, who made an incorrect statement. I am not contradicting myself, I posted the link below after reading them.

Alpine has the new 985x series of systems. The 9850, 9851,9852,9853 come with 2V pre-outs, only the 9855 comes with a 4v pre out, and Alpine charges a premium for that. What I mentioned was, given the Pioneer head unit costs that much, they should have given 4v as opposed to 2.2v.

For two identical systems having 2.2v and 4v as the only difference, the 4v pre-amp output unit is better, for the reasons I have highlighted. And there is no debate on that, as its not my opinion, its a FACT!