JVC head unit choice
#1
Am looking at a new head unit. Narrowed choice to jvc kd-sx985 and kd-LH2000. Seems to me the 985's only differences is a motorised face and 4 volt preouts but is an older model range. I can get the Lh2000 for $150NZ cheaper. What do the experts think? Does the 4 volt vs 2 volt make much difference. Also what sort of connection goes between the telephone mute and my nokia car kit?
#2
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(I've just assumed that you're talking about subs and that's all that I have experience of when it comes to different voltages).
An amplifier has to take a small input signal from the stereo and <u>amplify</u> it into a big output signal to run the speakers. So, if it starts with a bigger signal, then it can:
a) give you an even stronger output signal (more volume / punch / rumble) into your speakers
or b) be turned down a bit so that it doesn't have to work so hard to give you the same output.
I'm not an expert on amps but these are the results I found a few years ago when my 2v stereo signal was feeding a cheap amp that was running a couple of 12" subs. When I fed the stereo into an active crossover with variable signal boost, I was then able to feed a punchier signal into the subs and the difference was significant. Incidentally, I wouldn't recommend a cheap active crossover in conjunction with an amp that's running full-range speakers - you lose quite a bit of clarity and end up wih a 'loud but cheap' sound.
An amplifier has to take a small input signal from the stereo and <u>amplify</u> it into a big output signal to run the speakers. So, if it starts with a bigger signal, then it can:
a) give you an even stronger output signal (more volume / punch / rumble) into your speakers
or b) be turned down a bit so that it doesn't have to work so hard to give you the same output.
I'm not an expert on amps but these are the results I found a few years ago when my 2v stereo signal was feeding a cheap amp that was running a couple of 12" subs. When I fed the stereo into an active crossover with variable signal boost, I was then able to feed a punchier signal into the subs and the difference was significant. Incidentally, I wouldn't recommend a cheap active crossover in conjunction with an amp that's running full-range speakers - you lose quite a bit of clarity and end up wih a 'loud but cheap' sound.
#3
The difference between 4v and 2v should be **** all in theory. A 4v signal will be less susceptible to noise, as the signal is at a much higher level relatively than the noise.
All amps have a gain control which is a little like a volume control. To produce maximum output from the amp, you need to set the gain control appropriately. Whether the input signal is 2V or 4V should not matter one bit - for 2v, the gain setting will be higher than for 4v. As the gain stage takes naff all power to drive, this will not effect the amp's output/efficiency/...
Saying that, someone has claimed a dB increase when competing in SPL by upping input voltage, but that could be for a variety of reasons not necessarily down to gain.
Cheers,
Nick.
All amps have a gain control which is a little like a volume control. To produce maximum output from the amp, you need to set the gain control appropriately. Whether the input signal is 2V or 4V should not matter one bit - for 2v, the gain setting will be higher than for 4v. As the gain stage takes naff all power to drive, this will not effect the amp's output/efficiency/...
Saying that, someone has claimed a dB increase when competing in SPL by upping input voltage, but that could be for a variety of reasons not necessarily down to gain.
Cheers,
Nick.
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Oh (embarrassed face). If Chiark is a moderator, I guess he knows this stuff more than me. Sorry if I was talking complete rubbish - I was talking from experience .... but it was a long time ago. Maybe I should stop buying such cheap amps !
#6
no need to apologise, it's just as likely that I'm wrong - "moderator" doesn't mean I have a clue what I'm talking about
Theory is that it shouldn't made a difference other than to lower the noise floor of a system, but someone has found an improvement in SPL when competing... But this could be for a variety of reasons and shouldn't be to do with gains...
Theory is that it shouldn't made a difference other than to lower the noise floor of a system, but someone has found an improvement in SPL when competing... But this could be for a variety of reasons and shouldn't be to do with gains...
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