Crazy Idea - Direct connection to Amp (no HU) - Will it work?!?

[navin]

Originally Posted by vebmetal

Question: The Kenwood KAC-8401 has an input sensitivity of 200mV to 5V. Is 200mV low enough to match the pre-out voltage from a mp3 player (or similar devices)? Or do I need to go for something even lower like the Blaupunkt GTA 4 Special Mk II which has a input sensitivity of 100mV to 8V?

200mV is adequate.

[vebmetal]

Thanks navin, what range can this work under? For example, would 300mV be adequate as well? And would there be any advantage of going with a 100mV input sensitivity amp as opposed to a 200mV or 300mV one?

Also, the blaupunkt installer had said that the higher the pre-out voltage of the audio device, the better the sound I would get. He said ideally it should be upwards of 2V. (I imagine the output of a mp3 is somewhere between 100 and 300mV.) Is there any strength in what he says? Or is it just a matter of matching the two - i.e. if the mp3 player gives 200mV and I set the amp to a sensitivity of 200mV, then I get 'optimum' performance?

[panky12345]

Originally Posted by vebmetal

Some things have changed since I last posted, and this is what I am looking at:

tution wale bhaiya ne class mein bataya nahin kya??

[gunbir]

Originally Posted by panky12345

tution wale bhaiya ne class mein bataya nahin kya??

Careful Panky, aisa na ho aap ki class lag jaye...

[anupmathur]

Originally Posted by vebmetal

Also, the blaupunkt installer had said that the higher the pre-out voltage of the audio device, the better the sound I would get.

Wrong.
..the LOUDER the sound you will get.

Originally Posted by vebmetal

i.e. if the mp3 player gives 200mV and I set the amp to a sensitivity of 200mV, then I get 'optimum' performance?

Not quite.
You would need to turn the amp's sensitivity control till you get loud enough output, ie nearly the max that the amp can deliver OR till you're happy with the loudness. If that proves impossible (with the amp's control even at max) you know that your source needs to give higher output.
200 or 300 mV might be too little to drive most power amps to full output. The standard is more like 775 mV RMS.
I'm not familiar with what your amp needs by way of input signal to give it's rated output.

[Sam Kapasi]

by the way Panky, it is spelt as TUITION. Thanks. lol.

[anupmathur]

Originally Posted by Sam Kapasi

by the way Panky, it is spelt as TUITION. Thanks. lol.

But Sam, that's the rigorous spelling; not the local 'phoenetic' one!!

[vebmetal]

^rrrrrrriiiiiiiiiiigght.... coming back to my question is the voltage issue going to be a problem in my setup? Will the low pre-out voltage of the mp3 player mean that I would have to set the input sensitivity very high, and does that mean that I would compromise on the quality of sound?

[Sam Kapasi]

Not really, but because your output is low and the input sensitivity control a.k.a gain control is set high, you are more susceptible to unwanted noises and disturbances.

[vebmetal]

hmmm.. practically speaking how much of a risk am I running in terms of getting said noises and disturbances? The setup would be like this:

Amp:
Placed under passenger seat.
Power connected to battery.
Ground connected to wherever it needs to be.
Speaker wires for front components going under the dash to connect to whatever provisions exist to connect to speakers.
Remote (Turn-On) wire connected to ignition, with a switch in the middle so that the amp is not on always.

Cabling:
Tsunami for amp.
Connection Audison for Speaker wires going from amp to under the dash.
Stock wiring for speakers.

[anupmathur]

Originally Posted by vebmetal

hmmm.. practically speaking how much of a risk am I running in terms of getting said noises and disturbances?

I was following this thread, but there has been an inordinately long silence.
About your query:
Should be alright. However, please note I am not into ICE installs and hence not familiar with the specific hardware you are talking about. YOU are quite familiar with that aspect.
In fact, I'm only answering this as (being a national holiday) it seems that Navin and Sam have headed out already to the neighbourhood pub for their evening W & S!
In case your MP3 player does not have a line out but has only the headphones out, you might need to 'load' your output with an appropriate resistor (8 ohms or 32 ohms, 1/2 W) to achieve best performance. (Sometimes the phones output does not directly give good/clean output when plugged into an amp's line in).

_______________

No offence meant to anyone please!

[vebmetal]

My mp3 player only has a headphone jack. I haven't seen any mp3 player with a line-out. If you know of one, please do let me know because that would solve my problem!! (And anyway a DAP upgrade is due for me). As far as this resistor thing goes, I wouldn't want to do a mod / jugaad to my mp3 player, so do let me know if there is any device (that I can fit after the headphone out) available in the market (India or U.S.) that would do what you describe.

[anupmathur]

What I have described is not a 'jugaad' by a long shot! All it means is that you are providing optimal 'loading' for the MP3 player's phone output by soldering on an appropriate resistor across it's output (anywhere that you find convenient along the whole length of the wire going from MP3 player's phones out to amp's line in) so that it (the player) believes it has a 'headphone' connected to it. That voltage signal across that resistor can then be led to the amp's line in. It's just a resistor 'soldered on' in parallel, IF required.
And I did mention that it is required ONLY in SOME cases. NOT always. Nothing needs to be imported from the U.S.
I only mentioned this point because I am well aware that MP3 players do not have a line out. And, SOMETIMES, the phones output does not exactly 'match' an amplifier's input impedance/characteristic.

[Sam Kapasi]

In any case anup, I do not know of any 8 ohm headphones. Most are 64 or 32 ohms.

And I do not think loading will be necessary.

[anupmathur]

Originally Posted by Sam Kapasi

In any case anup, I do not know of any 8 ohm headphones. Most are 64 or 32 ohms.

That's not my fault Sam. If you look around or do a google, you'll find some. You are right about MOST of them, but that does not mean there are none or that there were none.
That's why I mentioned the 32 ohms resistor. And for that matter there are some at 600 ohms too.
Idea is that once the 'seed' is planted a hobbyist kind of 'gets the idea', right?

Originally Posted by Sam Kapasi

And I do not think loading will be necessary.

Again, I have said the same. But there ARE those cases.