Amplifying RCA signals?

[therobby3]

I'm not to indepths with amplifier and how they work, as I haven't gotten one quite yet. But what I'm wondering is I have my main stereo which I have playing inputs off of RCA wires, which then obviously output to the speakers. The loudness is determined by the volume on my stereo as well as the loudness on the output of the signal in the RCA cables going to the stereo. So when turning both devices all the way up I have reached my max volume. Now I am wondering if I amplified the initial signal going through the RCA cables if that would simply result in an overall increase in loudness, or if it would sound distorted and lower the quality. The stereo is a 300 watt stereo so in essense this would seem like it could raise that output. I'm not sure really. Let me know if anybody knows what I'm talking about or has any ideas. Thanks.

[markw]

I'll word this as simply as possible.

Your amplifier can put out only so many watts without distorting.

Depending on how "loud" that signal coming in is, it may be reached at a low setting or a high setting on the volume control.

To reach the same output level, a low level signal coming in will have you to turn the volume control up higher than you would for a high level signal, which will need the volume set lower.

In either case, the amp is still capable of the same thing. It's only a matter of how you have to set the volume control before you run out of clean power and start distorting.

Incidentally, those "RCA signals" you refer to are called "line level" in this field, and generally range from 1 to 10 volts with very low current.

[therobby3]

Alright thanks. Makes sense, just wanted to make sure that's how it was, I guess I'll just buy an amplifier down the road.

[Smokey]

Now I am wondering if I amplified the initial signal going through the RCA cables if that would simply result in an overall increase in loudness, or if it would sound distorted and lower the quality.

RCA input and output circuits are designed with maximum of 1 volt for signal amplitude. If you increase this value (or amplify it) beyond 1 volt, it will saturate RCA input circuit and you will get distortion no matter what the volume control is set at.

[markw]

RCA input and output circuits are designed with maximum of 1 volt for signal amplitude. If you increase this value (or amplify it) beyond 1 volt, it will saturate RCA input circuit and you will get distortion no matter what the volume control is set at.Granted. while "line level" is speced for about one volt for source units, some units with variable outputs, such as preamps, are capable of a much higher output. This is to allow for the unknown gain of the following unit.

to wit:

http://nadelectronics.com/products/hifi-amplifiers/C162-Stereo-Preamplifier/specs

http://www.adcom.com/data/manuals/gfp715_manual_v1.pdf

There are others as well.

[Smokey]

Granted. while "line level" is speced for about one volt for source units, some units with variable outputs, such as preamps, are capable of a much higher output. This is to allow for the unknown gain of the following unit.

That is interesting. Could you give an example or application where higher than "line voltage" is applied?

I looked at NAD C272 Stereo Power Amplifier specification and it have Input Sensitivity rating of 1.38V.

http://www.frankprowsehifi.com.au/ASP/ProductDetail.asp?PrevID=3&CategoryID=70

[markw]

Why not ask the engineers why they designed them with so much output potential?

Obviously, the engineers that design them had their reasons but, as the preamp specs show, this voltage can be well over one volt. Maybe because they believe that it's better to have more than you need as opposed to needing more than you have? Maybe different power amps have different sensitivity and gain?

Of course, when you get to designing and manufacturing your own products you can do it your way and prove yourself right in that instance but, until then, have fun dealing with the reality that this line level signal can be well over one volt.

[Smokey]

Here is a thought: May be having 15v output capability mean that it can drive passive amplifier also (such as magnetic amplifiers). It starting to make sense now :idea:

[Feanor]

....
Now I am wondering if I amplified the initial signal going through the RCA cables if that would simply result in an overall increase in loudness, or if it would sound distorted and lower the quality. ... Thanks.

How many difference sources do you have feeding the amplfier? Do they all have low volume? If so, the problem is the amplifier.

If you could possibly can borrow another amp and see if has the same problem? I'd bet it won't. I think the your amp has a failure at some stage of amplification, in which case amplfying the input signal is not a solution.

[therobby3]

Aww, no no, everything's working to par how it should, I was just wondering if I could amplify the line level input's a great deal and have a essential overall increase in the volume the speakers output. But I see now it can't be magnified much over the amplifier's watt ratting without it sounding distorted.

[Feanor]

Aww, no no, everything's working to par how it should, I was just wondering if I could amplify the line level input's a great deal and have a essential overall increase in the volume the speakers output. But I see now it can't be magnified much over the amplifier's watt ratting without it sounding distorted.

What markw and smokey have told you is valid and you are understanding it. I just wondered if the issue was that the volume on your amplfier is set at maximum, (i.e. maximum "gain"), but your volume still isn't all that loud: that would indicate a gain, (low voltage), problem in circuitry. This problem might have been in your source or in your amp. However if the problem is that you are beginning to get distortion at a certain point before maximum gain, then a more powerful amp is in order.

[therobby3]

that would probably seem right, lol but it's all good, i didnt have any problems with anything before, i was justa wonderin'. =D