Amp question.

[Jw_Leonhart]

I'm kind of new to the audio world. I know whata reciever is and what it does, and of course speakers and that. Now what I am confused about is the more complex audio stuff, such as adding an amp to the setup, different wires, crossover, bi-wiring, and all those other things.

My most confusing part is the amp. I see amps and I see of course an input from the reciever and an output again from the amp. Most of the time I only see 4, which would only handle 4 speakers correct? Also, if a top-end reciever can deal out 200-watts of power per speaker what would the point of getting the amp be? It wouldn't make it anymore louder if the speaker only handled 200watts itself right?

If anyone can explain that it would be appreciated. Also, if someone could list some good sites for audio reviews and a place to learn about all this stuff in detail it would be incredibly helpful and appreciated. Thank you.

[dougdrake]

IMO, the idea behind outboard amps is that because they only have to do one job, they can maximize on the components used to do that one job really well, like a larger power supply/transformer, bigger cooling fins, better circuitry, etc... to better handle driving the speakers.

Also, it doesn't necessarily follow that the best amps are found in the best receivers. Sometimes, but not always.

Going with full components (amp, preamp, tuner, etc...) is the final end-game of all this, as you can imagine, which gives total control over each step of the process.

I think, though, one must strike a balance in the overall system. IOW, don't drop $1500 on an amp to drive $500 speakers - probably would be better to spend $1500 on speakers. $ for $, I think investments in speakers give the single biggest improvement in your system.

DD

[JohnA]

Are you HOT out there Doug?!

Wanna buy some electricity, cheap?

[WMcD]

Well wait a minute.

In the old days, and to some extent today, there was the most modular system.

1) A tuner (radio) just supplied a line level out put . FM was hot and then came the need for an outboard multiplex decoder for stereo.

2) A record changer just played records. When magnetic pickup (low output) came into use, you needed a 2.1) phono pre amp to get a line level output. Now sometime transformeres are used.

3) Some people had tape decks with a line level output. (Reel to reel, 8 track, cassette, DAT.)

4) Then came CD players, again with a line level output. And VHS and DVD.

5) Something was needed to switch between the above, and thus there was the "pre amp". This had a selector switch to choose the input. Tone controls and a loudness countour (bass boost mostly) were also in there.

6) All the above were basically at line level (about 1 volt) and something was needed to drive the speakers. Thus you had at least one power amp. Two for stereo. More for multichannel.

7) Then came multi channel processors for 5.1 channel Dolby.

8) Even before 7) "receivers" became popular. They contained 1), 2.1), 5), and 6). Later, 7) was added to make Home Theater receivers. Note, the power amplifiers are built in.

(There was also "integrated amps" which omitted the built in tuner, so was not called a "receiver".)

Some people like the most modular approach. There are claims for better sound with individual components. It also makes sense in any age that you've just gotten the hot new accessory; e.g. the multiplex decoder in the late '50s or the newest digital processor. You might just want to keep what you have and add more support components. It gets expensive and complicated. If you believe "the more toys the better" this has some appeal.

If you're just starting in the game, I would suggest a moderately priced HT receiver. Like Prego sauce, it's (mostly) already in there. They are a lot of bang for the buck. If you need other components to feed the thing, like a CD player, DVD, etc. you might be well served by spending at the same level on components by the same manufacturer.

I would agree that it is best to be a bit moderate on spending on electronics and invest all you feel comfortable with on speakers. Moderately priced electronics from the Pacific Rim can be pretty darn good, you'll get plenty of suggestions from the forum. (I think they're all mostly the same given the same features, like decoders, based on specs. *)

Spending 50% more there may be not getting you lot more. On the other hand, spending 50% more on speakers can make a very large difference. If you can, shoot for a 5.1 speaker (five speakers and a sub) system and receiver. That will protect you investment a bit. Yeah it is big investment but will avoid remorse.

I await the hate mail on *. Smile.

Gil

[WMcD]

Let me add.

Don't now (now!) invest in expensive wire, connectors, bi-wiring. I'm not going to debate the merits of them and muddy the water.

The gold connectors from Radio Shack are reasonably priced and, in my view, more than enough. 16 gauge wire for speakers from RS is good enough too.

Later, if the bug bites, you can experiment with superwire. (I think it is worthless, but you'll get your chance.) Right now you have enough on your plate to stick with middle of the road. You can't go far wrong.

Gil

[Jw_Leonhart]

Ok, so then let me understand this correctly. A Pre-amp is basically a reciever minus it having an internal amp like most recievers today do. The amp itself will drive the speakers, while the pre-amp controls the inputs, decoding, tuner, or any other such thing.

Now as for bi-wiring and all of that, I still do not understand. You say not to do it but I don't even understand what it is in the first place, I don't even know what it does.

Any websites as well?

[WMcD]

Bi wiring refers to the issue of the wire between the output of the receiver's power amplifier output (or a stand alone power amplifier) and the speaker.

It is difficult for me to not get a bit intellectually argumentative about this.

Usually, you have the amp output and run some wire to the speakers and be done with it. All the audio frequencies, in the form of electricity, to the run to the speaker box on one pair of wire.

Of course all the audio frequencies have been moved around the tuners, CD players, DVDs on one connection too. Part of setting up my argument.

In most speaker boxes, we find at least two drivers. Typically a big one for low frequencies (woofer) and one for high frequencies (tweeter). There is also two electrical filters in the box.

One connects to the input wire block to the box and filters out the lows and sends the remaining highs though an internal wire pair to the tweeter. This is a high pass filter.

The other connects to the input wire block and filters out the high and sends the remaining lows to the woofer. This is a low pass filter.

If you look at this going up in frequency, you'll see that that the two filters act to "cross over" the power from the woofer at the low, to the tweeter, at the high. Hence the term "cross over". It is a bit of a misnomer, depending on how you look at it, in that the filter action actually preventing the lows from crossing over to the tweeter, and vice versa.

There are very good reasons for this in the speaker mechanics. This is basically because they have individual characteristics, mechanically, electrically, and acoustically.

In any event the cross over filter divides up the frequecies.

What does this have to do about "bi-wiring" you say.

Some inquiring minds look at the set up and say, Huh? In the feed wire between the amp and the speaker box, couldn't it be that the high frequencies and low frequencies interact in the wire? What can we do to eliminate that interation. (This is not true in any electrical engineering sense, but people believe it.)

The solution to this "problem" is to run two speaker wires to the box from the amp. It also requires that there be some way to connect each wire pair to the inputs of the two filters in the cross over network in the box.

Usually, there is only one pair of input terminals to the box which feed the two filters. Some speaker designs accomodate this by having an input to the box corresponding to the two filter inputs. They are "bridged" with a parallel connection bus bar at the rear of the speaker. The bridge can be removed to allow two wire pair to be connected to the two filters.

That, is bi wiring.

Technically, current (but not voltage) in the high and low frequency feed wires will be limited to the frequencies which the internal filter's pass to the tweeter and woofer.

I, myself, think this is nonsense. There is no interference or compromise due to the highs and lows being transmitted in one wire pair. As pointed out above, all the signals in the chain upstream of the speaker has been on one signal path, not split.

Other people differ. Speaker manufacturers, including Klipsch these days, allow for it in the hardware with the bridging.

I'm not telling you "not to do it". It can't hurt. It doesn't cost much if you're using cheap wire. You do have to make sure the polarity is correct.

I'm just saying that you should not be overly concerned with tweeks like this. Get a basic system up and running with a moderate investment in money. Listen for a while, play with speaker placement, get to know your system.

Then, if you want to tweek, play to your heart's content. I do get a bit annoyed when people get the perception that any given tweek is absolutely necessary from the start. And I get really upset when they're told they have to spend a lot of cash on the tweeks.

Gil

[JohnA]

JW,

A preamp is even less than a receiver minus power amp. They only switch between inputs and control the volume. Some still have tone controls, but a preamp doesn't even have a tuner and mine doesn't have a phono section.

Bi-wiring is running 2 speaker wires to each speaker from each channel of your amplifier. To do it, the speaker has to have 2 wire connections. One connection goes the the woofer only and the other goes to the high frequency drivers. The crossover is specially designed for this. The theory is that using separate wires for the bass and treble prevents powerful magnetic fields created in the low frequencies from affecting the highs. I don't know if it works and I've never been interested in trying.

[Jw_Leonhart]

My home theatre! See how useless it is! Sorry the quality isn't the best guys, I took it on my video camera. Whopping .5 megapixels.

[Jw_Leonhart]

Click for the pictures

Sorry, there is the link.

[dougdrake]

Yes, John, it is freakin' hot here. My car thermometer was 118 yesterday, with humidity in the 40-50's. That may not sound like high humidity, but couple it with 118, and it's no longer a "dry heat." Can you say wet sauna?

[JohnA]

I had heard on the radio your low temp for Wednesday morning was 97F. We've only had 3 or 4 days this year with the high over 90F. It's been a cool summer, so far.