I need a crash course on Amps

[Bozwth]

It looks like I'm going to need an education on amplifiers. I'm planning on using a pair of LSi15's for 2 channel sterio music only from my HK AVR-635. (surround sound will be a totally seperate set of speakers) I can tell that I am going to have to use an amp to power them properly, but I don't have a clue as to what I should get. This is the first time I've taken a look at amps and I have found many brand names that I have never even heard of. I have no idea what size amp I will need and I do not even know what the differece between an amp, pre-amp and an intigrated amp is. Where do I go to get the basic info I need to make a good decision about exactly what I should get and which brands to look for? :confused:

Thanks...

[Skynut]

Brand is up to you.
An amp is just an amp, it amplifies whatever signal it gets.
A pre amp has no amp and is what allows you to switch between sources ie. vcr/tape/cd/dvd/phono ect. It send the signal from the source to the amp and controls the volume.
In integrated is the preamp and amp together usually with a reciever also.

As for the amp you want I would say a good 2 channel high power (200wpc+) or 2 monoblock amps. (2 seperate 1 channel amps)

You need to look into what your budget will be to determine how much you are willing to spend for an amp or two.

[Frank Z]

An amp is just an amp, it amplifies whatever signal it gets.

In a perfect world, yes. In our world, not really. Different amps can and do have an effect on the sound that reaches your ears. For some the difference is very noticable, for others there's no difference.
Audition as many as you can, preferebly side by side. Listen for changes/differences in the clarity, brightness, lack of or more pronounced bass, soundstage (placement of the instruments/vocals), depth of the soundstage, etc.

Most importantly, picking an amp should be fun, not work.

[ND13]

Current, HIGH CURRENT.

[zingo]

I agree. This will be your amp, so shop around and see what you thinks sounds good. If you like it better than other amps you've heard, then buy it. One's ears aren't wrong to them.

[Mike682]

I have no idea what size amp I will need and I do not even know what the differece between an amp, pre-amp and an intigrated amp is

Two good websites for explaining amp design and other audio terms, etc.

http://www.hometheaterhifi.com/volume_1_1/v1n1amps.html

http://www.rane.com/digi-dic.html

[pjdami]

Some brand names to consider (high current) to power LSi's in no particular order:

B&K
Rotel
Parasound
NAD
Sunfire
Outlaw
Musical Fidelity
Krell
Classe

I'd be willing to bet that over 70% of the "regulars" on here have one of these amps.

If you are willing to buy used do some searches for these amps on:

http://www.audiogon.com/

Audiogon is kind of like eBay for music lovers and audiophiles. You can often buy near mint equipment for 1/2 price retail (sometimes more). An excellent way to explore different gear.

[wingnut4772]

Don't forget Earthquake...but I guess if it's just two channels you are looking for, I will second the Outlaw Monoblocks as a solid choice for the 15s.

[tdeluce]

If you are going to power the LSi series definitely check out
the Earthquake Sound Cinenova Grande 3 or 5.

Nothing like 600 watts into the LSi15s to make them come alive :-)

Music is extraordinarily detailed and clear...

[F1nut]

There's more to a good amp than watts alone.

[Frank Z]

There's more to a good amp than watts alone.
Amen! Cuz if the first watt sucks....:D

[tdeluce]

There's more to a good amp than watts alone.

That is true and the Cinenova Grande has it all :-)

[Midnite Mick]

I love my Nuforce reference 9.02's. Very aggressive amplifiers. Throw a little tubes in the mix. Sweet! Some might regard them as a bit pricey though. Just one man's opinion.

Mike

[F1nut]

That is true and the Cinenova Grande has it all :-)

I'm can't say how one sounds as I've never heard one, so I'll take your word that it has it all. However, I'm always leary of a company that doesn't publish much info about their products. It begs the question, what are they hiding?

[Skynut]

I'm can't say how one sounds as I've never heard one, so I'll take your word that it has it all. However, I'm always leary of a company that doesn't publish much info about their products. It begs the question, what are they hiding?


Good point. I never looked into the Cinema Grande but if I was checking out amps and the one I wanted did not give me all the specs the competition gives it would make me think.

[AndyGwis]

Just curious, how do older Carvers stack up to the other amps mentioned? I know Sunfire is up there, and that's the new Carver. . . are the older ones (pre 1995) as well regarded as Adcom, NAD, Rotel, etc.?

I inherited a couple little tfm-6cb's, just curious how Carvers stack up to the rest.

[McLoki]

Here is a decent (recent) thread that turned into some basic info on amps. (http://www.polkaudio.com/forums/showthread.php?t=38918) (starting at post #29 or so)

I will throw in the recommendation for Cinepro. I am sure it is not the be all end all amp, but it is better than any other equipment I expect to see in my room in the near future. (i.e. it will survive a number of upgrades around here...)

Michael

[jakelm]

I would put Carver in the same class as the amps above. I rebuilt my older Hafler dh-200 and I'll tell you that with just 100wpc @ 8ohms, it blows away alot of amps that are rated at 200-300wpc @ 8ohms. Take HK , one of their A\V recievers are rated at only 60wpc. But HK blows alot of other brands that are rated with much higher wattage (Sony, Yamaha, Kenwood, BOSE) out of the water (IMO).

IT'S NOT THE QUANTITY ...IT'S THE QUALITY!!!

[Bozwth]

That's a lot of good information. Here's a few more questions if you don't mind...

Am I correct in assuming that my receiver will function as a "pre-amp" when I use a seperate amplifier through the pre-outs? And I will not be adding power on top of what the internal amp in my reciever puts out, but will be bypassing it alltogether and will be only using the external amp to power the speakers?

That's quite a list on names to choose from, are there any brands that I should stay away from? What are the differences between the expensive ones and the cheap ones?

I've heard the terms "bright and warm". How do I tell which one a particular amp has?

Would I need a special amp to drive 4ohm speakers?

Is there a "latest and greatest" technology to look for? And what kind of specs should I look for in a good amp?

I'll try to demo a few, but wouldn't I need to hear them on the same equipment that I'll be using to get a good idea as to what it will sound like when I get it home?

Thanks again for the help...

[aaharvel]

That's a lot of good information. Here's a few more questions if you don't mind...

1. Am I correct in assuming that my receiver will function as a "pre-amp" when I use a seperate amplifier through the pre-outs? And I will not be adding power on top of what the internal amp in my reciever puts out, but will be bypassing it alltogether and will be only using the external amp to power the speakers?

2. are there any brands that I should stay away from?

3. What are the differences between the expensive ones and the cheap ones?

4. I've heard the terms "bright and warm". How do I tell which one a particular amp has?

5. Would I need a special amp to drive 4ohm speakers?

6. Is there a "latest and greatest" technology to look for? And what kind of specs should I look for in a good amp?

7. I'll try to demo a few, but wouldn't I need to hear them on the same equipment that I'll be using to get a good idea as to what it will sound like when I get it home?

Thanks again for the help...

1. yes
2. most separate amps are built well. It's the tonal characteristics that vary.
3. the size of the power supply, true doubling of wattage on 4ohm vs. 8ohm speakers.
4. Listen to them and you will know.
5. As long as it advertises 4ohm specs, but preferably one with higher current and a beefer power supply.
6. Amps don't evolve much. Look for 4ohm specs, and how they compare to the 8ohm. The higher, the better.
7. Yes if possible.

[John K.]

Boz, since you haven't actually done this yet, your question would appear to be premature at best and there's no way that you can "tell" that you'd need a separate amp. Your 635 is quite powerful and can put at least 150 watts maximum into 4 ohms. Unless you'd be listening to music with an exceptionally wide dynamic range and playing at an unusually high average sound level this would be more than enough for your Lsi15s. At a minimum you should try it out instead of assuming a problem that most likely wouldn't arise.

[F1nut]

And that coming from a guy with a boombox. :rolleyes:

[Bozwth]

I am planning on diving the speakers with my reciever amp initially. Just not too aggressively. Mainly because their are so many amp choices available and the fact that it's going to take me a while to sift though all of the hidden differences.

I didn't realize that I could have problems without an external amp. I was under the impression that an external amp would let me get the kind of music out of the LSi's that they are capable of, what Polk intended, even at low volumes. Is this not why people normally use external amps? Can I damage my reciever or speakers if they are not properly matched?

[AndyGwis]

Boz,

I also have an HK 635, which is plenty powerful enough to push my lowly Monitor 60s, but I decided to hook up some external amps just to play around. They sound great! I prefer listening to 2-channel now much moreso than before, even without having really good speakers like the LSis which everyone says need 250wpc to really open them up.

You can buy and sell used amps without losing much money (if any). Try some out off Audiogon or ebay for a few hundred bucks. Keep until you find better if you like them, sell them right away if you don't. You'll likely get most or all of your money back. Can't hurt to try them out.

[Bozwth]

I'm sure that's what I'll do, I haven't a clue as to where I would go to demo them anyway. Are there any two channel amps out there that have become the big favorites for matching up specifically with the Lsi 15's?

[Bozwth]

Also, Is there a maximum output that I should stay under so that I do not damage the speakers?

[Bozwth]

How can I tell which amps are "high current" amps? Is it reveiled by the amount of watt per channel increase when going from 8ohms to 4ohms?

[cfrizz]

Hi Boz. It is better to have too much power rather than not enough! Buy as much as you can afford or as high a wattage as the speaker takes!

I would assume (but I could be wrong) that if it is just an amplifier than that automatically makes it high current.

Refer to PJDami's post for great high current amps. You can't go wrong with any of them.

[Tour2ma]

Boz, yes to an extent you can infer an amp is high current amp by how close its rating comes to dounbling when the impedence rating drops from 8 to 4. Many amps also have published peak-to-peak current ratings. Just curious, how do older Carvers stack up to the other amps mentioned? I know Sunfire is up there, and that's the new Carver. . . are the older ones (pre 1995) as well regarded as Adcom, NAD, Rotel, etc.?

I inherited a couple little tfm-6cb's, just curious how Carvers stack up to the rest.Never heard of the 6cb model. Guessing it came in the post Bob Carver era.

Old Carvers have their backers and detractors, not much middle ground. I ran an M-1.5t for years. Loved it and still own it, and a couple other models. Great bang for the buck in their day

EDIT: And to the question above on speaker rating vs. amp rating, its simply not an issue for any owner possessing common sense. Your ears are all the protection a speaker needs.