Help me with amplifier terminology (1 Viewer)

[Richard Harvey]

One of my favorite mags to flip through is What Hi-Fi from the U.K. But, it occurs to me that I'm not clear on alot of different amp definitions, since I have no idea what some of this equipment would be used for. Can someone give me some basic clarity? Here are my questions:

I own a Denon 2802. I bought this because it has full pre/pro outputs. Now, let's say I wanted to independently power my main speakers. Would I buy a:

(a) Stereo amp
(b) Preamp
(c) Power amp

If the answer is (b), why is it called a preamp, since my receiver is pre-processing THEN sending the signal for post-amplification? (which is why I'm assuming the answer is not (b)!)

What Hi-Fi breaks down purchase lists into these categories. What is the difference? I always thought a preamp was used to take a low input signal (like LP) and boost it, but given the wattages on these preamps they must be used for post-amplification. Is this right? If so, how does a preamp differ from a power amp? Is the only difference from a power amp and stereo amp that one handles more than 2 channels, and the other only 2?

Then there is a device called a Processor. Again, I thought this was what I already get in a HT receiver to decode 5.1, 6.1, or 7.1 material. But, given the prices I'm seeing (>$2000) obviously a Processor does much more than I think. How do they differ from your typical multichannel HT receiver?

Thanks for any help!

Rich

 

[Valerie Brown]

Hi Richard,
Here's a useful glossary of terms @ www.jbl.com :
http://www.jbl.com/home/product_supp...ary.asp?Char=A
There is also a Home Audio FAQ @ www.klipsch.com that you may find useful.
There are definitely more qualified people here to answer your questions, but from what your describing, it sound like you would want Power Amp(s) to power your speakers, independently.
A Receiver is a Tuner/Preamp (Pre/Pro)/Power Amps.
Therefore if you were to buy separates, you would get a
Tuner/Preamp (Pre/Pro)/Power Amp(s), independently.
I have an Integrated-Amp, which is a Preamp (Pre/Pro) and Amps.
Tuner: Radio Frequencies
Preamp (Pre/Pro): An Audio Processor/Selector (eg: Balance/Bass/Treble or/also Phono/CD/Tape1/Tape2, etc....)
Power Amp(s): Power Source. In a Pre/Pro situation would link between the Speakers and your Receiver.
There are also Processors for sound-formats like DTS and Dolby Digital EX. If your Receiver/DVD Player does "process" the signal, you would need an additional Processor to hear the signal.
I don't think you need to worry about a Processor, because your Receiver is a fairly recent model.
Hope this helps. I think it's correct, but if not someone will enlighten us!

 

[John Garcia]

To independently power your mains only, you would buy a stereo (2 ch) amp OR two mono-blocks (each a single channel).

 

[Kevin U]

Hello Richard,
Let me try to shed some light for you.
A preamp (or Pre Pro as they are called for audio and video sources) is an input box to hook your sources to. Things like a DVD player, CD player, VCRs, AM/FM tuners, etc. They can be audio only or full AV systems.

You would need to use a seperate power amp to send these sources signals (after being sufficiently amplified) to your speakers. A pre amp will generally NOT have any speaker output terminals. You would run cables from the PRE OUT terminals of the pre/pro to the corresponding inputs of the amp. If you are trying to have a 5.1 Dolby Digital system (which is 2 front main speakers, two rear surround speakers, a center channel speaker, and a subwoofer being the .1 section) you will need a 5 channel power amp. The subwoofer is usually powered with its own amp so you only need to power the other five speakers. However you would still run a audio cable from the subwoofer output of the PrePro to the line level input of the subwoofer, which carries the unamplified signal to the subwoofer). Otherwise a standard 2 channel stereo amp will be needed for powering the 2 main speakers of your stereo system.

There are some units called Integrated Amps that are the Pre amp AND power amp together in one box but I think these are mainly used for audio only systems these days.

Many people who dont want all those seperate components just buy an A/V reciever (which come in 5.1, 6.1 and now 7.1 dolby digital audio formats) which has all the audio and video source input connections as well as the power amplification section and outputs for all the HT speakers. The only component most of these units dont have is an internal AM/FM tuner, but it will have inputs for a seperate tuner box if you want one. You would hook up all of your devices to this one box and wire your speakers to it also.
I hope this helps a little in a nutshell. Let me know how else I might be able to help.
Kevin Usleman- ADCAV--Advanced Custom AV Technologies
Cincinnati

 

[Kevin U]

Hello again Richard,
After posting my first reply, I went and visited the Denon site to see just what what the 2802 was.
My conclusion is that you dont need a seperate amp, as your Denon unit is a 6.1 Dolby Digital audio and video reciever (hence the AVR designation) that has the power amplification you need to drive 6 speakers (2 front mains, 2 rear surrounds, a front center channel and a rear center channel) with 90 watts per channel of power, and a subwoofer , as well as inputs for most any other audio and video source you may want.
If you are asking how to drive just your 2 front main speakers seperatley, they will be driven by any stereo input source component (CD player, Tape player, stereo VCRs, phono, amfm tuner) you may hook to the AVR 2802. You will need no other component to accomplish this. The other speakers will only be driven by the sources that have multichannel capabilities (which is probably your DVD player, Laser disc player and your Satelite or cable box from channels that broadcast dolby digital sound), or maybe the Denon has simulated multichannel settings that would send simulated sounds to the other speakers. You would need to experiment with these simulated settings to see if you like them.
Now is it clear as mud?? I think you are ok with what you have.
Let me know if you have any other questions.
Again, Regards,
Kevin Usleman
ADCAV- Advanced Custom AV Technologies

 

[Saurav]

$2000) obviously a Processor does much more than I think. How do they differ from your typical multichannel HT receiver?

They only do the processing, they don't have the power amps that a receiver has, so you need to hook them up to power amps to drive speakers. A processor is similar to a preamp, except it handles 5.1 digital audio and maybe video too, instead of just analog audio like preamps. Why do they cost more? Probably because they use better designs and parts so that they sound better. In terms of 'block diagrams' though, a receiver contains both the preamp/processor part and the power amp part.
Hope that helps.

 

[Richard Harvey]

Yep, I know what my 2802 can do, and it does it great! I'm just trying to follow all these other discussions here of people who take what would seem to be very strong A/V receivers (like a Denon 4802), then add separate power amps to drive the mains, center, and surrounds independently (basically, the 4802 becomes nothing but a 5.1,6.1,or 7.1 processor, but nothing else).

Given that, I've heard that for music purposes have a dedicated stereo amp could be a "step up" for my purposes (since my stereo is rated to 90W/channel, but my mains are rated to 250W per speaker). But, my confusion came down to what "device" am I looking for: preamp, stereo amp, power amp, monoblock, etc? There are so many terms, and sometimes it's not clear on why you would choose one over the other (yet the mags seem to imply that everyone should just know this stuff off the cuff).

So, if I'm understanding everyone here:
- I already have a "processor" with my 2802, since it handles 5.1 and matrixed 6.1 formats
- I already have a preamp, since my 2802 already has inputs for independent devices and provides services like tone controls (which I disable on purpose)
- I already have a tuner, since my 2802 "receiver" has that functionality built-in
- I already have a power amp, which can drive 6 channels.

What I don't have, but could add, is either 2 monoblocks or a stereo amp to power my mains for supposedly better 2-channel music reproduction. Does this sound correct? If so, what are some typical brands and reasonable price ranges? From many I've seen, they don't run much higher wattage than my 2802, and I know it takes a doubling of wattage to gain 3db, so is it simply better "build" quality that makes a dedicated amp better, or simply that you don't clip or lose "umph" in key scenes when a unified receiver might be taxed on all channels?

Rich

 

[John Garcia]

From many I've seen, they don't run much higher wattage than my 2802, and I know it takes a doubling of wattage to gain 3db, so is it simply better "build" quality that makes a dedicated amp better, or simply that you don't clip or lose "umph" in key scenes when a unified receiver might be taxed on all channels?

Any decent external amp with the same wpc rating, or even less, will almost certainly outperform the amps in your receiver. YES build quality, as well as the fact that a dedicated amp is supplying basically all of it's power only to amplification, makes a comparison of power between an integrated and separate amp not exactly a linear case. Monoblocks go a step further - as each channel is not sharing power with any others (this may also be the case with some multi-channel amps).

What speakers are we talking about and what is the room size?

 

[Richard Harvey]

They are the Infinity RS-5 reference towers. My room is about 18' x 20' x 12'. Movies seem fine, but music CD's don't have much "kick" to them. I'm not sure if that is due to the Denon, the speakers, the room size, or a combination.

Rich

 

[Saurav]

It could be the amps in the receiver not having enough juice, it could be the preamp in the receiver not having the kind of sound you like. It could also be that you just don't enjoy the sound of your speakers when you're really paying attention to them (i.e. listening to music) vs. not paying as much attention (watching a movie). The same can be said for your CD/DVD player that you use as a source.

In short, it could be any number of things. I would advise trying out gear in your system before you commit any money, as your dissatisfaction could be due to several causes.

Edit: For starters, have you experimented with speaker position? The optimum position for speakers is often several feet into the room and fairly unacceptable aesthetically. There are online articles discussing how to place your speakers, try those out for starters. It's free, and you might be amazed at how much your sound improves.