Preamplifers, Processors, and Power Amplifiers - What are their importance? (1 Viewer)

[Chris Bozeman]

I've spent the past day or so pouring over the knowledge contained in these forums and I read the home theater primer post, but the explanation doesn't exactly flesh out the why I need these things as part of my home theater.

Right now due to the space constraints of living in the barracks here on base at Pearl Harbor, I purchased a Sony HT-6600 DP Home-Theater-In-A-Box kit because I really don't have space for anything else at the moment; however, when I move out into the surrounding city area of Aiea or Honolulu into my new home, I will be looking at renovating a room for a grandiose home theater setup, so I feel its important for me to get a good foundation on the intricacies of home theater design in regards to sound reproduction. I feel I've got a pretty good handle on display technologies for the most part, but this is one area in which I feel I am lacking the breadth of knowledge that I want, so...

Anyone that can provide a reference to another post, a link to another web site, or just an explanation as to what exactly these things do and why they are necessary given today's receivers, I would greatly appreciate it.

 

[Vince Maskeeper]

Mentioned in FAQ and primer.

The main advatages are seperate power sources (better for power amps to have dedicated power supplies) and better ability for upgrade paths (when you want more power you need only swap out the amps- or if you like your amp sound, you can swap out a preamp unit when new audio formats come along).

 

[Bob McElfresh]

Hi Chris.

A modern AV receiver is 2 devices in 1 box:

- A pre-processor
- A 5-channel amplifier

The PreProcessor does a LOT of things:

- Takes a digital signal and decodes it into 6 analog signals. This can be PCM (from a CD) or Dolby Digital, DTS, or DolbyProLogic2 encoded signals.
- Performs "Bass Management" to route low-frequency sounds below about 100 hz to a external subwoofer if equipped.
- Performs "Bass Management" to route low-frequency signals from a "small" speaker to the nearest LARGE speaker.
- Performs switching so you can have a CD player, DVD player, VCR, Sat receiver, all hooked up and switch from one to the ohter at the touch of a button.
- Can detect you dont have a center or rear speakers and route sounds intended for these to your L/R speakers
- Etc.

So the pre-processor does all the electronic decoding & fancy stuff.

The amplifier - takes a line-level (un-powered) music/voice signal and increases the power so it can drive a motor (your speakers).


You can buy "Seperates": a small box that does all the pre-processing, then mix/match external amplifiers. You can buy 5 Mono-Block amps, a 3 channel amp for the front 3 speakers and another, lower-power 3 channel amp for the rears, etc.

Seperates give you more things to play with. But the cost is a bit more plus there is extra cabling.

You CAN have both: Buy a good AV receiver with pre-outs (6 RCA jacks). Start with this, but later you can buy external amplifiers and feed them from the pre-outs. This gives you a pre-processor/amplifier system later on.

Hope this helps.

 

[Chris Bozeman]

Thanks so much for the explanation Bob... it really cleared up a lot of things for me!

 

[Jack Briggs]

Chris, off-topic here and just curious: Since you're stationed on base presently, what kind of display/monitor are you using in those cramped barracks?

 

[Chris Bozeman]

Right now its nothing special, just a Sony FD Trinitron 32" model - the exact model number escapes me, but it was the cheapest entry level model available at the Navy Exchange when I arrived here on the island. It was around $530, but it had component video inputs, which is the main reason I purchased it... I just wanted something relatively sizable to hold me over until I got moved into a home. It works considering this entire room is only 8' by 10'... :

 

[Jack Briggs]

Wow, Chris, I bet that WEGA takes up some space in those quarters. You are aware that it has a 16:9 mode?

 

[Chris Bozeman]

Indeed I am... I've thoroughly explored the options menus and read through the manuals for all the equipment I have, and that includes computer equipment as well. One of my first jobs in high school was working technical support for Gateway through a subsidized call center, and what I noticed more than anything is that if users would spend the time to read manuals, FAQs, and the other assorted information provided to them, they could answer most of their own questions; as a result, I thoroughly read through the manuals for everything I buy so I understand everything about it.

However... now that you've piqued my interest into this feature, I'm watching Die Hard 5 Star Collection which is 2.35:1 and I have 16:9 Enhanced Mode turned ON, and the only thing it seems to do is squish the picture vertically... I assume this is to represent the movie more accurately? As it would be displayed in the theater?

 

[Nathan Stohler]

Chris,

You must also set your DVD player to output in 16:9. Otherwise, your picture will be distorted (squished).

In other words, 16:9 Enhanced ON (on your Vega) + 16:9 output on your DVD player should give you roughly the same sized image as 16:9 Enhanced OFF + 4:3 mode on your DVD player.

--Nathan

 

[Jeff Gatie]

Chris, read the Primer entry under "Anamorphic Enhancement" for an explanation of enhanced for 16:9. Basically, it shows a widescreen picture at it's original aspect ration, but it takes advantage of the anamorphic image, giving you 1/3 more lines of resolution which results in a far superior picture quality.