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Amp vs. Preamp vs. receiver vs. DAC?

post #1 of 8
Thread Starter 
I've been on a question asking storm lately, apologize to anyone that may annoy--just trying to build up my knowledge base. Can someone please explain to me what exactly the uses, applications, and differences are between an Amp, preamp, receiver, and DAC (which I'm guessing to be digital-to-analog convervter?)? Thanks kindly.
post #2 of 8
let's go along the chain :

DAC : it converts the raw digital signal extracted from a cd to an analog signal, usable by the analog components following (preamp, amp, speakers). Usually, it outputs a fixed and weak signal of 2V.

Preamp : it's the control unit of a system. Basically, it's a volume control and an inputs/outputs selector. In some case, it also incorporates a phono preamp (the signal coming from a turntable is very weak and need further amplification before being usable; it's also in need of some tonal adjustments). Finally, a preamp can be active or passive : a passive preamp is just a volume control and a few switches, it just attenuates the signal. The signal coming out of it can only be 1 or under. An active preamp puts the volume control between gain stages, in order to present a stronger signal to the amplifier and ease the pressure on the output stage of the dac and input stage of the amplifier. It also cures some impedance mismatches.

Amplifier : it's what gives actually power to your speakers. The weak signal of the DAC isn't sufficient to move the magnets of your speakers (it's in the order of a fraction of a W). The amplifier scales up the signal.

An integrated amplifier is a box with both a preamp and an amplifier.

A receiver was initially an integrated amplifier combined with a tuner. Today, it is mostly used for an integrated amplifier combined with a digital surround processor, used for home theater application. They often have more than 2 channels of amplification.
post #3 of 8
Thread Starter 
So why do some preamps have headphone outs on them? Shouldn't they only be used to adjust equalization? Also, what is a DAC ever used for? I understand the digital to analog business, but I'm confused in application of--both, really.
post #4 of 8
Quote:
So why do some preamps have headphone outs on them? Shouldn't they only be used to adjust equalization? Also, what is a DAC ever used for? I understand the digital to analog business, but I'm confused in application of--both, really.
I think headphone jacks are included in preamps, because it's a desired feature. I don't think it adds much to the cost to add a simple jack/amplifier connection, and you can use the input selector, gain control, power supply etc. for the headphone circuit too. Note I said it doesn't add much to add a "simple" one - a good one may be a different story. I suspect that good headphone circuits being widespread in mass consumer electronics probably stopped happening with the advent of electronic receivers in the early 80's (integrated circuits vs. discrete components). So, your old silver 25 lb. pioneer receiver probably has a better headphone circuit than your sleek black receiver you bought 10 years ago. [this is all wildly generalized, of course - there are definitely exceptions] Preamps are somewhat of a different story, since they tend to be higher end products in the first place. In fact, I have a nice preamp in storage (Bryston) that I need to dust off and try its headphone section. It could very well be exceptionally good.

RE: DAC's - not sure exactly what your question is. Most people will have a component DAC in their system if they feel that the one they have been using is a weak link in the audio chain. For example, many modern receivers/preamps have built-in DAC's for decoding the digital stream from an outboard DVD or CD player (via Coaxial RCA digital or Toslink optical). However, these on-board DAC's are not necessarily the last word in sound quality. Therefore, people add a DAC component to get better performance. The output from the DAC is in the form of RCA analog output, generally. You can take that output, and use it as input to your home stereo, your headphone amplifier etc. When technology changes in DAC's you can sell it to a person less obsessed with audio and upgrade without touching the rest of your system.

This is probably way more than you wanted to hear from me, but once I get on a roll, it's hard to stop.
post #5 of 8
I'm new to all this, i was wondering what would be the most worth it thing to buy, a 75$ Cmoy with bass boost Bass Boost cMoy v2.02 Amp - Premium Headphone Amplifier on eBay (end time 06-Dec-09 00:34:01 GMT)

or a headroom total bithead, one being just an amp and the other an amp + dac. I am currently using audio technicas ad700.
post #6 of 8
Oh no a necromancer. I'm outta here.
post #7 of 8
I'm trying to set up a vintage Pioneer sx1010 to play digital files. It is not listed as intergrated amp but is a receiver does that mean it has a preamp? I would like to set it up so I don't have to tie up the lap top. Could some one send me some ideas for managing the files dac issues and display the info of what's playing. Basically we are trying to relive our nostalia sounds when our wives sent us to the shop. Like crank it up while working on antique cars boats and of road toys like a TomCar. The sx1010 is original owner with the original KLH speakers bought the same day. Setting it up in shop office with set up to put all the old vinyl on digital files. Have old monitor and outdated computers want to make play list for the day on a screen. SHOULD BE A ROCKING GOOD TIME that's the point of all this audio love.
post #8 of 8
I'm trying to set up a vintage Pioneer sx1010 to play digital files. It is not listed as intergrated amp but is a receiver does that mean it has a preamp? I would like to set it up so I don't have to tie up the lap top. Could some one send me some ideas for managing the files dac issues and display the info of what's playing. Basically we are trying to relive our nostalia sounds when our wives sent us to the shop. Like crank it up while working on antique cars boats and of road toys like a TomCar. The sx1010 is original owner with the original KLH speakers bought the same day. Setting it up in shop office with set up to put all the old vinyl on digital files. Have old monitor and outdated computers want to make play list for the day on a screen. SHOULD BE A ROCKING GOOD TIME that's the point of all this audio love.
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