jjhaz@ont.com Posted February 23, 2002 Share Posted February 23, 2002 Ok I know its a stupid question on the surface. We all know that preamps control volume, balance, tone and source. Why do many exotic preamps have elaborate voltage regulation, tubes, all kinds of hi tech schemes only to top it off with the ability to Bypass everything but the volume for the true purist audiophile. Why dont we simply hook up our CD players directly to our power amps? I know turntables need a preamp but why line level components? What does the preamp do to enhance the sound of our sources? Jeff ------------------ Home Theater Room Cornwalls Main fronts ALK Networks Heresy Center run parallel with KLF-C7 Center IW-150 Rears KSW-12 200watt Sub (na) Anthem AVM20 Preamp 5 Adcom 555s Modified By Musical designs all mono Block Toshiba 9200 DVD Echostar 5100 DD Satellite Listening Room Cornwalls (not modified yet) Antique Sound Labs Integrated Tube Amp Rotel RCD 991 Quote Link to comment Share on other sites More sharing options...
Underhanded Penguin Posted February 23, 2002 Share Posted February 23, 2002 Somebody please reply to this thread. I don't understand why either. -UP ------------------ Liv Tyler as Arwen: "If you want him, come and claim him!" - Translation: "I am very hot." Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 23, 2002 Share Posted February 23, 2002 Well, If you hook up a CD player with no volume control(Fixed output)into a power amp with no volume control, you better hit the dirt when you turn it on. A fixed output puts out a constant line level at the fixed level. You have to have some sort of attentuation somewhere. Quote Link to comment Share on other sites More sharing options...
Deang Posted February 23, 2002 Share Posted February 23, 2002 I think it's simply because a preamp is responsible for elevating the low level source signals before they go to the amp. I'm left with the idea that this is an important step in capturing the whole of the original signal. I've read many comments by people using simple passive devices and not really being happy with the sound. They describe the sound as 'lifeless' and 'flat'. Others claim that a properly well designed passive device reproduces without these ill effects. My 'whimpy' explanation will have to hold you over until the heavyweights show up ------------------ deanG Quote Link to comment Share on other sites More sharing options...
jjhaz@ont.com Posted February 23, 2002 Author Share Posted February 23, 2002 It sounds like if we set aside the convenience of source switching and the necessity of volume control, the real function of the preamp is to regulate voltage and impedance. Is that right? Jeff ------------------ Home Theater Room Cornwalls Main fronts ALK Networks Heresy Center run parallel with KLF-C7 Center IW-150 Rears KSW-12 200watt Sub (na) Anthem AVM20 Preamp 5 Adcom 555s Modified By Musical designs all mono Block Toshiba 9200 DVD Echostar 5100 DD Satellite Listening Room Cornwalls (not modified yet) Antique Sound Labs Integrated Tube Amp Rotel RCD 991 Quote Link to comment Share on other sites More sharing options...
Malcolm Posted February 23, 2002 Share Posted February 23, 2002 I have run without a preamp from time to time as a matter of convenience or necessity, using nothing more than the volume control on the source, but only for those reasons. A preamp, or the corresponding circuitry in an integrated amp, is a signal processor. Among other things, it lets you tailor the sound to the environment and listener. The bypass/flat switch is there so you can easily switch between the flat signal and your tweaked signal so you can hear the difference. There are, indeed, those who always run with the bypass/flat switch on. There even some who eschew a preamp with active elements in favor of a passive "preamp" that does nothing more than insert a variable resistance between the source and the poweramp. The theory is that the less you do to the signal, the more accurate the resulting sound will be. OTOH some people who have tried a passive "preamp" find them to sound flat/compressed/lifeless. IMHO, passing the signal, flat, unmodified directly from the source to the power amp is going to result in less than optimal sound in almost every case than a signal that has been tweaked for the environment with even rudimentary tone controls. This is because, even assuming a perfect source and power amplifier, the speakers, room and listener's ears are going to ensure that what is heard is not the same as what was intended by the engineer who mastered the recording. If you want to hear the shortcomings of your equipment and environment, by all means, turn the bypass switch on. If you want the most accurate sound, or even the most personally pleasing sound, you are going to need to tweak the signal. And in most cases, for the most accurate sound, you will need more signal conditioning that even your preamp can provide to do the job right. Quote Link to comment Share on other sites More sharing options...
rowooo Posted February 23, 2002 Share Posted February 23, 2002 jjhaz....I've tried both methods and on my system I think it sounds better with the preamp. Don't know why and just does. Plus my C.D. player with volume control just didn't have enough gain. I bypass everything on my Preamp too. Explanations please!!! Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 23, 2002 Share Posted February 23, 2002 Yup. I always use the Tone Controls on my Pre. The treble is always set at 0 (Flat), with the bass nudged up to about 2 or 3 o'clock. Otherwise, the mid and highs seem to dominate. Low gain with some CD player volume controls is form impedance matching problems, I would guess. Not enough output gain to match the input gain. Good posts, BTW. I think folks can get a idea about what pre-amps are all about, from the replies. THANX! This message has been edited by mike stehr on 02-23-2002 at 11:30 PM Quote Link to comment Share on other sites More sharing options...
jjhaz@ont.com Posted February 23, 2002 Author Share Posted February 23, 2002 Ok so we all seem to agree that out music sounds better with a preamp. I agree. This question came up because I was comparing a new Antique Sounds Lab integrated amp against one of my modified Adcom amps. In this second room I didnt have another preamp. I hooked up my Rotel CD to the ASL amp; the ASL has no balance control, no tone controls, just 3 input selects and a volume control. I hooked up an older HK 380 CD player with a volume control to my Adcom and just switched the Cornwalls back and forth. I know my Adcoms sound great in my main system but there I have a Sonic Frontiers Anthem AVM20 preamp. So the whole question came up in my mind (as small as it is) what was the preamp contributing. I always listen to my system with the tones flat, although I dont begrudge anyone the right to tweak their sound however they like. The Anthem is also a processor but I can and do bypass the DAC and tone system when ever Im listening to music. I agree with mdeneen and others in this thread that voltage regulation in all its forms must be the key to the preamps sound function. Jeff ------------------ Home Theater Room Cornwalls Main fronts ALK Networks Heresy Center run parallel with KLF-C7 Center IW-150 Rears KSW-12 200watt Sub (na) Anthem AVM20 Preamp 5 Adcom 555s Modified By Musical designs all mono Block Toshiba 9200 DVD Echostar 5100 DD Satellite Listening Room Cornwalls (not modified yet) Antique Sound Labs Integrated Tube Amp Rotel RCD 991 Quote Link to comment Share on other sites More sharing options...
TheEAR Posted February 23, 2002 Share Posted February 23, 2002 "What does the preamp do to enhance the sound of our sources?" Ah for example I use a solid state amp with tube preamp,this gives me a good measure of the tube magic many seek and the savage punch of solid state amps. In other words its the best of both worlds. The preamp often with add its own sonic signature,many times positive(in the case of tube preamps).Its like so many noticed a gain controll and source selector. As I dont have any tone controls on my preamps and will never buy a preamp with tone controls.The purest path is paramount. Just my two cents TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
jjhaz@ont.com Posted February 23, 2002 Author Share Posted February 23, 2002 mdeneen, Thanks for that last explanation. Your answer makes perfect sense. Jeff ------------------ Home Theater Room Cornwalls Main fronts ALK Networks Heresy Center run parallel with KLF-C7 Center IW-150 Rears KSW-12 200watt Sub (na) Anthem AVM20 Preamp 5 Adcom 555s Modified By Musical designs all mono Block Toshiba 9200 DVD Echostar 5100 DD Satellite Listening Room Cornwalls (not modified yet) Antique Sound Labs Integrated Tube Amp Rotel RCD 991 Quote Link to comment Share on other sites More sharing options...
Deang Posted February 23, 2002 Share Posted February 23, 2002 mdeneen said - "When you simply place a Volume Control pot (passive preamp) in the circuit, you have created an uncontrolled R-C filter, where the pot is the resistance, and the cable is the capacitance. If the resistance is high, you will get a high end rolloff, if the resistance is low, you will distort the source feeding it" This is interesting and yet makes me ask why so many integrated amps do just exactlty that - like Jolida and Creek Audio. The AE-25 Superamp I'm getting this week has a volume control. Strange. ------------------ deanG Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 24, 2002 Share Posted February 24, 2002 There is line stages using tranformers by the way. Quote Link to comment Share on other sites More sharing options...
kenratboy Posted February 24, 2002 Share Posted February 24, 2002 quote: Well, If you hook up a CD player with no volume control(Fixed output)into a power amp with no volume control, you better hit the dirt when you turn it on. LOL!!! Thats funny, I should try it. Sereously, is a preamp at maximum volume the same as the LINE OUT from a component without adjustment? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 24, 2002 Share Posted February 24, 2002 It really depends on the output of the source unit. It could be loud, it might not be. But you won't have any way to turn it up or down, It's a fixed level. Quote Link to comment Share on other sites More sharing options...
Deang Posted February 24, 2002 Share Posted February 24, 2002 Here is the response from the fellow who just sold me the Superamp regarding the volume control. "I wanted to be able to drive the amp either from a preamp or via direct from cd input. Because there is only one set of inputs on the amp and because I needed to control line levels when connected directly, the volume control was installed. It is a passive control that operates on the input jacks and allows you to control the levels when driving direct from the cd's inputs. Or, by maxing out the volume control on the amp, you can drive it via a preamp and let the preamp control levels. All of the burn in time was done via the direct cd to amp configuration which minimizes the level of coloration that gets introduced (my opinion)." What he is describing here is 'unbuffered' then - right? ------------------ deanG Quote Link to comment Share on other sites More sharing options...
Deang Posted February 25, 2002 Share Posted February 25, 2002 hmmm - so besides the additional switching functions - what would the addition of an AE-3 really get me? ------------------ deanG Quote Link to comment Share on other sites More sharing options...
Deang Posted February 25, 2002 Share Posted February 25, 2002 guess I'll be enjoying the simpler system thanks for the education mdeneen! ------------------ deanG Quote Link to comment Share on other sites More sharing options...
Barista Posted February 25, 2002 Share Posted February 25, 2002 Man, great posts! Good information! All this got me to thinking. I'm no electronic whiz, but I LOVE to tinker, and I know enough to play around. Given the above sentiments are true, then..... Why couldn't someone build a nice passive pre-amp with a quality volume pot, and experiment with various electrical components (Caps, resistors) to achieve a customized EQ for their specific speaker/room situation. It would be kinda neat if you had a little box with a vol pot and the ability to insert components inline to taylor your signal. Might be a fun learning project, and based off what everyone here has said, it would be the most accurate, closed path (Given you had good components). Also, my dad gave me a stereo "L-Pad" that I use to attenuate the volume of my outside patio speakers, is this the same thing as a passive volume pot that we are speaking of? ------------------ Barista T. Bill My Rig, Minus the new Klipsch RF-5 (Not shown) Quote Link to comment Share on other sites More sharing options...
Barista Posted February 25, 2002 Share Posted February 25, 2002 Hmm, another question just came to me.... What's to say that the only reason Pre-Amp(A) might sound better than Pre-Amp( is because Pre-Amp(A) has some passive EQing built in? (A) might be $200 more than ( simply because it has better signal EQing apposed to ( being totally flat? ------------------ Barista T. Bill My Rig, Minus the new Klipsch RF-5 (Not shown) Quote Link to comment Share on other sites More sharing options...
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