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Why are preamps so important?


vman71

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The more I read, the more I get the impression that a preamp plays a vital part in how good/bad a system sounds. Why is it so important?

They are the primary control and signal processing hubs of the system.

Inerfaces, signal/protocol conversion, level matching... you name it...and how many I/O formats are you dealing with? With the added complexity, comes greater variability.

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"They are the primary control and signal processing hubs of the system.

Inerfaces,
signal/protocol conversion, level matching... you name it...and how
many I/O formats are you dealing with? With the added complexity,
comes greater variability."

Um yeah .. what he said.. LOL

Basically, anything from the source be it a CD, iPod, Cable HDTV, etc., has to be sent through or processed and then sent to your amp.

In this case "Garbage In" gets re distibuted as "Garbage Out"!

I might even argue a Pre Amp is MORE important than your amp.

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The idea is that the closer you are to the source of the music, the more important the component becomes. So the disc player is extremely important, than the pre-amp and so forth down the chain. However, I don’t agree with the general “front–end of the chain is most important” argument. Although a chain is only as strong as its weakest link, the link you are holding is the one that matters most to you. I think the link next to the ears is the mort important. Mainly because loudspeakers are the only bargain in audio - even well made inexpensive ones give an amazing rendition of the actual event for the money, they are the best bang for your buck. You start with big ole horns for the best value in sound and work back from there.
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I suppose the replies should be taken in the context of
whether or not your preamp will be acting as an audio / video converter or just
a switcher / volume adjustment.





Source units have different types of outputs... from variable volume analog to pure digital
data.... I suppose what signal you are
feeding it will determine it's importance in your audio chain?

ROb

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true rob,,,,

There is always the audio purist too....

Most people that have never heard a Cello up close with someone really good at it have missed out. To get that dynamic experience from someone who can play it like Yo Yo Ma through K horns is Wonderful.... but still a 2nd, to it live.

Here is a great listen for you to enjoy!

Bach's "Cello Suite No.1" by Yo-Yo Ma, accompanied by a Salvador Dali-inspired slideshow.

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I don't use a preamp in my #1 system, just a passively-attenuated remote-controlled volume device (Creek OBH-10).

I miss not having a balance control because my seating position is a little off center, but I can always move the couch when I'm doing serious listening.

Sometimes I miss not having tone controls, but I have issues with what they do to the sound quality of my system, so it's a tradeoff that most of the time I'm willing to make.

I never thought I'd become an audiophile, but it happened.

Greg

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The more I read, the more I get the impression that a preamp plays a vital part in how good/bad a system sounds. Why is it so important?

=================

The entire CHAIN of A-F from that tiny source signal to your loudspeaker cones is ALL IMPORTANT. All of these steps are amplifiers in the generic sense, and they are simply sprinkled into boxes for various convenient purpose.

That's very much the way I see it as well. While I have more than one digital source it's still not enough in my opinion to warrant a complete overhaul of my current configuration.

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I've always advocated that IF you intend to use a preamp, then use complimentary or like components.

As posted earlier, the weakest link will always be your downfall. Hence, when I purchased my Yamaha equipment, they were a good compliment of technology that was available in the early 80's. It was all I could afford for separates at the time.

With a RTR, TT, CD player, Cassette unit, Tuner, and peripheral devices (EQ/DBX - looped), I required a very flexible piece of equipment with multiple inputs/outputs.

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Several years ago I picked up a Adcom SLC (straight Line Controller) for about $50. Basically, it is a switch and a 12K Ohm pot (conventionally wired). These are sometimes called "passive preamps". I have never looked back.

There are caveats. The impedances must be appropriate (low output Z on the source and high input Z on the amp) and the cabling should be short and have a low capacitance (and No, this does not mean "fancy" cable). Of course it requires line level sources (no phono).

There is something to be said for fewer components in the chain (talk about "neutral" sounding ...)

Good Luck,

-Tom

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I would say it is no more or less important that any other stage in the signal path. OTOH, there is no reason to think a given pre amp has been designed any better or worse than any other stage in the signal path.

There is the preported oriental story. A man is on his hands and knees in a room. A friend comes in ask what he's doing. A: "Looking for a coin I dropped on the other end of the room." Q: "So why are you looking on this end?" A: "Because the light is better here." Ergo, people examine pre amps mostly because it is easy to do so.

- - -

Pre amps do serve as a control center. In the old days they had a rather modest gain stage and switches, and the tone controls, and the phono cart amp and equalizers. Now they are digital signal processing computers, depending on what you've got.

In the old times or new, we have to keep in perspective just what is in the signal path chain from recording microphone to the speaker. There are many stages and we have control over very few if we just look at the home pre amp. It is probably fair to say that there are dozens of stages in the chain.

As stated by others, any weak link is bad. Distortion may be added. Not good. But a good pre amp, or any link can not remove it.

Overall, I can see replacing a poorly performing pre amp. But, is there really any reason to think there is a problem caused by the pre amp? And to repeat my bromide, you can't make things better by solving a problem which doesn't exist.

Gil

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Tom,

"Several years ago I picked up a Adcom SLC (straight Line Controller)
for about $50. Basically, it is a switch and a 12K Ohm pot
(conventionally wired). These are sometimes called "passive preamps".
I have never looked back."

Yup, I used one of them for a few years way back when too, nice unit. Another really good buy (more solid feeling then the SLC.. I replaced the SLC with one) is the Mod Squad Line Drive. I see them go for around $200-$300 depending upon if it is a Deluxe version or not. That later became the McCormack TLC which is another nice passive which also had a buffered output for sources that had problems driving a passive. I had the SLC/Line Drive Deluxe paired up with a Curcio Audio DAC which put out over 4v so it handled the passive easily.

Shawn

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As others have said if you only have one line source with volume control then it probably isn't all that essential - assuming a normal line source with sufficent output to drive the amp at the volume you want.

If neither your source nor your amp has a volume control - and/or if you have multiple sources then you do need some means of controlling the system.

A passive pre-amp is exactly this - it allows you to switch between 2 or more sources and it allows you to adjust the volume.

A passive pre-amp is probably the most transparent (or should be) item you can put into the system whilst retaining the above functionality.

An active pre-amp is often not transparent - and adds "flavour" to the system. People choose different technologies of active pre-amp to get the sound they want - be they SS, tube or digital. Digital pre-amps are often bundled with signal processors that translate digital inputs into forms suitable for the installed amp (maybe analogue - maybe another digital format). The latter also often contain various options for adjusting the sound with built in settings (Hall, Cinema etc. etc.) that seek to mimic the sound you might hear in these venues. These are implemented with varying degrees of success.

Aside from these functions many pre-amps have facilities for adjusting the amplificiation including such things as balance, bass, treble and even mids volume and so on. Some even incorporate equalizers of various forms.

Whilst it could be easy to surmize that a pre-amp adjusting the nature of the sound (adding flavour|) is probably not a good thing this is not always the case. If there is an input impedance mismatch between source and amp a pre-amp may well serve to overcome this issue and hence improve the sonic result.

Matching your amp (assuming it is not integrated) to a pre-amp can yield a striking effect on the sound. A combo of amp and pre-amp can produce a more acceptable sound than merely going from source to amp - of course it may not - that is for the individual listener to decide.

It is also worth mentioning that a pre-amp can be used to ameliorate the sound coming from a poor source. It is not a fix of course - but you might find the original mix has, for example, too strong a bass for your enjoyment so you can make an adjustment for that particulare recording.

Conversely if you listen at low volume levels you might find that a function such as "bass boost" is useful to get more of an impression of the sound at higher volumes.

In a nutshell then, pre-amps are simply useful for a variety of applications. Whether it is better to have a separate one or one integrated into one of the other components in the system is, as ever, a matter for the individual owner of the system.

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