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Importance of preamp in a system

insider9

Well-known member
Sep 20, 2016
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Hi all,
I'll start from some background. A couple of weeks ago I got a Yamaha WXC-50 mainly as a steamer/flac player/dac. I usually listen on the same volume setting so don't use it in streamer mode bypassing preamp.

My Primare integrated doesn't have tone controls or anything fancy. In fact in the way of a preamp phase it only has a volume knob.

It gave me an idea. Since owning a Yamaha I could potentially get a power amp instead of another integrated in the future. Yamaha's got enough inputs for my needs. I would only rely on volume as not interested in eq.

So here a question. Is a power amp section that's mostly responsible for sound quality? If so would a Yamaha as pre + power amp produce potentially better sound than Yamaha + integrated amp?

Reason I'm asking is I've noticed that usually you can get a better quality power amp compared to same cost integrated. Or simply same quality power amp will cost slightly less than integrated.

Also are the well matched pre + power important (implying that the pre stage is more important than I think)?

Sorry if this is obvious to some of you but I appreciate if you take your time to reply. Thanks
 

nopiano

Well-known member
Feb 15, 2009
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It is unlikely that there is an universal answer, but I'd suggest the preamp is the section more likely to affect tonality and detail - resolution if you like. The power amp, however is more about the mechanics of driving and controlling the speakers. How quickly the drive units stop, start and change direction, if you like a driving analogy. Don't underestimate the importance of the preamp though (and read up on passive ones another day!)

The slightly more mysterious yet sometimes articulated aspect of a preamp is how well it drives the power amp, which technically I suspect is a matter of impedance matching, and operationally more about how well matched the volume control range is - if you like, either too loud or too quiet. I'm sure there are cases where a pre is a bit warm and the power and bit lean, or vice versa. That would make them more suited as a pair and less interchangeable.

Lastly I'd add that rarely is mixing and matching a great idea, unless recommended by a dealer or importer. I'm thinking about Audio Research tube preamp with Krell power amps a few years ago, as a popular choice.
 

insider9

Well-known member
Sep 20, 2016
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nopiano said:
It is unlikely that there is an universal answer, but I'd suggest the preamp is the section more likely to affect tonality and detail - resolution if you like.  The power amp, however is more about the mechanics of driving and controlling the speakers.  How quickly the drive units stop, start and change direction, if you like a driving analogy.  Don't underestimate the importance of the preamp though (and read up on passive ones another day!)

The slightly more mysterious yet sometimes articulated aspect of a preamp is how well it drives the power amp, which technically I suspect is a matter of impedance matching, and operationally more about how well matched the volume control range is - if you like, either too loud or too quiet.  I'm sure there are cases where a pre is a bit warm and the power and bit lean, or vice versa.  That would make them more suited as a pair and less interchangeable. 

Lastly I'd add that rarely is mixing and matching a great idea, unless recommended by a dealer or importer.  I'm thinking about Audio Research tube preamp with  Krell power amps a few years ago, as a popular choice. 
It does make a lot more sense if you put it that way. It further reaffirms why people go pre+power route.

Thanks Nopiano for great answer.
 

davedotco

New member
Apr 24, 2013
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insider9 said:
nopiano said:
It is unlikely that there is an universal answer, but I'd suggest the preamp is the section more likely to affect tonality and detail - resolution if you like. The power amp, however is more about the mechanics of driving and controlling the speakers. How quickly the drive units stop, start and change direction, if you like a driving analogy. Don't underestimate the importance of the preamp though (and read up on passive ones another day!)

The slightly more mysterious yet sometimes articulated aspect of a preamp is how well it drives the power amp, which technically I suspect is a matter of impedance matching, and operationally more about how well matched the volume control range is - if you like, either too loud or too quiet. I'm sure there are cases where a pre is a bit warm and the power and bit lean, or vice versa. That would make them more suited as a pair and less interchangeable.

Lastly I'd add that rarely is mixing and matching a great idea, unless recommended by a dealer or importer. I'm thinking about Audio Research tube preamp with Krell power amps a few years ago, as a popular choice.
It does make a lot more sense if you put it that way. It further reaffirms why people go pre+power route.

Thanks Nopiano for great answer.
Back in the day pre-amps were far more complex beasts than today, often focusing very heavily on the phono stage and required to give significantly more gain to inputs from tuners, tape machines etc, that typically had around 1/10th of the output of modern day digital players/processors.

Modern pre-amps, whether as part of an integrated amp or stand alone are far simpler and unless deliberately designed to 'voice' the sound, by using valves perhaps, they are less important. Passive pre-amps, essentially a volume control in a box (with or without input switching) work because the high 2volt+ output of digital sources is more than enough to drive post power amps direct.

The minimalist approach has its advantages but needs a little thought regarding impedance matching. They can be a good match with valve power amps which tend to have very high input impedance, hence being less bothered by the variations in source impedance from a source/passive pre-amp combo.
 

NSA_watch_my_toilet

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Aug 24, 2013
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In my hifi gear collection, I have a reknowned passive hifi preamp of rotel.



... it makes not a lot of sound by himself. So does different preamps. But, as an other member said, even if a majority of preamps are completely transparent and just amplify an incoming basic volume, some could bring colours.

After that, you have, now, CD players and DAC that can be directly connected to power amplifiers. This is possible. I don't know what is required to doing this, but it's possible.
 

Rethep

Well-known member
May 2, 2011
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I only use a (valve) power amp with a volume pot, since i only use Airport Express output. Combined with beautiful speakers, the excellent sound keeps me from looking for improvement, for 3 years now already!

So the answer: no, you don't need a pre-amp if you don't use a record player! The less (electronics/wires) there is between input and output, the better.
 

andyjm

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Jul 20, 2012
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These days, with source devices (streamers, DACs, CD players etc) all having line level outputs, a pre-amp is effectively redundant.

It provides input switching and a volume control, but as illustrated above, a passive pre amp (a ludicrous name for it) is effectively an empty box.

If you only have one source and it has an output level control (or maybe you use a DAC with multiple inputs) you can ditch the pre amp, save some money and remove one extra step in the signal path - which can only be a good thing.

The impedance comments above are a red herring, domestic audio equipment isn't impedance matched in the same way pro gear is. Domestic sources are low impedance, domestic sinks (not the kitchen variety) are high impedance. There is no impedance matching going on.

One fair comment is that the levels may be mismatched - a function of the lack of a decent standard for 'line level'. This can be overcome with attenuators, but this would be an argument for using a pre amp.
 

Gazzip

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Jan 15, 2011
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andyjm said:
These days, with source devices (streamers, DACs, CD players etc) all having line level outputs, a pre-amp is effectively redundant.

It provides input switching and a volume control, but as illustrated above, a passive pre amp (a ludicrous name for it) is effectively an empty box.

If you only have one source and it has an output level control (or maybe you use a DAC with multiple inputs) you can ditch the pre amp, save some money and remove one extra step in the signal path - which can only be a good thing.

The impedance comments above are a red herring, domestic audio equipment isn't impedance matched in the same way pro gear is. Domestic sources are low impedance, domestic sinks (not the kitchen variety) are high impedance. There is no impedance matching going on.

One fair comment is that the levels may be mismatched - a function of the lack of a decent standard for 'line level'. This can be overcome with attenuators, but this would be an argument for using a pre amp.
I have done a fair bit of listening to DACs with variable output stages. These are most notably the Chord DAVE, Esoteric D-07X and my current DAC the PS Audio Directstream. I really wanted to ditch the notion of a pre-amplifier for the logical reasoning as described by andyjm above, so was desperate for the direct approach to work. However in each case the removal of a dedicated linestage from the chain in favour of each of the aforementioned variable output DACs resulted in, to me at least, a very flat and lifeless sound. Subsequently (and it was after the event) I discovered that there are many others out there who feel the same way as I did about this.

It could be that I just don't like a HiFi sound in its purest, most direct form. I suspect this to be true for many reasons, not least that I am a BIG fan of valves over SS in the linestage. However my point here is that I simply did not like the sound that my DACs were producing in direct mode. It may very well have been uncoloured and lacking distortion, but it didn't sound right to me. So please don't discount a preamp just because it adds something to the sound produced and cannot therefore be defined as "hi-fi". That something added might just be the sound you are craving...
 

insider9

Well-known member
Sep 20, 2016
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Thanks for all above replies!

It's clear I've underestimated the role of a preamp. Even in an integrated like mine where in a way of a preamp you only get volume and input selector it's clear from your replies that it significantly impacts on sound.
 

Benedict_Arnold

New member
Jan 16, 2013
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First of all, there is a standard output voltage range for line level (RCA) outputs (taken from Wikipedia):
Line levels and their approximate nominal voltage levelsUseNominal levelNominal level, VRMSPeak amplitude, VPKPeak-to-peak amplitude, VPPProfessional audio+4 dBu1.2281.7363.472Consumer audio−10 dBV0.3160.4470.894
This is an alternating quasi-current, by the way. I say quasi, because it's more about a voltage signal than the transfer of energy. Typical modern audio equipment has an impedance at the low end of the 100 to 600 ohm range, so using the O-lvel V=IR gives you a current of between 0.017 (high) and 0.003 amps.

This from wiki:

As cables between line output and line input are generally extremely short compared to the audio signal wavelength in the cable, transmission line effects can be disregarded and impedance matching need not be used. Instead, line level circuits use the impedance bridging principle, in which a low impedance output drives a high impedance input. A typical line out connection has an output impedance from 100 to 600 Ω, with lower values being more common in newer equipment. Line inputs present a much higher impedance, typically 10 kΩ or more.

​So if you take 1.736 volts peak and divide it by 10,000 ohms you get a current of 0.17 milliamps, or in highly technical terms the cube root of eff-all.

As for the function of a pre-amp these days, yes, providing you're not using a turntable, you really don't need one except as a volume knob and input selector. That's really why a lot of DACs (Chord DaVE, Cyrus DAC-XP, and others) now integrate the volume knob and selector switches with the DAC (not the other way around as certain manufacturers might lead you to believe).

As for the influence on sound rather than volume, one would argue that the ideal pre-amp, indeed the power amp as well, should have zero effect on the sound. However, we humans all tend to like different sorts of sound. Some prefer the "warm sound" of valve amps, whilst others prefer the detailed or "bright" sound of transistors, and that's where the choice of pre-amp, matching your pre-amp, power amp, sources and speakers all comes into play.
 

MajorFubar

New member
Mar 3, 2010
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NSA_watch_my_toilet said:
In my hifi gear collection, I have a reknowned passive hifi preamp of rotel.



... it makes not a lot of sound by himself. So does different preamps. But, as an other member said, even if a majority of preamps are completely transparent and just amplify an incoming basic volume, some could bring colours.

After that, you have, now, CD players and DAC that can be directly connected to power amplifiers. This is possible. I don't know what is required to doing this, but it's possible.
I remember that. Rotel RHC-10. King's ransom for nothing more than a couple of source selectors and a volume-pot linked via an empty PCB to a row of RCA sockets. Basically the exact same thing Maplins would have sold for about £20, albeit that the Rotel is in a prettier box. Then you wonder why people like me are cynical about so called hi-end HiFi.
 

mond

New member
Jan 11, 2011
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You may find that adding an analogue preamp instead of using a built in digital volume control (which I think is what is on the WXC50) will give you a more preferable sound, this was certainly the case with me on my own system. I say preferable rather than better as it may be a matter of taste, but I certainly found adding a simple remote control volume control (preamp) between my digital source and my power amp made the sound much smoother and less harsh, and I wouldn't go back to using the streamer directly connected to the power amp. On the Linn forum opinions are split with some preferring the direct sound which may have slightly more information but is not so easy on the ears.

A good preamp can make the sound of your system more enjoyable so I would recommend trying the various options open to you first if you can to see which you prefer...
 
Feb 18, 2015
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Apparently..Naim and it's dedicated following swear that the choice of the pre amp section of it's vast array of amplifiers is of more importance to the sq than that of the power amp section within it's two box solutions.
 

insider9

Well-known member
Sep 20, 2016
740
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On one hand I'm glad I asked, on the other not so. This thread is going to cost me dearly as I can see my next amp upgrade as pre+power combo *YES*
 
Feb 18, 2015
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You should turn to the dark side and embrace the sound of naim.lol.

Seriously though.....naim are the masters of the pre/power approach to amplification...I'm not saying that they are the best sounding thing ever..and you either love them or hate them,but if you value musicality above analysis then you should take a look.Also they have a vast array of products and are probably at the forefront of the streaming technology side of the business,take into account upgradability,product support,build quality and this fantastic British company is probably second to none....and now I'm going to be slated by the naim haters.lol.but I am from the north side of the border and should probably have allegiance to that other company who used to make turntables .but alas I don't believe in company allegiance.... just good solid craftsmanship.......funnily enough I've not had a opportunity to listen to the linn products.
 

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