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View Full Version : Does an amp need a preamp?



dude
2006-09-21, 17:53
I've only owned recievers my whole life and want to replace my current one. I will only be running my squeezebox into it. If I buy a basic 2 channel stereo amp do I need a preamp (and then obviously I may as well buy an integrated amp)? Thank you.

pfarrell
2006-09-21, 18:18
dude wrote:
> I've only owned recievers my whole life and want to replace my current
> one. I will only be running my squeezebox into it. If I buy a basic 2
> channel stereo amp do I need a preamp (and then obviously I may as well
> buy an integrated amp)? Thank you.

Need? It depends.
A preamp technically is not needed. This has come up lots of times on
this forum.

But, you need to match gains. The SqueezeBox (and Transporter) can put
out signals that are very loud, and could harm your speakers and
hearing. So for safety, you should match the levels without relying on
the SqueezeBox's volume control. This is why folks recommend external
attenuators. With them, you can set your system so that with the
SqueezeBox volume is WFO (wide open) it is just louder than you ever
want to listen to music.

(Which assumes that your amp has the power to go that loud without
clipping, as clipping will really destroy a speaker fast, seconds or less).



--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

ezkcdude
2006-09-21, 18:19
I've only owned recievers my whole life and want to replace my current one. I will only be running my squeezebox into it. If I buy a basic 2 channel stereo amp do I need a preamp (and then obviously I may as well buy an integrated amp)? Thank you.

Not necessarily. What you want to do is test your amp, by running RCA's from the Squeezey directly into the amp. Make sure before you attempt this, that you turn the volume ALL THE WAY DOWN. Once you have it connected, start turning the volume up. If you get to full volume, and it is still not loud enough for you, then you need a preamp. This will give you the additional gain. On the other hand, if it is way too loud at a very low level, then you may want to think about getting some passive attenuators.

joncourage
2006-09-22, 09:17
There have been some threads elsewhere indicating that a pre-amp does something that enhances the sound quality - all the usual, soundstage, etc etc.

I don't recall seeing the science behind this conclusion, just that experiments on the part of the posters of this opinion have resulted in this.

Some further research may turn up the above-referenced posts.

If anyone knows why this may be true, it might be interesting to understand better, or maybe it's "just one of those things".

I too basically have no need for a pre-amp for the same reason (SB is my only source for 2-channel), and I think I've asked the same question before. Sure would be nice to invest the $ into better amplification rather than an unneeded pre-amp, as long as the gain/attenuation issues are heeded.

highdudgeon
2006-09-22, 09:33
Jon,

If anything, one more component and one more set of cables in the signal path will degrade your output. At the very best -- very best -- the preamp and cables will be perfectly transparent. In other words, they will have no effect at all.

Of course, this is not always the case. Many components are designed, by accident, purpose, or by default, with frequency bumps or the like. A tube preamp will inevitably sound different from a solid state preamp. It will not be as transparent or accurate (don't take my word for it. Call McIntosh Labs and ask to speak with Chuck Hinton, their technical rep. They sell equally excellent and very expensive solid state and tubed gear; he will tell you in an instant that there are subtle differences, but that, ultimately, on the bench, the solid state gear is more accurate.) and it might be euphonic. This is not necessarily a bad thing, either -- depends on your taste. Cables, too, can have subtle frequency shifts and people will argue for days, with terminology akin to the world of wine tasting, as to which is better (oddly, without taking measurements).

Preamps were definitely necessary when components put out much lower signals. Today, most components have line level output, and that means you can run them straight to the amp...provided they have built-in attenuation (some CD players, like the Audio Aero, which I have owned, do just that).

Anything else is, I'm sorry to say, hype.

This is one reason why the Transporter is a such a cool device. You can set the internal analog attention and, in one box, it becomes transport, DAC, and line stage.



There have been some threads elsewhere indicating that a pre-amp does something that enhances the sound quality - all the usual, soundstage, etc etc.

I don't recall seeing the science behind this conclusion, just that experiments on the part of the posters of this opinion have resulted in this.

Some further research may turn up the above-referenced posts.

If anyone knows why this may be true, it might be interesting to understand better, or maybe it's "just one of those things".

I too basically have no need for a pre-amp for the same reason (SB is my only source for 2-channel), and I think I've asked the same question before. Sure would be nice to invest the $ into better amplification rather than an unneeded pre-amp, as long as the gain/attenuation issues are heeded.

pfarrell
2006-09-25, 12:32
There have been some threads elsewhere indicating that a pre-amp does something that enhances the sound quality - all the usual, soundstage, etc etc.


I can't see how adding signal processing improves a signal. But some folks like to use tube pre-amps as tone controls. They can add a 'tube warmth' which is usually just rolling off the top and bottom of the spectrum.

And of course, tubes can add some nice intermodulation distortion. Which is why I play my Gibson ES355 thru a tube Fender amp.

badbob
2006-09-25, 12:46
I personally wouldn't use a SB straight into a poweramp, just in case of power on/power off thumps, or if the volume dial is reset to 100% or someone messed around with it. Depends also how the pre-amp is controlled in the SB, it could be better to use line out to a good quality pre-amp and control the volume on the pre-amp and not the SB.

highdudgeon
2006-09-25, 13:00
I agree -- it is taking a risk. At the moment, I'm running it through a DAC with a volume control.


I personally wouldn't use a SB straight into a poweramp, just in case of power on/power off thumps, or if the volume dial is reset to 100% or someone messed around with it. Depends also how the pre-amp is controlled in the SB, it could be better to use line out to a good quality pre-amp and control the volume on the pre-amp and not the SB.

richidoo
2006-09-26, 16:41
Receiver is a good way to go for convenience, price, features and in some cases, believe it or not, sound quality. One of the best sounding receivers in the world is the Arcam AVR-300 ($2000)and new AVR-350 ($2500). The 300 has been out for a while, can be had used for lot less. They have real power supplies and great high end design engineering. Every review and forum comment I have ever read ranked them very high in audio quality,even in direct comparison to high end seperates. The internal DACs, preamp components, and power devices are all excellent high end parts. It is worth a listen before you plunge into the insane world $eperate$. I am trying to decide to go seperate or go back to receiver. After having a nice integrated tube preamp and finding the limits of its performance I am learning that the music itself is so much more important to me, rather spend money on music than audio gear.