2. amps-preamps
  3. 1042062775

preamp vs. no-preamp

Hi guys, I would like to know your opinions regarding the classic question (which also has been posted many times in this forum, I know, I know) whether or not a preamp is needed for a good (= musical sound). You see, if you can delete the preamp and connect the DAC into the poweramp, you can save lots of money, sometimes up to $ 15,000 for a Conrad-Johnson ART (this is off course an extreme example). The money you have spent on the preamp can be used for buying a better source or amplifier (mono's?). So theoretically if you don't have a preamplifier you can improve the sound reproduction by: deleting redundant audio circuitry and interconnect cables, upgrading the quality of you source, poweramplifier or speakers.
My personal experience is that without a preamplifier the sound is becoming thin and uninvolving, but I know there are audiophiles who don't have a preamp in their audio system.
dazzdax
sean
6,231 posts
 
Passive's are not "preamps". A "passive" is simply a "line level attenuator" that may also function as a "line level switchbox" if it has multiple inputs. While one could argue that it is a technically a "pre-amplifier" because it is before the amplifier, the name "preamplifier" came about as there was a need for amplification prior ( or "pre" ) the final gain stages of a high level amplifier. As such, a "preamp" was "amping the signal prior to the main amp".

Let's get the terminology right, stick to it and use it accordingly. Either that, or you'll all be forced to write a 5000 word essay on the subject. Preamp's have a gain stage : ) Sean
>

PS... Don't get me started about buffered units. All hell would break loose then : )
gboren
143 posts
 
If a preamp actually amplifies, where on the volume control is zero gain? That would have to be about 5 oclock on the dial, which we never use. So why would we want to amplify a signal just to attenuate it?

I understand that a preamp doesn't actually amplify, rather it optimizes impedences to optimize power transfer. Of course, whether one can hear the difference continues to be the subject of debate (in my mind as well).
twl
3,251 posts
 
Remember that all passives are not alike. There are resistive and transformer based passives. There are significant differences in the impedance matching characteristics. The transformer based passives may not exhibit any of the problematic qualities that many of you have experienced in your resistive passives. They should not be "lumped together" because they are very different.
marakanetz's avatar
marakanetz
5,473 posts
 
Gboren the gain is the constant value on the most of the preamps. There are preamps with variable gain. Turning volume up or down you still working with already amplified signal.
Changing the volume by changing the amp's gain is not efficient and will not sound right.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Come on Sean, jeesh, I'm sorry. That's what people were calling them in the very early 90's. Technically, you are correct. However, I will not be submitting a 5000 word essay.

........passive preamp.. whoops I said it again...hehe...buffered unit.....couldn't resist it.

Regards,
John
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