Why do you use a passive preamp over an active one in your system?

Shadowfax said:
I usually run in Normal Gain, but find when I play it at the same volume in the BP Mode, I can still have a conversation in the room because the slam in missing. So again I assume that is what is meant by "lacking dynamics"?

So how does my VAC differ from one or the other, if there is a simple explanation?
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No, the lacking dynamics with a passive pre are due to impedance mismatch and the robustness of the source output stage.

With VAC in Buffered Passive mode, since it works at unity gain (0dB gain), you get to hear more of the sound character of your CD player output stage. When you select the Normal or High gain, the VAC pre enhances dinamically the sound signature of the Rotel player with its own gain stage signature. But there are sources with output stages that do not need this enhancement from a preamp.

A buffer assures there won't be an impedance mismatch, but will not enhance the sound produced by the source. If the sound lacks dynamics in Buffered Passive mode, it means the source lacks dynamics.
 
Joe

I have not had any issue with the Wyred and either a TT/phono pre or any DAC I have tried with it. If the DAC has XLR outputs the same rules apply as with the Lumin.
 
I know, it must be a great piece. Thanks!

Jack said:
Joe

I have not had any issue with the Wyred and either a TT/phono pre or any DAC I have tried with it. If the DAC has XLR outputs the same rules apply as with the Lumin.
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I also have had no issues with the STP-SE. I use XLR from the DAC and RCA from the Marantz spinner... both work great and are very dynamic.
 
Anatta said:
the VAC pre enhances dinamically the sound signature of the Rotel player with its own gain stage signature. But there are sources with output stages that do not need this enhancement from a preamp.
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Of the posts made by people who heard both active and passive across different forums, my impression is that a significant proportion of them preferred active, e.g.
http://www.audioshark.org/showthread.php?t=9753&p=167944&viewfull=1#post167944

While a number of those cases could have been caused by passive preamp configuration issues like impedance mismatch or source/cable problem(s), I speculate that the majority of people simply prefer the enhancements made by an active preamp - especially a tube preamp - instead of a unity gain preamp that may possibly sound closer to the actual recording in theory.

In the audiophile world, more accurate audio reproduction may not necessarily be felt as the more "musical" or "emotionally engaging" playback. I once did an A/B comparison between the 300B SET tube amp I've been using and the class-D amplifier my company makes, and the result...
 
Great thread Joe.

Last year I had tried a Tortuga LDR with a DSPeaker 2.0 as the dac (as well as room correction) and a ss amp with a gain of 34db. I can't remember if I was using the output of 7v with single ended or 14v with balanced on the DSPeaker but it seemed to be too much either way as it didn't sound as good as the Rogue Perseus I had at the time. The DSPeaker also has a low output impedance of 10 ohms from what I read and maybe it just wasnt a good match. I tried all the input impedances of the Tortuga but could never get a sound that I thought was better than the tubed preamp.

Fast forward to now I have a Lampi L4 dac with 2.5v output and 600 ohms of output impedance going into the Hattor passive going into the Nord amps that have 26db gain and I'm getting fabulous results. I don't know if its the constant input impedance of the Hattor that Arek Kallas has implemented or if I just have a good match between all the components but the Hattor is providing a window into the music that I'm not getting with my current tubed preamp (not the Rogue). The detail and level of realism is uncanny.
 
Thanks Tom, I've always been curious and in my limited experience have preferred a preamp to no preamp and an active one as opposed to passive but am willing to try again assuming conditions are right.
 
OMG, limited experience, really Joe :D.... I dare say you have tried more equipment than any of us :)....
 
I have not. Mainly because I am worried that a glitch or something may end up giving me full volume and I'll have no way to control it other than to pull a power cord. With a preamp, at least I have some control in between.

the professor said:
Joe

Have you tried going from your Lumin straight into the Ayre amp?
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joeinid said:
I have not. Mainly because I am worried that a glitch or something may end up giving me full volume and I'll have no way to control it other than to pull a power cord. With a preamp, at least I have some control in between.
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In case some day you want to try it, enable Volume Control and disable Digital Audio Output in Lumin app. Turn down the volume and verify it before you attempt a direct connection. You'll then be using the 32-bit digital volume in the ESS9018 chips in the Lumin S1:
http://www.esstech.com/files/3014/4095/4308/digital-vs-analog-volume-control.pdf

Note: The high 2Mohm input impedance of MX-R Twenty, or the 1Mohm input impedance of M400, are ideally suited for direct-to-amp experiments (not recommendations) whereas Pass .5 series with low 20kohm input impedance is less suitable.
 
Ive used the Lumin straight into amps before and it was pretty dang good. If I only used the lumin as a source id be very tempted to sell the preamp.

Worth a try. I do believe the Lumin is extremely stable.
 
Joe,

I use the Nord Class D power amp and have got the Khozmo preamp in the system and it works really well. I am looking to get the Hattor as that has XLR outputs. For me the passive attenuators give a very natural, relaxed and 3D type of sound. TVCs and active preamps tend to give you a more upfront sound with tight driving bass. The actives do not have the same amount of detail as resistor passives, unless very good. I find the resistor passives easier to listen to for a longer time. A lot of active preamps are very upfront and in a few cases a bit wearing and overly impressive. IMHO they give you a real taste of the high end without the super price tag which can only be a good thing.
 
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