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Active pre-amp versus passive attenuator?

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ralflar

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The new Channel Islands Audio passive attenuator PLC-1 is now shipping. I am tempted to upgrade from my VPC-2 because of the added convenience of remote volume control and the need of extra line inputs. One day even the HT passthru feature might come in handy.

The PLC-1 costs $900. For about twice that much, very decent active pre-amps can be had. So:

What would be the benefits, especially regarding sound quality, of a solid state active pre-amp under $2000 over a passive line stage?

(Here I should say that I am not interested in tubes or hybrids, and that my line output levels are more than high enough to drive a passive stage.)
 

risabet

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Is there some reason tubes and hybrids are off limits? My knowledge of passives is not vast but I think you need to make sure that the output impedance of the passive is 1/10 or less than the input impedance of the amp you'll be feeding, though if they're from the same company that shouldn't (hopefully) be an issue. The same should hold for the output impedance of the sources compared to the input impedance of the passive.
 

ralflar

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Yes there is. I do not want a tubed system, at least not yet. I started to write up why. That took me way off topic, so I scratched it. Sorry, let's leave it at that, for now, and for another thread.

Good point about input/output impedance matching. While this is no problem within the CIAudio family, it might be when using gear from different manufacturers. Long interconnects between the passive attenuator and amp might be another. My connections would be under 2 meters, so I should be fine in this respect, too.

Considering my preference for solid state, and ignoring the price differential, why would I choose an active pre-amp over a passive, or a passive over an active? I am very interested in your observations and opinions.
 

risabet

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Fair enough on the tube issue:). As I stated originally, I am no expert with passives, but with all the passives I've heard IMS their is a trade off between transparency, which passives have in spades, and life and dynamics, which all the passives I've heard lack in spades. Keep in mind that I haven't heard any of the TVC passives.

For my money and sonic preferences I need an active unit to give me the dynamics and life I like. Notice that my current system is all tubes. This should give you some idea that I like a more rounded sound than I got from previous SS systems. That is not to say euphonic, but I do like the warmth that tubes add. At the moment, I would definitely own an active unit for the reasons above.
 

ralflar

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Interesting. I don't really grok "transparency" but think I understand "life and dynamics". The funny thing is, life and dynamics are two of the aspects I like so much in the VPC-2/D-200 combo! Then again, I am fairly new to this. I won't mind it at all if I can find something even better - preferably a lot better. :)

My dealer will probably let me bring in the VPC-2/D-200 combo to compare it with <expensive pre-amp>/D-200 and <expensive pre-amp>/<expensive amp> combos. You convinced my that I should try this. Thanks.
 

amey01

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Anecdotially, I've never been impressed with the sound of passive preamps - especially the bass, it never seems as controlled or defined. I think systems (read: sources) can benefit from a bit of impedance matching that a powered preamp provides.
 

ralflar

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Replacing my receiver's pre-amp outs with the VPC-2 improved every aspect of the music reproduction, including cleanliness, depth, speed, and thightness of the bass. The difference was not subtle, it was remarkable. I find it hard to imagine how a pre-amp could improve upon the bass any further. Now you guys make me really curious. Even better things coming my way? Well! Tomorrow I am going to the shop to pick up my Arcam DV137 replacement player. (Hopefully this one will work.) I think I'll use the occasion to see which pre-amps they have available for audition this weekend...
 
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