Herman, well put. I think another factor that hasn't been mentioned is the that highly efficient speakers could play an important role in getting sufficient gain from a system where a passive preamp is used.
Who is using passive preamps and why?
Seldom has there been any discussions on passive preamps in the forums and although my experience with them has been limited I have found them so far to be very enjoyable and refreshingly different. They seem to fall into their own category, somewhere between solid state and tube. Finding a preamp that is satisfing has been difficult. Some active solid state preamps can be very good but they seem to inject grain to some degree in the upper registers and some tube preamps are not too far behind. So far I think they should at least be matched up with an amp that has sufficient gain which is often overlooked. Which passives are you using and with what amp? Why do you like them?
- ...
- 173 posts total
I completely agree that some components demand that you use an active preamp and such systems are capable of superb performance, but I think perhaps you missed my main point. The main point of my post was that it is not the passive volume control causing the problem some experience, it is trying to use it with the wrong components. Let me try again. ALL systems consists of some source of an electrical signal, usually a DAC chip or a phono cartridge these days, followed by a series of active devices that eventually amplify the voltage to a level sufficient to drive the speaker. At some point in this chain of amplifiers you must include a passive volume control. To keep it simple let's concentrate on a system that only plays CDs. The most common way to do this in a high end system is to have some amplification inside the source which amplifies the DAC chip output up to around 2V. That feeds an active preamp which may or may not amplify the voltage but contains at least a passive volume control and a buffer. That is followed by an amp that further amplifies the voltage and can supply enough current to drive the speaker. There is nothing magical about putting the volume control where it is. It could be in the CD player, it could be at the input to the amp, or if the output of the CD player is robust enough and the amp input is benign enough so the buffer isn't needed it could be put in a separate box between the CD player and the amp which we call a passive. My point is if you blame wimpy sound on a passive it means you don't understand what I stated above. How about this? I don't have a preamp of any kind. I'm using Pure Vinyl software which controls the volume in the digital domain using 64 bit math. I modified the source so the DAC chips are connected directly to the input triode tubes of my amp through a 1:1 transformer followed by 2 more triodes. In case you are interested they also just release a version called Pure Music which doesn't include the vinyl functions. Check it out http://www.channld.com/pure-music1.html . |
03-16-10: Phd TVAD, you have the ultimate preamp! The VRE-1 is very spendy but beautiful and one day I will own one even if I have to wait. Phd if you would like a preamp that is as Mr. McCormack puts it right up there with the best might I suggest you try the McCormack TLC-1 with the Ultra upgrades from SMc. I had this upgrade done on my TLC-1 Deluxe and the difference was night and day. With the stock TLC lack of dynamics was not a concern (as far as going from quite to load passages), I had that in spades with the pair of DNA-1 mono-blocks, what did concern me was the lack of drive in the base region, it seemed like the slam was lacking when compared to the active output of my Micro Line Drive with Gold upgrades. At one point I had considered getting an ALD-1 for a comparison to see which I would prefer. The TLC Ultra completely eliminated any of these concerns. I guess this could be accounted for by the fact that to use the step attenuator that Steve builds, he has to convert the passive output to a buffered output. I had tried both the passive and buffered on the stock TLC and it wasnt quite the same. The TLC Ultra is leagues ahead of the stock TLC, so much so that you start to question what else in your system could be hindering the sound. Anyway just a suggestion and food for thought if your interested. |
Ig316b, I would agree with you about the TLC-1. I borrowed a CJ PF1 solid state preamp to see if this active preamp would actually sound better than the TLC-1. I gave it 24 hours of continous operation. It was a bit more dynamic but the TLC-1 sounded far better in the midrange/vocals but with a smoother (grain free) top end, also transparency was far better. Now this is the stock TLC-1, I can only imagine how good the TLC-1 would sound with the ultra upgrades. You already know that I like the McCormack products and still own one his amps as well. |
- 173 posts total