2. amps-preamps
  3. 1404294640

Active vs Passive Pre amps

I know this is'nt a new subject, but I would appreciate your views folks. At the moment I am using a Passive Pre, equivelant to the Music First Audio baby reference, but built by an independent engineer. I use it into my ARC Reference 75 power amp, into Daedalas DA-RMa speakers. To be frank, I am very happy with it. The only drawback is the dual volume pots only have about 18 stops available, so you tend to go from too soft to too loud. When the dealer delivered the ARC power amp, he used it briefly with an ARC Ref 3 Pre and I preferred the passive, but it was a limited listen with a new, non run in Power amp.

The passive seemed more neutral and detailed, the ARC a little rich and lush. I know you are supposed to lose dynamics with a passive pre. The question I suppose, is whether it is worth trying to get hold of an ARC Ref 3 or maybe an LS 26/27 and comparing again? Do you think ARC power amps should sound better with an active ARC Pre, which are'nt cheap, even second hand? If I am going to stick with a passive pre, are there better options than the MFA baby reference?

Thanks
david12
brownsfan
1,508 posts
 
David, If you initially evaluated the Ref 3 and preferred your passive, I don't think that would be the correct move. As I read your post, the driver for you is better resolution in volume control, and perhaps better dynamics.

Usually, the stepped controls have finer resolution in the middle settings, with courser resolution at volume extremes. If the sensitivities and gains of your components allow you to stay in the 10:00 - 2:00 area on your volume controls, and you still don't have enough volume resolution, then you might want to narrow your search to infinitely variable potentiometer designs. As I am sure you are aware, there is a reason why so many good preamps used a stepped volume control rather than an infinitely variable potentiometer.

As a long time lover and advocate of passives, I can heartily recommend the Coincident Statement Line Stage as an active preamp that will satisfy your preference for neutral, detailed, and transparent presentation. It can be very sweet, but would never be described as lush, rich, etc. Israel Blume likes to say it sounds like nothing. It uses a stepped volume control, so you might want to shoot Israel an email to discuss your current equipment with respect to volume control resolution.
lak's avatar
Ag insider logo xs@2x
lak
4,537 posts
 
David,
I believe it's all a matter of personal tast. I agree with Brownsfan comments totally however for peace of mind you might want to once again demo a preamp in your home. I would think the dealer that you purchased the ARC Reference 75 power amp would be more then willing to bring out a preamp to demo or let you borrow one.
czarivey
5,697 posts
 
in reality it's very simple math instead of science:

passive volume control will vary resistance from valueA to valueZ where we can assume Z will be the the highest so to control the output voltage.

active volume control(active preamp) will have stable or fixed output impedance to supply variable input voltage to your amp.

by all possible and impossible means it means that supplied stable output impedance is preferable for best amplifier performance.

than you can do the rest of science to decide.
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