2. amps-preamps
  3. 1325552222

Active or passive preamp

Hey guys,

I need some advise as to whether I should go active or passive on a preamp. Although I have several digital sources, I'm running all of them through an Emotiva XDA-1. It's nominal voltage output is 1v with a max of 7v. Its output impedance is 1K ohms.

My amp is an Aragon 2004, with an input sensitivity of 150mv for 1 watt. Its input impedance is 22K ohms.

Although I've been doing as much reading up as I can, I'm still not sure that these components will be a good match with a passive preamp.

What do you guys think?

Thanks.
tonyangel

Showing 3 responses by brownsfan

brownsfan
1,508 posts
 
Ngjockey,
Thanks so much for that information! I have looked high and low for output impedance on TVC's to no avail. All I ever got was a nonspecific "lower than resistor based designs." Is that true for all TVC's, or only the S&B's?
brownsfan
1,508 posts
 
I don't think I would run a passive into an amp with an input impedance of 22K ohms. I love passives, especially TVC's, but I think that is pushing it.
brownsfan
1,508 posts
 
Yes, an amp with a higher input impedance would be preferable. There is a rule of thumb that the input impedance of a component should be at least 10 x the output impedance of its upstream component. I'm about 38 years removed from my last physics class, so I defer to someone else to provide you with the math. Failure to observe the 10 x rule can result in attenuation of the signal at frequency extremes.
Since I like to use passives, I tend to stick with amps that have ~ 50-100 K ohms where impedance mismatch is not an issue. Then the only consideration is making sure you have sufficient gain.
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