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 2 responses by ngjockey

ngjockey
1,042 posts
 
For the record, TVC's have an output impedance below 100 ohms for all but the highest 2 or 3 steps. In fact, the first half is usually under 1 ohm. S&B removed their website that showed this.
ngjockey
1,042 posts
 
Haven't seen any other published spec's.

As I remember, Zout was something like:

1400 ohm @ 0 dB
140 @ -3
14 @ -6
1.4 @ -9
and so on, down the 24 steps, except the steps weren't exactly linear (logarithmic) and they never rated for the option of gain. Seen worse numbers from tube line stages but that's more of the exception than the rule.

I'm feeding less than 10Kohm (parallel active high pass/low pass) but since my volume setting never gets above two-thirds (CDP starts to skip with bass notes), impedance and roll-off is not an isssue.

Zin was the opposite and 2 Mohm (JFet territory) at 0 dB sounds familiar. Forget the minimum but that's hardly an issue against the Fletcher-Munson curve. However, capacitance of associated equipment and cables becomes an issue, which, for us laymen, is the least understood part.
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