Active or passive preamp

For what it's worth, I ran a Sonic Euphoria passive line stage for years with an Aragon 3002 amp, and never had a problem with an impedence issue, always had as much volume as needed with that combination. I don't recall the input impedence on the Aragon, but the combination worked very well for me.

Regards,
Dan

I have used an Aragon 8008bb amp with an EVS attenuator which is fixed resistor. Im not going to sell either piece as that Aragon sounded better then my Levinson and the EVS has a transparency none of my 12ax7 or 6sn7 pre amps could match. But; and a big but; together they were meh. Always moving the sub crossing frequency and dealing with room bass nodes. After discovering impediance matching I bought a Bent silver tvc and found bliss. Two months later I gave up on the low sensitivity rig and now its speaker to set amp impediances Im dealing with.

S&B removed their website that showed this.

For a while the URL I bookmarked still displayed that page even though S&B removed it from view on the public site. However, now the URL is dead too. That was a very informative chart. Don't know why S&B felt the need to remove that page.

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.

Hey,

The Z-out is a function of three things. Source impedance driving the inductive volume control, step down ratio and DCR of the coils.

In the case of an autoformer with a 50 ohm DCR the Zout is as follows. (numbers quickly read of a log graph so are approximate)

1K @ 0dB
505 @ -3dB
252 @ -6dB
76 @ -12dB
22 @ -18dB
8.2 @ -24dB
2.8 @ -30dB
1.5 @ -36dB
.58 @ -42dB

The input impedance at low frequencies is the parallel combo of the primary inductance and the reflected load. and in the case of the autoformer above it will be down 0.1dB @ 11hz

dave