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Dave Cook Dave Cook is offline
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Default Active vs. passive pre-amp

Out of curiosity, I hooked up my DAC directly to my amp just to hear
what it would sound like without going through my preamp. The DAC is
fed by a Squeezebox Touch, so I can use it's digital volume control
for attenuation. I was rather shocked how much more vibrant and
involving the sound was. It does make me wonder what the benefit of
all that electronics in a pre-amp really is. So I'd like to try
going passive with something like a stepped attenuator.

Is there anything I should know about the downside of going passive?
It does sound like there might by some loss of bass, though I'd like
to narrow this down with whatever measurements I can do with my
voltmeter and SPL meter.

My typical "serious" listening level is about -20dB (relative to unity
gain). A low level recording might require the volume to be raised to
-15dB or so. So I don't think I'll have any problems with having
enough gain.

Equipment, all connected with XLR cables, is as follows:

DAC: Cambridge Audio Azur 840C. Output impedance: 50 Ohm. This
seems to have a pretty beefy power supply for a CDP/DAC.

Pre-amp: BAT 3iX, Output impedance: 1000 Ohm

I also have BAT's VK-42SE solid state amp on loan, but it still seems
too smooth and laid back for my speakers, which are already laid back.

Amp: BAT VK-250
150W @ 8 Ohm
Input impedance: 100K Ohm. Should be any easy load?
Gain: 26 dB

Speakers: Vandersteen Quatros, not very efficient but an easy load for
the amp.