Impedance and Sensitivity

@atmasphere 26dB is a lot of gain in a preamp line stage these days.

My CJ 17LS2 is probably twenty years old and has 26 dB gain with no switching to a lower gain. 

My CJ LP66S tube amp (50wpc) is also about twenty years old with 0.5 V input sensitivity. Interestingly, my newer First Watt F7 is 0.53 V input sensitivity and 25 wpc.

I was thinking that, for example, a pair of Quicksilver mid monos at 1.5 V input sensitivity might do the trick.

My problem is that I do not know how to relate amp input sensitivity to preamp gain. One Volt less of amp input sensitivity equals how many preamp dB?

Whoopee, this is fun!

Thanks for listening. 

@dsper Wrote:

I was thinking that, for example, a pair of Quicksilver mid monos at 1.5 V input sensitivity might do the trick.

I would go with Quicksilver Horn Mono's

Mike

My problem is that I do not know how to relate amp input sensitivity to preamp gain. One Volt less of amp input sensitivity equals how many preamp dB?

In preamps, 6dB one way or another is a doubling or halving of the voltage. From 1 to 2 volts is a 6dB increase and so on.

You have so much gain (especially with speakers like that) that you might consider a passive volume control. I'm not a big fan of them; an attenuator would work but means that you would be amplifying and then knocking the signal back down. If you keep the passive volume control as close to the amp as possible that seems to work better.

@atmasphere ...you might consider a passive volume control...

Benjamin at Mojo Audio, who made my DAC (1.5 V), also suggested that a passive might be the way to go. I do have a Luminous Axiom passive that I can try.

@ditusa I would go with Quicksilver Horn Mono's

Can you share your thoughts on why the horn mono's would be a better choice than the mid monos?

Everyone, I appreciate the feedback. Thank you!

@dsper Wrote:

Can you share your thoughts on why the horn mono’s would be a better choice than the mid monos?

The horn mono’s have lower gain I find work better with high efficient speakers. i.e. lower noise. My speakers have an efficiency >2.6% and a sensitivity of 96 dB SPL @ 1 watt 2 meters @ 8Ohm. For my system controlling gain is important for good sound quality.

From Quicksilvers site:

The Horn Mono Amplifier is designed specifically for use with very efficient loudspeakers. It has extremely low noise and distortion as well as having 18db less gain than Quicksilver’s standard amplifiers. This avoids the noise and gain problems that normally appear when using horn speakers. The amplifier is designed to sound good at the extremely low levels (milliwatts) that horn loudspeakers require. Many amplifiers actually have higher distortions at these low levels.

Mike