Impedance and Sensitivity

I ran into this problem with my pre and power amp, my temporary solution has been in line attenuators 10db on my power amp input.

it works and I can not hear any degradation of sound quality, but I still don’t have a lot of volume adjustment before it gets too loud.

First my plan is to get a new dac as it also has a high output 4v.

Have my eye on a dac with a tube output at 1.5v which should maybe help my situation. Also have a dream power amp in future that has variable input gain but that is for when times get better economy wise.

@dsper You have put your finger on why lower powered amps also have less gain, since its an expectation they will be used with a more efficient loudspeaker.

A higher powered amp usually needs more gain since its more likely to be used with a low efficiency speaker. When you start mixing the two you run into problems like this.

What you might notice here is that the amps and speakers have differences in gain and sensitivity while the gain of the preamp can usually remain a constant, although in the last 25 years the gain of the preamp hasn't been as important. 26dB is a lot of gain in a preamp line stage these days.

@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.