2. amps-preamps
  3. 181941-2029

Impedance and Sensitivity

Hi All,

I have made a move from inefficient speakers and large amps with high current supply to smaller amps and more efficient speakers. Think like 300 to 500 WPC at 8 ohms changing to 25 or 50 WPC at 8 ohms and speaker efficiency increasing to 98 or 100 Dbl from 87 Dbl.

I have always kept an eye on the output impedance of the preamp compared to the input impedance of the amp. I understood that if the input impedance of the amp was not at least 10X of the output impedance of the preamp, I could experience a negative impact on the bass response of my system.

As I try different preamps and amps with more efficient speakers, I have run into a new problem. This problem is that the gain of one of my preamps is 26dbl and, pairing it with a tube amp with an input sensitivity of 0.5 volts, results in not being able to adjust the preamp volume control so that my system plays more quietly. I run out of clicks for it to play more quietly.

I realize that either a preamp or a amp change can fix this. Not sure if in line attenuators is an answer as I suspect it adds a distortion or tonal coloration.

In the meantime...does this "gain" imbalance impact sound quality or is it just a loudness problem?

Thanks for listening,

Dsper

 

 

 

 

dsper
ditusa's avatar
ditusa
1,743 posts
 

@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

gryphongryph
352 posts
 

Mike recommended me the mid mono’s for my pre amp.

dsper OP
658 posts
 

@ditusa 

I get the horn monos with an all horn speaker.

I just worry that the amps would not drive the Forte's well given their 12 inch woofer and 15 inch passive radiator...

Will have to give Quicksilver a call.

 

ditusa's avatar
ditusa
1,743 posts
 

@dsper Wrote:

I get the horn monos with an all horn speaker.

My speakers are hybrid with two 15'' woofers and a horn, system 4435. See below:

Will have to give Quicksilver a call.

I agree with calling Quicksilver and asking for their advice.

Mike

https://www.lansingheritage.org/html/jbl/specs/pro-speakers/1984-4430-35.htm

 

dsper OP
658 posts
 

@ditusa 

Thanks, I have a lot to learn yet!

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