[laserboi]

Hey Everybody,

I recently had the fantastic opportunity to attend a McIntosh Labs training here in the Chicago-land area.  Let me first preface these next few paragraphs by explaining that I've been to quite a few vendor trainings as I work for a major Electronics Retailer.  I have never learned so much in a single training than I have at the McIntosh training so hats off to the fine folk over there.  During some explanations on basic sound/amp concepts a few questions were raised.

The difference between volts and current were explained as well as how the two combined to create "watts."  They also spent quite some time explaining their autoformers and how no matter what the impedance of your speaker you get the optimum performance.  Unfortunately my equipment and the majority of equipment out on the market does not use autoformers so i have a couple of questions regarding this specific topic.  From my understanding of what they were explaining, a speaker, which has a nominal impedance of 8ohms is designed for more voltage than current where as a speaker with 2ohms impedance needs more current than voltage.

1.  Is my very basic understanding of 8ohms vs 2ohms correct in that the higher the ohm the less current is needed and the more voltage is required or am I completely confused?

2.  If my understanding is correct then my speakers, Mirage M-3si's, which have a nominal impedance of 6 ohms and do not drop below 4ohms would not require an amp with gobs of current to operate optimally.  The amp that would be better for this speaker would be something that produces more volts than current in the watts equation.  Can it be said that I am correct with this line of thinking?

Now this is where I get REALLY confused.  My Mirage's are spec'd at 83db sensitivity at 2.83v, which sounds like a very inefficient design that would require a lot of power. 

3.What type of amp design would be optimal for my speakers?  The fact that they don't seem to need gobs of current would lead me to believe a tube amp would be great but then again their sensitivity keeps me thinking that a tube amp wouldn't have enough juice for these speakers.

Any help would be appreciated here folks and if I am completely off base please enlighten me as I love this hobby and need to learn as much as I can. 

Here is the review by Stereophile for my speakers, which also contains the specs towards the end.  http://www.stereophile.com/floorloudspeakers/1192mirage/index.html

Thanks in advance and by the way I normally would have posted this in audio central but alas it is gone.  Lonewolf if it needs to be moved please move it to the correct circle.

Regards,

Pete

[lonewolfny42]

Hello Pete...
Your post is fine.

Ah....the Mirage 3's...their nice speakers. Still have mine....I'd never sell them.

3.What type of amp design would be optimal for my speakers?  The fact that they don't seem to need gobs of current would lead me to believe a tube amp would be great but then again their sensitivity keeps me thinking that a tube amp wouldn't have enough juice for these speakers.

Well...yes and no.Since I've had the 3's for over 20 years...I have tried may amps with them. I prefer a "beefy" SS amp with these speakers....but a good higher power tube amp (100 watts+)...works good as well. But....to take advantage of all the Mirage speakers have to offer, a SS amp seems to sound better to my ears....much better lows (bass).
I see that your using Odyssey Stratos Extreme SE....it's a good match with the Mirage speakers. There is another Raver that runs his Mirage M-1's with Odyssey Mono's....a sweet system.

The difference between volts and current were explained as well as how the two combined to create "watts."  They also spent quite some time explaining their autoformers and how no matter what the impedance of your speaker you get the optimum performance.  Unfortunately my equipment and the majority of equipment out on the market does not use autoformers so i have a couple of questions regarding this specific topic.  From my understanding of what they were explaining, a speaker, which has a nominal impedance of 8ohms is designed for more voltage than current where as a speaker with 2ohms impedance needs more current than voltage.

I don't have any experience with autoformers....just what I have seen...Link....

1.  Is my very basic understanding of 8ohms vs 2ohms correct in that the higher the ohm the less current is needed and the more voltage is required or am I completely confused?

I believe your correct.

I recently had the fantastic opportunity to attend a McIntosh Labs training here in the Chicago-land area.....I have never learned so much in a single training than I have at the McIntosh training so hats off to the fine folk over there.

They run a fine tour....here's a video link.....

                    Chris

[laserboi]

Chris thanks for your excellent reply.  I appreciate you taking the time to answer my questions.  The fact that other people on this board have the same speakers as mine is also great to hear.  I hardly every hear about these speakers, which surprises me since they are so fantastic but I guess the fact that they are pretty old has something to do with that.     Thanks again.

[lonewolfny42]

Chris thanks for your excellent reply.  I appreciate you taking the time to answer my questions.  The fact that other people on this board have the same speakers as mine is also great to hear.  I hardly every hear about these speakers, which surprises me since they are so fantastic but I guess the fact that they are pretty old has something to do with that.     Thanks again.

Your welcome Pete...I just got on short time ago.

As for "old" speakers...most move to the "latest and greatest"....but there's still plenty of life in those "old" models. Vintage is not a "dirty" word.

[Mike19]

Hi Guys.

You both have a lot of knowledge on this subject. Very informative.

I am under the impression that, as a general rule, match a high sensitivity speaker (above 91 dB) with a low wattage Class A tube amp and a low sensitivity speaker (below 86 dB) with a high wattage Class A/B SS amp. I guess speakers with 87 dB to 91 dB could be used with a medium powered tube or SS; Class A, A/B or D.

Is this correct?

Mike

[lonewolfny42]

Hi Guys.

You both have a lot of knowledge on this subject. Very informative.

I am under the impression that, as a general rule, match a high sensitivity speaker (above 91 dB) with a low wattage Class A tube amp and a low sensitivity speaker (below 86 dB) with a high wattage Class A/B SS amp. I guess speakers with 87 dB to 91 dB could be used with a medium powered tube or SS; Class A, A/B or D.

Is this correct?

Mike

That's about right Mike...
A miss match with amps and speakers can give one a poor sounding system.
The "synergy" has to be "just right"....

[satfrat]

Hi Guys.

You both have a lot of knowledge on this subject. Very informative.

I am under the impression that, as a general rule, match a high sensitivity speaker (above 91 dB) with a low wattage Class A tube amp and a low sensitivity speaker (below 86 dB) with a high wattage Class A/B SS amp. I guess speakers with 87 dB to 91 dB could be used with a medium powered tube or SS; Class A, A/B or D.

Is this correct?

Mike

For an 87-89db loudspeaker I'd want around 150wpc @8 ohms myself,, which is what I have with my tube hybrid Butler Audio 3150.

Cheers,
Robin

[chosenhandle]

I own Paul Speltz's autoformers (linked above in the second post). They work as advertised and are fairly seamless in the systems I have put it into. Because I use OTL amps, I have to be very careful on speaker matching. The autoformers allow me to match almost any speaker to the amps.

In a perfect world, one wouldn't need the autoformers because you would match the amps and speakers to begin with, but I have changed my components over time and as a result have not had perfect combinations. Autoformers have solved that problem.

[zybar]

I own Paul Speltz's autoformers (linked above in the second post). They work as advertised and are fairly seamless in the systems I have put it into. Because I use OTL amps, I have to be very careful on speaker matching. The autoformers allow me to match almost any speaker to the amps.

In a perfect world, one wouldn't need the autoformers because you would match the amps and speakers to begin with, but I have changed my components over time and as a result have not had perfect combinations. Autoformers have solved that problem.

The Speltz Autoformers absolutely work as advertised and allow an OTL amp to mate with a much larger range of speakers.  However, I found that they imparted a slight haze over things and I could clearly hear when they were in or out of my system.

I tried them with Atma-Sphere M-60's and MA-1's.

George

[toobluvr]

...........

As for "old" speakers...most move to the "latest and greatest"....but there's still plenty of life in those "old" models. Vintage is not a "dirty" word.

"Latest and greatest" is the dirty word.....or phrase.

It turns you into a gear junkie that chases his tail in a search for "the ultimate".....which BTW, will never be achieved.....and makes you waste too much time, effort and $$!