• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Opinions on Infinity QLS speakers anyone?

Bucky Badger

Bucky Badger

AK Subscriber
Subscriber
Hey guys and gals. I have the opportunity to pick up a pair of Infinity Quantum Line Source Speakers for a REALLY good price and before I jump off the deep end I was hoping to get some of your opinions. I know that they require a lot of clean power and have read what I can find on the net but wanted your opinions on how they sound and any other info you might have. I would be buying these from the original owner and he told me they are in 9.8/10 cosmetic condition as well as all the drivers are working without any trouble.
Anyway, thanks for your time and I wish you happy music.

Bucky
 
Last edited:
Register to hide this ad
Bucky Badger said:
Hey guys and gals. I have the opportunity to pick up a pair of Infinity Quantum Line Source Speakers for a REALLY good price and before I jump off the deep end, and drive 5 hours one way, I was hoping to get some of your opinions. I know that they require a lot of clean power and have read what I can find on the net but wanted your opinions on how they sound and any other info you might have. I would be buying these from the original owner and he told me they are in 9.8/10 cosmetic condition as well as all the drivers are working without any trouble.
Anyway, thanks for your time and I wish you happy music.

Bucky
Click to expand...

You're kidding me right? I'm picking up a pair of QLS-1's this evening after work! Infinity Karma at work?!
 
Hi CarnahanBB, thanks for the response. I would be GREATLY interested in what you think of them after you get them set up.
BTW, the wife is from Lincoln. Good state Nebraska.
 
Here is some information:

http://www.bobbyshred.com/infinity/QLS.html

http://www.infinity-classics.de/models/Quantum-series-1976/index-Quantum.htm

It has been over 30 years since I have heard a pair, but I thought they sounded great at the time. They take incredible amounts of power to work well, so make sure you have a very powerful amplifier (or amplifiers, as they can be bi-amped) to use with them, measured in hundreds of watts into 4 ohms.

You will also need a large vehicle to get them home, and two strong people to carry them. I believe they weigh 190 pounds, so I hope you have a strong back and a friend with a strong back.
 
Hey Bucky Badger! I will follow-up once I get them set-up but final judgement may largely be dependent upon amplification as my Quantum 3's soak up watts like a sponge and I'm 100% certain these will be worse. I think I read once that the efficiency level is somewhere around 80 db/watt/meter or something like that! Keep in touch!
 
I love mine, don't think I could ever part with them. Things to look out for are:
broken tinsel wires on the midrange domes
no sound from some of the EMIT tweeters
rotted foam surrounds on the Watkins woofers

If you get no sound from the mids, EMITs or midbass drivers in the entire cabinet, fiddle with the pots on the back, they are particularly susceptable to corrosion. Cleaning them properly requires removing the woofers to access the crossovers, removing the pots from the back plate and opening the pots to clean them with deoxit and a toothbrush. But you may be able to get the drivers working at least intermittantly by turning the knobs.

For normal listening you'll want 200 watts per channel into 4 ohms with a high current amp or amps. They were rated at 81 db / 1 watt / 1 meter.

I've archived several threads about refurbing QLS's if you need them. They're awesome speakers and I found it to be a labor of love to bring mine back, thanks to the assistance of AK members.
 
jimreeves said:
I love mine, don't think I could ever part with them. Things to look out for are:
broken tinsel wires on the midrange domes
no sound from some of the EMIT tweeters
rotted foam surrounds on the Watkins woofers

If you get no sound from the mids, EMITs or midbass drivers in the entire cabinet, fiddle with the pots on the back, they are particularly susceptable to corrosion. Cleaning them properly requires removing the woofers to access the crossovers, removing the pots from the back plate and opening the pots to clean them with deoxit and a toothbrush. But you may be able to get the drivers working at least intermittantly by turning the knobs.

For normal listening you'll want 200 watts per channel into 4 ohms with a high current amp or amps. They were rated at 81 db / 1 watt / 1 meter.

I've archived several threads about refurbing QLS's if you need them. They're awesome speakers and I found it to be a labor of love to bring mine back, thanks to the assistance of AK members.
Click to expand...

Teach me! HaHa! I'd love to see some of the threads as there is not much information about them out there (probably due to the fact that Infinity only produced approximately ~ 1300 or so pairs. I'm leaving work in 30 minutes to go pick mine up and I am literally ready to jump up and down! :banana:
 
That Emotiva should do just fine.
As far as how they sound, ample controlled deep bass (absolutely no sub required), clear detailed highs with no fatigue, beautiful clarity in the midrange, wide and deep soundstage, and little bit warm. First speakers I've owned that get effortlessly loud without seeming loud, until you have to shout over them to be heard! Equally balanced and clear whether you're in the sweet spot or 70 degrees off axis. May be too much for smaller rooms though.
 
CarnahanBB said:
I'm not trying to steal this thread but would a Pro Amp be okay to use? I've also been looking at this fella!

http://emotiva.com/xpa2.shtm
Click to expand...

Yes, a quality pro amplifier is fine to use instead of one made for home use. Just make sure it is a good one, and that it has appropriate connections for your other gear (keeping in mind that adaptors may sometimes be used). However, with many pro amplifiers, they use fans for cooling, and with fans, there is fan noise (i.e., one can often hear the sound of the fan itself, not through the speakers). Pro amps often use fans for cooling instead of massive heat sinks, because many pro amps are made to be portable, and fans weigh far less than heat sinks. Also, the listeners are often too far from the amplifiers to ever hear the fans.

However, there are some high powered pro amplifiers that do not use fans. The Crown K2 would have no trouble driving them.

I have heard good things about Emotiva power amplifiers, and I would guess that the one you have in mind would be adequate to drive the Infinity QLS. Infinity recommended an amplifier that puts out 500 watts.
 
Last edited:
Here are most of the links...
http://www.audiokarma.org/forums/showthread.php?t=215773
http://www.audiokarma.org/forums/showthread.php?t=166374
http://www.audiokarma.org/forums/showthread.php?t=269529
http://www.audiokarma.org/forums/showthread.php?t=115775
http://www.audiokarma.org/forums/showthread.php?t=276032
http://www.audiokarma.org/forums/showthread.php?t=269627
http://www.audiokarma.org/forums/showthread.php?t=261608
http://www.audiokarma.org/forums/showthread.php?t=36275
http://www.audiokarma.org/forums/showthread.php?t=71339
http://www.audiokarma.org/forums/showthread.php?t=87469
http://www.audiokarma.org/forums/showthread.php?t=311999
http://www.audiokarma.org/forums/showthread.php?t=303400
http://www.audiokarma.org/forums/showthread.php?t=333757
http://www.audiokarma.org/forums/showthread.php?t=317580
http://www.audiokarma.org/forums/showthread.php?t=341905
http://www.audiokarma.org/forums/showthread.php?t=352288
 
Last edited:
Thanks for the info guys. Looks like I will try and go see them tomorrow or Sat. If they are as good as the seller says they are I should be bringing them home with me. I will look forward to hearing your impressions on your new QLS's CarnahanBB.
Congrats and WoooHooo.
:banana:
 
With all this talk of power I hope my little Phase Linear 400 will do for the top end and my Crown D150A will work for the Watkins.(at least for the time being)
I have a Phase Linear 700B in the shop right now and will put that on the top when it's ready and the 400 on the Watkins.
:scratch2:
 
Those speakers were the cats meow when I first got into audio. Very nice speakers, would be tough to go wrong.
 
Bucky Badger said:
With all this talk of power I hope my little Phase Linear 400 will do for the top end and my Crown D150A will work for the Watkins.(at least for the time being)
I have a Phase Linear 700B in the shop right now and will put that on the top when it's ready and the 400 on the Watkins.
:scratch2:
Click to expand...

You might want to reverse that strategy, as the woofer needs the most power according to this review:

Page 1:

http://www.infinity-classics.de/mod...Quantum-Line-Source-QLS-1/QLS_1_Review_01.jpg

Page 2:

http://www.infinity-classics.de/mod...Quantum-Line-Source-QLS-1/QLS_1_Review_02.jpg

You may need to click on the pages to get them to enlarge enough for you to read the article.

Interestingly, they say the speakers are only 150 pounds, when an Infinity brochure claims 190 pounds:

http://www.bobbyshred.com/infinity/QLS.html

One of them is probably just be a misprint.
 
:tresbon::tresbon:
I can highly recommend them.
I'd rate them a better speaker than a couple renowned vintage speakers I own, like the ADS L-1530, KEF 104/2 or the Spendor SP-1 just to name a few:)

I would not recommend them for a small space though.
 
Last edited:
In the house! Here is a picture of mine at the moment...spoke with Bucky Badger tonight and it sounds like there will be two more QLS owners on AK! :banana:
 

Attachments

  • IMAG0397.jpg
    IMAG0397.jpg
    63.6 KB · Views: 188
You must log in or register to reply here.
Back
Top Bottom