Another QLS-1 thread

Yes these are very worthy speakers to fix and not part out. I never thought the Quantum series looked that great in pictures as compared to other infinities. In person the cabinets are very nice, of good quality and just massive. Much more of a pain to work on though.
Jim
 
Before re installing, check out the pots with your multimeter to make sure they are working to your satisfaction, if you haven't already done so.
Have Fun.
 
I now have one speaker functioning properly. Added some polyfill in the bottom of the cabinets, re terminated some of the mids. Also added four more screws to hold on the woofers. Only came with four from the factory. Drilled through the ring and baffle and used 8-32 t nuts.

All the tweeters work in the other speaker which is a relief. Don't have to unsolder the array. Just need to clean up the pots and re terminate some of the wires for the mids, (Both speakers had some of the little tabs broken off the mids so I had to make new ones.). After that I'll need to clean up these cabinets to make them presentable. It would be good some day to make new bottom bases as these sat in some water at some point and have a ring around them. There's some warped veneer on one base too.
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Out of curiosity, It would be cool if you could measure the tweeter and mid arrays out of circuit.
 
Both the tweeter array and mid range both measure 5.5 ohm. Not sure what they should be but that's what mine measure. This done by removing the wires from the posts and measuring at the ends of the wires with no crossover components interfering.

Could someone tell me what their impedance measures at the back plate terminals. Both independent high frequency and low. Thanks.

Have all the pots cleaned, plate remounted and the mids all back in the second speaker. Just need to measure out my polyfill and replace the woofer in and add those 4 "t" nuts to the baffle. Probablely not going to rebuild the crossovers at this point unless I see or hear a problem. Funds are tight. Everything I have tested so far on the boards is satisfactory.
Jim
 
T-nuts are a good idea.
The tweeter array should measure around 2.85 ohms according to this wiring diagram:
I had to rewire mine and ended up measuring 3.1
Twtckt (1).JPG

The mid array measured 3.9 ohms.
 
Thanks, I saw that in an older rebuild thread which was very helpful. Hmmm, I wonder why mine are so high. I guess they will not play as loud as they should. I will try and look for one measuring high. I will listen to each one again and try and find the bad one. They all play unlike the other speaker so I did not bother to remove them.
 
Well, these things are kind of kicking my a$$. Removed the tweeter array because of the total impedance being too high. Found three that were measuring high. Re flowed the solder buttons and tahdah, they go back down from 11ohm to 5.2 on each one. Than re soldered the mess back together and the array is 3.2 ohm. Not perfect but I will live with it. One tweeter had the magnets flaking badly. The dispersion slots had black dust all around it. Should have taken a pic but I was already having enough trouble. All the time I'm listening to my 2.5 's and thinking what's wrong with them, sound pretty freaking good, why mess with a clapped out pair of 40 year old speakers just enjoy these.

To find the bad tweeters I listened to each one with a nurses stethoscope. If you really concentrate the bad ones stick out from the rest. Could not hear the differences with an empty paper towel tube. The array is back in but not screwed down yet. Maybe finish it up tomorrow.
 
Little less frustration tonight. Sealed up the leaks in the base of the cabinet and tweeter wire holes with silicone. Everything in speaker number two is in place except for the woofer. Didn't even strip any of the holes out when tightening the tweeters and mids down on either speaker. Measured out my poly fill to the same volume as the other speaker so that's ready to go.

Listen just to the high end for a while. The mid ranges are a very nice sounding driver. The tweeters are effortless with all eight splitting up the duties. Once I get them together and as long as both speakers sound and measure exactly the same I will put them to work with my robust Philips 578. That amp has the biggest power supply I have ever encountered. No idea of the rms at 4 ohms but has to be over 300. Drives the 2.5's and doesn't break a sweat. Very good slam. I've been using it and the 572 preamp in my main system for most of the year with several different pairs of speakers with very pleasing results.

Not really sure how I'm going to move these things. May set them up in my basement for now. My main room has far too many speakers in it. Did send off my DQ10 I freshened up and a real nice pair of DQ8's to a fellow Aker. I would buy another pair of hammered dq10's if the price was right just to fix them up. Very easy speaker to work on and sound amazing when working properly.
Jim
 
what woofers are those...?
They are a custom rebuild from Millersound. Reused the basket, magnet and coils. New surround, spider and RDM fiber cone. He tells me he got a full 1 inch of travel out of the cone. They are a delight to behold. Just a work of art. If you check out page one there are a couple of pics.

I was going to just replace the surrounds but the cones were pretty crispy and had plastic cement all over them.
Jim
 
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I have the speakers in my upstairs stereo room. First impression is very good. All the qualities of classic infinity, nice tight bass and liquid midrange. The sound is huge, far bigger than any of my other infinities. Also I am pleased with the results in my small room. Pretty much all I have in the room is my gear and a chair so they can be placed anywhere. They would be better in a large room but I never experienced the image I get with these in my space. The line source of tweeters and mid ranges may be the answer. I must sit in front of them more to say if I like them better then the others I have. Also, I was told the woofers need to play for 50-100 hours to sound their best. They sound pretty darn nice now.

When the holidays are over I will have more time to play with position and listen more. I will post then and put up a couple pics.

I almost hate to take the grills off again. (They may just fall off) Hard to believe they couldn't come up with something better. I may make felt covered button magnets and some steel pieces to place on the speakers instead of those silly plastic things. (Being a machinist comes in handy at times) That is one non original alteration I feel would be worth the trouble and not do harm the value.
Have a safe New Years Eve!
Jim
 
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everyone bitches about that grill design...mine fell off my Q2's and almost took out a dome...
 
Yes, I know what you guys are talking about. I imagine the post type grill mounts are even worse. Mine are the older ones with the plastic things mounted on the cabinet with no post. There's a couple of those little plastic teeth bent over keeping them from all locking in. They were probably great when new or at least better.
 
Jim, I did not know you just finished them. You have done a great job with them!! After seeing yours together makes me want mine back up and running bad. The stolen mid's was one hell of a set back, but nothing that can't be overcome in time. Thanks for your help Jim, You are the man!!!
 
Well I have had a few hours to play around with these the last week or so. I really really like them. I'd say my favorite Infinity I have. The Emim can be a little hot for me at times even with the Graz replacement diaphragms in the IIb's.(sorry, the IIb's are NOT for sale;). The QLS1 midrange is huge with very nice separation of the instruments. Acoustic bass sounds very balance through out the scale. As does piano. Horns sound very life like. Voices like that of Eddie Vedder can sound annoyingly metallic in some speakers sound far nicer in this midrange. Johnny Cash's American recordings from the '90's are spooky good. Not a bad rock in roll speaker either. Bass is quite good, the Millersound rebuilt woofers are amazing. I tried to play some very bass heavy electronic music to see if these woofers would bottom out and it hasn't happened even though these have the first generation crossover. I think I will leave it alone as they sound and measure identical. Only thing I might do in the future is add some bracing in the cabinets near and just above the woofers.

These were a lot of work and fuss but I would do it all over again. The drive, the price, everything. My OCD gets the better of me though as I am always checking to make sure all the drivers are still working...

Thanks to ALL who have so well documented their work on these speakers here at AudioKarma. So many great rebuilds, pictures and tips. I would not even know where to begin on these without them. They are really a special speaker and live up to their reputation once properly working again.
Jim
 
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