:banana:

There may be a light at the end of the tunnel, and hopefully it is not an oncoming train........

For anyone who is interested, my QLS-1's are up and running. Attached photos show some of the work and improvements on the speakers. Here is what has happened so far:

- Got the woofers re-edged at Orange County Speakers. Great service, quick turnaround. 39 bucks per woofer + shipping and tax came to just over 100 bucks. Round trip in less than a week!

- While the woofers were out on holiday I took all six pots out for a little checkup and cleanup. They were very corroded. Attached photo shows one of them disassembled before being removed from the cabinet. You can see the corrosion especially on the case that is in the background on the left side of the picture with the green wire right in front of it. This was before I detached it and took it out. Total of three pots per speaker (tweeter, midrange, & midbass) were unsoldered, taken apart, cleaned up with sandpaper and squirted with some contact spray. The soldering was a bit tricky as I was working with both hands inside the cabinets at a somewhat awkward angle, but I got through it. The results were really amazing. There was noticeably better response in the tweeters especially and also the mids. Also the pots were very noisy when adjusted and cut out completely at certain points. Not any more! Now they're like butta....:yes:

- New amps. I ended up choosing a matching pair of Adcom GFA 555's (see photo). They are rated at 330W / ch into 4 ohms. I have a dedicated amp for each speaker in a vertical bi-amp configuration. I got some swanky new shielded patch cables ($80) that split the pre-out signals from the preamp. The left pre-out is split into two cables with the resulting pair patched into Adcom #1 operating in stereo mode, with one patch cord into the left channel, one into the right channel. Then the outputs of Adcom #1 are wired with the left channel powering the bass on the QLS left speaker, the right channel powering the mid-high of the QLS left speaker. The right pre-out is also split into both channels of Adcom #2, with the left channel again powering the bass and the right powering the mid-highs of the QLS right speaker. No active crossovers are used, just the passive crossovers that came with the speakers. Some people claim an active crossover is superior, but Infinity recommended the vertical bi-amp with the passives back when the speakers were manufactured. :scratch2:

- Changed the mid bass couplers. I thought I needed to but it turns out I was wrong. The right mid bass was buzzing and I thought it was bad. This was before I cleaned the pots. I found another pair of couplers, installed them and the right one was still buzzing. Cleaning the pots almost eliminated the buzzing. It still buzzes a little bit at high volume. This is still unresolved. I'm thinking I may have an issue in my right crossover, but I don't know how to trouble shoot this. The pot cleaning improved the buzzing a lot, but it did not eliminate it. :scratch2: I turn the right mid-bass pot down and that also helps. (and now I have an extra pair of mid bass couplers to save for a rainy day)

So that leaves the pre-amp as the weak link in the chain. After fuzzing out my old Yamaha receiver I went to a backup. It is a 1978 Marantz integrated amp, and I am utilizing it as a preamp. It is less than ideal, but will have to do until I find another preamp or preamp / tuner.

The sound quality is incredible. I am still auditioning various recordings and trying to adjust the QLS-1's for my room. I listened to Verdi's Requiem to see how the woofers would stand up to the quadruple fortissimo timpani sections, and I was quite impressed. The Adcoms seem to be up for the challenge as well. They are very clean with a lot of headroom. I finally have the kind of volume I was looking for in the QLS-1's. I daresay they could handle a pair of 500 W / ch amps with ease. Probably more.

Thanks to all who gave me tips and advice. I'm still pondering that right midbass coupler. But the speakers are workin' pretty good for their age.

Awesome tlgibbs. But your audio reviewer skills need some improvement :D

About the midbass buzz. Need to determine if it is a mechanical vibration due to overall speaker resonances or specific to the midbass itself. Turn the midbass pots all the way to one side (forget which way it is) and the driver will be cut out completely. Run up to the volume you normally hear the buzz, and see what happens. If the buzz still occurs, then you know it is not in the crossover (can't think of what a crossover could be doing to create a buzz, but never know I guess :scratch2:) or from the action of the driver being powered, but that it is a simple vibration from something loose in the area.

An area I'ld look at is where the midbass wires go through the hole in the tube. I packed that with rope caulk on mine. The wires could be vibrating in the hole if loose. Check that the tube itself is not a bit loose.

If the buzz goes away.....well, have to think about that on a fresher brain, it's late now in the east :yes:

See ya. Nice to see a QLS-1 working and being enjoyed:thmbsp:

That's sweet!

Do you maybe have an overal picture of the X-over? Because when I see that 1 picture I'm affraid of opening ours to fix the Potentiometers and the caps...:scratch2:

Btw, how would you describe the high of the speaker?

Ok, I am no expert by any stretch of the word. I pulled the pots at Kencat's urging and going into it I was a bit apprehensive. I looked at the crossovers and I saw a bunch of wires and thought, "oh s*#@", what am I getting myself into? But after studying the wires and the wiring it really isn't all that complicated. I had a schematic but didn't really use it. The pots are really simple. They had two wires soldered onto terminals on the back of each pot. One pot on mine had three. Before desoldering I took a digital picture of the wiring so I could be certain I wired it back correctly. I also wrote down which wire went to which terminal just to be extra sure. The pot is held to the speaker cabinet with a simple flat threaded washer on the exterior which is revealed when you pull the little black plastic knobs off the back next to the binding posts. These are the adjustment knobs you use when you adjust the pots. Once the washer is removed you have to dislodge the pot from the cabinet. Mine were stuck because of the corrosion. They came off with a little coaxing. Depending on the position of the pot and the angle that it is at, you may want to remove the wires before loosening the pot itself. Most of the wires were easier to desolder while the pot was still attached and stationary. Desoldering is easy. Just take the point of your soldering iron and heat up the solder until it liquefies and the wire comes loose. Sometimes you have to push the wire around some to get it out of the terminal hole, depending on the angle and whether the tip of the wire is curled around the terminal. Just keep working it. You have to be careful that you don't accidently get the soldering iron too close to other wires! You don't want to accidently melt another wire that is minding it's own business! Just be deliberate and clear the wires out of the way by gently pushing them to the side. This is also a good time to check all the other wire connections in the crossover and make sure all connections are good and solid. After the pot comes loose and you have it out you will have to work the solder some more on the terminal posts so you have a nice big clean hole where the wire went. Try to get the hole as big and clean as possible as this will make reattaching the wires through the holes easier. After the pots are out of the cabinet they are quite simple to dissassemble. Mine were very corroded and stuck together in places. There is a wire clip that holds the pot together. It pops right off. You just carefully work the parts until they all come apart and then clean everything up. You may want to take a picture again if you are nervous about getting them back together right. I used 120 grit sandpaper, little squares of it, for most of the crud removal. When you get the pot apart it is pretty obvious how it works. You just make sure that all the conducting surfaces are cleaned of any crud and corrosion. Mine were so bad it is a wonder they passed any current at all. After reassembly I sprayed everything with contact cleaner.

How do they sound? In my case it made a world of difference. The tweeters especially are much brighter. The speakers sound clearer, cleaner and more sparkling. I can hear cymbals much better. To my ear it sounds like I put a new set of tweeters in. It made that much difference. I don't think everyone can expect that dramatic of a result, however. Like I said, my pots were really bad.

There was one pot that was the most challenging of the three. It had three wires connected to it instead of the two wires like the other pots. One was a very stiff wire that was just long enough to reach the terminal. The pot was also at a weird angle to be working on from the access through the woofer hole. When I reattached the wires I had to do them in a specific order, with the pot tightened in one position for the first two wires, then loosened and turned a bit further to bring it into positon to receive the third wire, which was pretty much in a fixed position. It was a little tricky.

I had never done anything like this before, but I guess I have some aptitude for this kind of work. It is somewhat daunting at first, but once you get the hang of it, it's really not that complicated. Oh yeah. I took each pot out one at a time rather than removing all at the same time. That way you only have a couple loose wires at any given time, and there is less chance of getting wires mixed up.

I'm sure there are others in this forum that have a lot more experience with cleaning pots than I do. I maybe should have taken more pictures when I was doing the procedure, but I really don't feel qualified to position myself as any kind of teacher. I have never done this before and was learning as I went. But I have to say it was well worth the effort. I spent two evenings and probably a total of 4 hours on this project. Good luck!:thmbsp:

Do you maybe have an overal picture of the X-over? Because when I see that 1 picture I'm affraid of opening ours to fix the Potentiometers and the caps...:scratch2:

Btw, how would you describe the high of the speaker?

Bunny,


Pics of the Q2 xover. I think the QLS has the inductors on the bottom board, with the pots and caps and resistors on the back panel board. The components of the Q2 are basically identical to the Q1 from what I've seen. These will give you some idea of what you'll find.

http://www.audiokarma.org/forums/showthread.php?t=57265&page=3 last post.

I had to cut the plastic spool of an inductor to get one of the pots out.

http://www.audiokarma.org/forums/showthread.php?t=63726 post #8

http://www.audiokarma.org/forums/showthread.php?t=92098 some pot pics here too.

QLS 1 pics here but perhaps after being redone: http://www.audiokarma.org/forums/showthread.php?t=91718

Nice story, and good descriptions of the stuff you had to go through to get these classics singing again. :thmbsp:

Kencat - I checked the pictures on your thread when you had your pots out. They are identical to mine. Yours were even more corroded than mine. Question: As I turn my pots up and down they don't seem to make an audible difference in the respective levels of the midranges or the tweeters. At least I can't hear any difference. Shouldn't there be an audible difference between minimum and maximum on the pots? I was careful to reattach them exactly as they came out of the speakers. Can you think of a good way to test them to see if they are working correctly? Or at all?

tlgibbs,

The change is indeed subtle. But there should be a change. What about turning down two of the pots, then play with the other one to see if you can hear the change better. Repeat this for each one.

You could check the resistance across the pot using your multimeter varying the shaft from max to min. Make sure the speaker wires are disconnected. Check the schematic that you aren't measuring across a different circuit. PITA to pull the woofers again though.

I checked mine while they were out after cleaning, and the resistance did change quite linearly.

Anyone else with Q's that experience the same minimal audible change?

I don't hear a diff with my IRS1.5"s. And checked them; Tweeters open, nope, no extra high, mids open, nope, no extra mid. Sometimes I think I hear a difference but I think I just WANT to hear a difference.

Just a observation. I dont know if the pots control the volumes for each speaker. I think it changes the crossover point for the speakers. If you increase or decrease the resistance of a driver via pot, wont it change the crossover points?

Nope. A resitance has nothing to do with the Xover point. It just turns power into heat in stead of sound...

I downloaded an audio test tone cd last night. The link is here

http://binkster.net/extras.shtml

I downloaded the whole cd and burned it just in case I ever need it, but what I was really after was track 58, which you can download by itself if you wish. I turned on the pink noise and got a nice hiss through my speakers. I turned the pots all the way down as well as the bass control on the preamp and isolated each speaker with the balance control. I then took the tweeter pot and went from min to max and back and forth several times. There is indeed a difference. I had to listen very carefully to only the high end of the pink noise as I adjusted the pot, and there was a noticeable increase and decrease in the tweeter response as I adjusted the pot. Ditto with mid. It is as you say Kencat very subtle. My ears are not trained enough to notice this in recorded music. I guess it takes some kind of practiced listening to be able to discern these subtleties. But at least I know that my work on my pots was not in vain. :thmbsp:

Just a observation. I dont know if the pots control the volumes for each speaker. I think it changes the crossover point for the speakers. If you increase or decrease the resistance of a driver via pot, wont it change the crossover points?

Nope. A resitance has nothing to do with the Xover point. It just turns power into heat in stead of sound...

Another great set of comments to stimulate the learning experience :D

From my basic understandings of crossovers, and from doing a bit more research , I would agree that putting a series resistor (or simple potentiometer) ahead of a driver will change the crossover point. It will also attenuate the driver output the higher the resistance value. The argument for this is that if you look at a crossover table for the values of caps and inductors, the values are different for a given desired crossover point depending on the drivers' impedance. So, if you insert a series resistor between the crossover and the driver, you have now just changed the drivers' impedance as seen by the crossover, hence the crossover point will be shifted. (This is also implied in the following article: http://sound.westhost.com/lr-passive.htm#s6.0)

NOW, the question I have with this is whether the position of the added resistor or pot, wrt the crossover circuit elements, makes a difference. I believe the answer is also given in the above linked article, and I will take the position that if the attenuator (resistor or pot) is placed before the crossover circuit, then the crossover point will not be changed. As stated by Rod Elliott though, this is a huge waste of energy, increasing power requirements of the amp. It seems Infinity didn't care about this as discussed below.

Looking at the QLS-1 schematics, the pots for the mid-bass coupler and tweeters are ahead (or behind depending on the AC signal) of the crossover elements, so the pot should not be changing the xover pt. The midrange drivers have the attenuation device between the driver and the crossover elements, BUT, this "pot" is actually wired in as an L-pad (from what I can see), which presents a constant load impedance to the crossover and therefore will not change the xover pt. So, it would seem that Infinity took care of the potential change in xover pt due to some proper design (some of it improper per the article above :D).

I would like some more confirmation though on the "positioning" of the attenuator if any readers have more info on that :yes:

I downloaded an audio test tone cd last night. The link is here

http://binkster.net/extras.shtml

I downloaded the whole cd and burned it just in case I ever need it, but what I was really after was track 58, which you can download by itself if you wish. I turned on the pink noise and got a nice hiss through my speakers. I turned the pots all the way down as well as the bass control on the preamp and isolated each speaker with the balance control. I then took the tweeter pot and went from min to max and back and forth several times. There is indeed a difference. I had to listen very carefully to only the high end of the pink noise as I adjusted the pot, and there was a noticeable increase and decrease in the tweeter response as I adjusted the pot. Ditto with mid. It is as you say Kencat very subtle. My ears are not trained enough to notice this in recorded music. I guess it takes some kind of practiced listening to be able to discern these subtleties. But at least I know that my work on my pots was not in vain. :thmbsp:

Using the pink noise was a great idea. Glad you shared that with us. It would give a constant signal to use, thereby making it easier to discern a difference. :thmbsp::thmbsp:

Hey tlgibbs,

so what do think of the Q1's so far? compared to other speakers you've heard.

You should be hearing some pretty amazing bass - deep, tight, not overbearing but you know its there type bass.

What a nice read. I'm glad to see another pair of classic Infinity Speakers back in good form. I always wanted the QLS 1 back in the day, however my budget at the time only allowed for Quantum 5's......and they served me well for the better part of 10 years.

Enjoy those QLS1's and let us know how you like 'em after you listen for a while.

Best,

Paul :thmbsp:

How would I describe my listening experience with the QLS? I guess I am learning to appreciate them more and more. I kind of feel like a wino that has been given a bottle of Chateau Petrus. I know it is good, but I have a lot to learn to fully appreciate it. Getting my amps was a good first step, I think. I look forward to adding other components as I am able. Listening to the QLS can be breathtaking. I have found that I am enjoying classical music more and more. The instruments from a recording of a string quartet sound like they are in my living room. I don't get distortion from my speakers unless the distortion is in the recording itself. Other speakers I have owned sound extremely colored in comparison. Yes, they get very loud with my Adcoms, but they are so extremely clean.

About the bass response. Since getting them refoamed I swear the bass sounds tighter (possibly a psychoacoustic rationalization!) I have never personally heard bass like the bass I hear in the QLS. Very few of my recordings really tap their potential, however. When called on for a really low frequency they respond like no other speaker I have heard. I'm sure there are better ones out there, but my Watkins woofers provide all the (accurate) thump I need.

I'm really not sure what to do with all the tone controls and crossover adjustments on the speakers. I read a review of the QLS that was written in 1977 where the reviewers spent the better part of a morning adjusting the tweeters, mids and mid bass as well as the crossover points on the tweeters and then choosing a position for the speakers themselves relative to the walls of the room. My aptitude in this area is simply not that developed. Remember I wasn't sure my pots were even working! After reading some of the posts in this forum I realize that from a technical standpoint I am like a freshman listening to a group of Ph. D's ruminate about esoteric subjects that I only hope to someday understand more fully. But you have to start somewhere. I guess I'm lucky to have a speaker system that is still fairly well regarded.

And I just love to show them off!!:yippy:

:D

This is cool. Your listening impression mirrors mine when first listening to the Q2's. I was underwhelmed at first. The expectation was that my socks would be blown off, but instead I was sitting there with my hand rubbing my chin wondering what was I hearing. I knew it was unlike what I'ld heard before, and yet some stuff was not so good, while other pieces were wow! It took awhile to realize I was hearing the recording for it was.

And yes, the bass is also so revealing. When it is there in a recording it is there, as subtle as it was intended to be or as bold as need be. And to me it is fast.

Pretty soon you'll be searching out recordings known to be excellent, especially for their bass content, and just for their clean overall production. There are some threads on AK that discuss various music members use to "test" their systems....very cool reading:
http://www.audiokarma.org/forums/showthread.php?t=81388&highlight=test+records
http://www.audiokarma.org/forums/showthread.php?t=82131

Steely Dan - Aja was a very popular one, and I recall discussion about various versions of CDs that were better and worst. I've been listening to some A.C.T. that has some super low bass that makes your body shiver when it comes on.

And then there is vinyl........these speakers were made in that era, need I say more? Now you'll have to frequent the Turntable forum to learn all about that ancient but fabulous technology :yes:

I would use the test tone to trouble shoot the mid-bass noise.
If you can find the exact frequency that porduces the noise, you can determine if it is mechanical noise or if it is in one of the Xover components.
Very hard to do with music since it is so on and off.

Ok, I just tried something that I probably should have tried already. I took the mid bass coupler out of the speaker but left it hooked up. That is I took the screws out that hold it in place and laid the driver on a pedestal that was sitting directly in front of the speaker so I could listen to it without it actually being mounted. Guess what? No buzz. That tells me it is the tube or something connected to the tube or the connector wires that go through a hole in the tube. Not quite sure how to troubleshoot such a situation... :scratch2: Anyone have any ideas? Can the tube be detached?

Ok, I have isolated the buzz with a constant tone at 250Hz (good idea Banff). It seems to be the mid bass port tube. I can make it buzz consistently and when it does by pressing on the side of the tube it stops. So how in the heck do I detach and remount the tube?

By carefully inspecting the tube I notice that it is only glued on the side that is flush with the front wall of the cabinet. The back of the tube extends slightly out the back of the back wall of the cabinet but is not mounted in any way. It just kind of rests against the bottom portion of the port but there is a small gap on the top of the tube and the sides of the tube. What I need is something to wedge in there or some kind of gasket that could go around the tube to keep it from vibrating. But the gasket would have to be very thin and flexible and would have to absorb any harmonic vibration that is causing the buzzing. Any ideas what I could use as a gasket or shim?:scratch2:

Why not use the white glue that is typically used to attach the foam surrounds to the cone and basket?

Tacky glues is what I know them by. Dry clear and retain gel-like. Should be perfect for this. Found in craft shops ?

Oh. My. God. Imagine Homer Simpson right now hitting his forehead and saying DOH!!

It was not the tube. First I tried putting some thin cardboard coasters between the tube and the edge of the hole and still the buzzing persisted. Then I stuck my hand through the port and grabbed the back of the driver. Buzz gone. Hand off, buzzzzzz. Hand on, silence. Hmmmmmm......:scratch2:

So I take my wrench and tighten the mounting screws down TIGHT. So tight I thought I was in danger of stripping the wood. No more buzz!:banana:

I've been told I have a screw loose but this is ridiculous.... I mean, the screws were tight, but I was hesitant to really torque them for fear I might strip the particle board holes. I can't freakin believe that was all it was. But it seems like there should be some kind of gasket between the metal of the driver and the wood cabinet. That would also eliminate the buzzing. :wtf:

So once again, check the obvious stuff first........... (still kind of weird that it only buzzed at 250 Hz...)

(still kind of weird that it only buzzed at 250 Hz...)

R.E.S.O.N.A.N.C.E.

You're right though tlgibbs, probably would be best if there was a foam, rubber, or cork gasket under that mid-bass driver. Should be a worthwhile mod :yes:

Yes it would be a good mod. I'll have to find some material and make a gasket..........

However, in the meantime, (drumroll, please)

I do believe (knock on wood), I have addressed and resolved all major issues pertaining to my vintage Infinity QLS-1 speaker system! :rockon::guitar:

Kencat, if you were here I would buy you a beer or cocktail of your choice!:beerchug:

Now, the only thing left to do is listen to and appreciate these fine speakers.:rockon: Little did I know the odyssey I would undertake when I acquired these just this past August. But it has been an interesting, educational and ultimately rewarding trip. I have a pair of conversation pieces in my living room that I will gladly tell anyone who is interested the entire story from acquisition to completion. The only project I could do at this point is to restore the original woodgrain cabinets. The previous owner painted them flat black and they look fine. If you didn't know they were originally wood you probably wouldn't suspect. Very long and labor intensive project, however. For now I think I will just enjoy them and try to figure out how to adjust the pots for the best sound..... :yes:

:thmbsp::thmbsp::thmbsp:

Thank you tlgibbs. :beerchug: back atcha.

While you are are enjoying the music though, ponder this future project to make those Q1's look like these - http://www.infinity-classics.de/infinity/models/Renaissance-series-1992/Renaissance-90/Renaissance_90_10_1.jpg

That would look incredible :yes:

I'll take a crown & 7
Just a matter of using the tools you have to solve the prob.

am new to ak....wound up here seeking info on how to repair the highs in my QLS speakers...Have had them for a long time and never caused me much trouble. The highs all went out in one of them. I bet that a cleaning of the pots as described so wonderfully by you guys will be just the trick. Thank you! Nice project for some bad weather day..commin up soon. Am a bit leary but hopefully all will be fine

Make sure to make notes before you take anything appart. It is very annoying if you make everything lose and seperate it and when you want to re-assemble it you notice that your caps and resistors have a differente value then on the schematics you find on the web :no:

And if you do,t ake a lot of pics and show them to us :D

Kencat - Could a bad pot cause all the tweeters to go out at once? That doesn't make sense to me. It would seem like a pot would get dead spots and become noisy, etc., but I wouldn't think it could cause all the emits to go out at once. Any thoughts?:confused:

Re: the gasket - I seat my drivers in black silicone and screw down nominally firm. Never had one buzz and it's easy enough to pull the driver if need be. Silicone does not break free under vibration, only under constant one directional tension. Pulling a driver just means slow steady pressure and it'll pop right out. Sound is two way street, so it's a good mounting and dampening material :)

am new to ak....wound up here seeking info on how to repair the highs in my QLS speakers...Have had them for a long time and never caused me much trouble. The highs all went out in one of them. I bet that a cleaning of the pots as described so wonderfully by you guys will be just the trick. Thank you! Nice project for some bad weather day..commin up soon. Am a bit leary but hopefully all will be fine

I would bet your tweeter pot is at fault it is easy to fix just get it out of the speaker and then take it apart real easy. They get rusty from the heat and then then condensation from playing the speakers. Yes an open pot in this circuit would take out all the tweeters as it is in series with the main input for the tweeters all current flows thru this pot for the tweeter circuit.

Jerry

Re: the gasket - I seat my drivers in black silicone

Great idea. That will be on my to do list. BTW, I hadn't noticed it until I played that 250Hz test tone into my speakers, but I could make both mid-bass couplers buzz, not just the right channel as previously heard. I wonder how many other QLS (or any model using the same driver) owners have heard the same thing and not realized what it was........:scratch2:

thanks! you guys are cool........will let you know how it goes when I get brave enough to do the operation )))

By carefully inspecting the tube I notice that it is only glued on the side that is flush with the front wall of the cabinet. The back of the tube extends slightly out the back of the back wall of the cabinet but is not mounted in any way. It just kind of rests against the bottom portion of the port but there is a small gap on the top of the tube and the sides of the tube. What I need is something to wedge in there or some kind of gasket that could go around the tube to keep it from vibrating. But the gasket would have to be very thin and flexible and would have to absorb any harmonic vibration that is causing the buzzing. Any ideas what I could use as a gasket or shim?:scratch2:

Tlgibbs
Do you have a picture of the rear port where the midbass exits.
From your description, mine are totally different. The one's I have do not extend from the back of the cabinet. They have a circular speaker cloth cover that is flush with the back of the cab. Not sure perhaps some differance between different models of the qls. I can tell by looking at the back of the tube, that it has never been modified because the glue used to hold it in place looks very old.

I am sure if you were carefull, you could completly remove the tube, clean it up, and re-glue the whole piece back in. I probably will not touch mine unless they are making some type of noise. I am only a couple days away from testing the one I have completed. It is totally finished except for 5 standoffs needed to mount the Xover circuit board. I will use my laptop as a signal source
and set up a slow sweep (40sec) from say 15hz to 20kz and listen for any strange sound that should not be there.
Anyway, if you have a digital cam. take a few pictures. Would be interesting to see what the differances are.

Thanks

Banff

Your ports are almost identical to mine. I also have the grille and the grill cloth. The differences are that mine have no glue and they protrude slightly more out of the port hole than do yours. My previous description may have given the impression that they didn't have a grille. That is not the case. When I say protrude I mean from the recessed level that the grille rests against. You can't really tell from my picture but there is a small gap on the top of the port. It is just wide enough to get a flexible piece of cardboard through.

But as previously stated in the post, it is not neccessary to dismount and reglue these ports. The buzz was eliminated by torquing down the mounting screws on the mid bass driver itself. Had my ports been glued on the back the way yours are that probably would have eliminated the buzz as well. But there is no reason to glue them if I can eliminate the problem in an easier fashion, which I have done. :yes:

I do like the idea from BrocLuno of using black caulk to seal the driver to the cabinet. That will also help and most likely keep me from having to torque the mounting screws to a point where the particle board screw holes are in danger of stripping.:thumbsdn:

If yours are not causing you any issues I would leave them alone, seal the drivers and move on. :yes:

Have you actually heard your speakers yet? What are you driving them with? If there is one thing I have learned make sure you have a lot of watts and that your amps are stable down to a 2 ohm load (many are not). Otherwise the QLS will eat your amp like a foo-foo appetizer. :yes:

Wow
Thought I had the only black pair of qls's in the world.
Going to use a Onkyo M-504 for the initial test. I just want turn it up very loud. Starting at 15 hz I will take a bunch a data points all the way up to sya 10khz and plot out the impedance curve so that I can compare the newxover ckt to the old one. It will probably handle them at low volumes but i'd be scared to crank it up untill I know exactly what impedance I'am looking at.
Once I land a new job, I will probably buy a couple of amps for them.
Would like to have somewhere between 500 to 1000watts for each speaker since the sensitivity is horrible (81db 1watt 1meter)
Oh well guess we will see.

I would proceed very cautiously with that amp. I did a google on the m504 and found a review that cautioned against using it below a 4 ohm load. The QLS is unforgiving in this range. In order to drive the Watkins woofer it is imperative that the amp be stable down to 2 ohms. I fried a Nikko Alpha 1 that was not up to the task. The Nikko puts out over 300 W into 4 ohms, but it apparently also is not cabable of driving the woofers on the QLS. I blew the Nikko when it was driving both bass sections in a horizontal bi-amp config. This is not a recommended amp configuration, and I found out the hard way.

Infinity recommended two amps, one dedicated to each channel of the QLS in vertical bi-amp. I now understand why. Hooking an amp up to both bass sections can and probably did in my case literally suck the power dry. I was listening at moderate (10 o'clock on the volume knob) levels when the Nikko checked out.:cry:

It would be a shame if you also went down this path after all the work you have put into your speakers. (I checked your previous threads).

For my money the 2 Adcom GFA 555's are performing well and so far (knock on wood) seem quite stable. I chose the Adcoms because of a number of factors. They are stable into 2 ohms, they are built very well, they are readily available, and they offer great value for the dollars invested. I picked mine up for $400 apiece. One I found on Bay area craigslist (funny side story here if anyone is interested), the other on eBay. Both are absolutely clean, no nicks, scratches, etc. I also threw down another seventy bucks for shielded "y" patch cables to split my pre-out signals. With shipping and gas I have almost a grand into the amps and cables, but it was worth it to me. :thmbsp:

If you don't have the bucks right now for amps I would wait before firing up the QLS.:( That's my 2 cents worth.

am new to ak....wound up here seeking info on how to repair the highs in my QLS speakers...Have had them for a long time and never caused me much trouble. The highs all went out in one of them. I bet that a cleaning of the pots as described so wonderfully by you guys will be just the trick. Thank you! Nice project for some bad weather day..commin up soon. Am a bit leary but hopefully all will be fine

bondhere69,

Welcome, and :thmbsp: to being a QLS owner. How about a bit more on your ownership story? how long and who, what, where, when, and why??????

RE: the highs being out. Is it only the emits or also the mids and midbass? Can you get any sound at all when rotating the pots back and forth?

bondhere69,

Welcome, and :thmbsp: to being a QLS owner. How about a bit more on your ownership story? how long and who, what, where, when, and why??????

RE: the highs being out. Is it only the emits or also the mids and midbass? Can you get any sound at all when rotating the pots back and forth?

I got em when they were about 6 months old from my brother in law... He worked for the railroad ,moved frequently,and his wife was constantly complainin about em..:bash:the size etc... Was visitin one day said he was tired of listening to her witch and asked if I wanted to buy em:banana:..cost was $1000..:deal:..came with a couple of new emits and a new spare watkins,which is plastic the originals are paper(he was a bit extreme and planned on keeping them).... 6 months after that she left him anyway:scratch2: I have enjoyed them eversince. They are still in very nice shape but beginning to require a bit of pampering. Have an issue with the woofers(a story in itself) and now the crossover problem if that is what it is.

It is only the emits that are out....and I thought I had em on a couple of times rotatin the pots but wouldn't stay. Thanks for the interest

It is only the emits that are out....and I thought I had em on a couple of times rotatin the pots but wouldn't stay.

Sounds like you need to do the pot cleaning operation. May as well do all of them (both speakers) once you are in there.

I would bet your tweeter pot is at fault it is easy to fix just get it out of the speaker and then take it apart real easy. They get rusty from the heat and then then condensation from playing the speakers. Yes an open pot in this circuit would take out all the tweeters as it is in series with the main input for the tweeters all current flows thru this pot for the tweeter circuit.

Jerry
getting ready for the big operation(for me that is)....got the watkins out so i can look things over...can see considerable corrosion on the pots just looking in...Here is the question??? There is a black (capicitor maybe??) sitting right next to the junction block where the wires come down from above and just plug in. It is about 1/2 inch in diameter and maybe 3 inches long...Well anyhow it looks like it might have issues...a little bit of stuff comming out the end of it like its leaking maybe...should I,can I put in a new one,what does it do, and can I test it?
Thanks
Guy

Can you take a picture of it?
It sounds like it is a cap does it have any info you can read?
Where does each end go I can look at the scematics and see if I can tell what it is. Sometimes these are glued in so it just might be glue....

Here is the question??? There is a black (capicitor maybe??) sitting right next to the junction block where the wires come down from above and just plug in. It is about 1/2 inch in diameter and maybe 3 inches long...Well anyhow it looks like it might have issues...a little bit of stuff comming out the end of it like its leaking maybe...should I,can I put in a new one,what does it do, and can I test it?
Thanks
Guy
That sounds like the 40uF Callins NP electrolytic that serves duty as the high pass filter for the midbass coupler. You should replace it.

- JP

Or it could be the 13.6uf
here is a link with a diagram see if you can tell which one from this
http://www.infinity-classics.de/infinity/models/Quantum-series-1976/Quantum-Line-Source-QLS-1/QLS_1_crossover_schematics_01.jpg

Or it could be the 13.6uf
here is a link with a diagram see if you can tell which one from this
http://www.infinity-classics.de/infinity/models/Quantum-series-1976/Quantum-Line-Source-QLS-1/QLS_1_crossover_schematics_01.jpg
The larger Quantums used the tubular black and read Callins on the midbass coupler and the Watkins (earliest units) only. For the midrange and above, Infinity used yellow, rounded rectangular metalized polyethylene capacitors from Superior Electic (if I'm remembering that name correctly). Yet, your diagram shows otherwise though in my experience the layout of components in the larger Quantums changed several times. So, the only ways to be sure is to read the label on the cap, track back where the leads go, or check the wire color and check to see which driver that color is associated with (yellow for the midbass, iirc).

- JP

Charivari
I know you said this is a NP but would you consider putting in a metallized Polypropylene caps instead? You know Jantzen, Solen, Auricap, AudioCap, Kimber Kap Dayton ?

I know they cost more but would be better don't you think? Parts express has various films in a wide price ranges. Just looking for info as I have a few pair I am looking at recapping

Oh, the NP is just what's printed on the electrolytic Callins brand caps to indicate "non-polarized". The originals elsewhere were what are also known as 'mylar' caps, which were the better caps available at the time. I see no reason why better caps couldn't be used and in the case of film caps replacing the electrolytic caps, the level controls are there to make any needed adjustment should the levels change. When I recapped my Q2s much as I could afford at the time, I used polypropylene caps on the midrange with Wima MK4P bypass caps (same as used in the top B&W speakers) and Solens (which were what Infinity switched to in the '80s and are nearly the same price on Madisound as the lower quality Daytons on Parts Express) on the EMITs. The result was an improvement, but I also possess a bias for Solens (don't know where I got it from) so that may have influenced what I heard.

- JP

That sounds like the 40uF Callins NP electrolytic that serves duty as the high pass filter for the midbass coupler. You should replace it.

- JP
am at work now and it was hard to read what was stamped on it but the number 40 i could read for sure

Or it could be the 13.6uf
here is a link with a diagram see if you can tell which one from this
http://www.infinity-classics.de/infinity/models/Quantum-series-1976/Quantum-Line-Source-QLS-1/QLS_1_crossover_schematics_01.jpg
yep...its the third thing down on the right not counting the wiring junction...has the 40mf in the diagram...its not glue from being glued down, it looks like leaking from the end in two places....next question...where to get (radio shack??)and exactly what to ask for....can you tell not exactly my normal line of work....Thank You for your help!

yep...its the third thing down on the right not counting the wiring junction...has the 40mf in the diagram...its not glue from being glued down, it looks like leaking from the end in two places....next question...where to get (radio shack??)and exactly what to ask for....can you tell not exactly my normal line of work....Thank You for your help!

Depending on how much you want to spend I will give you options.
I would replace the 13.6uf also since you are doing this. Also the Tweeter caps
Parts Express has a wide varity and I will provide part numbers from them.
See links on bottom of page

Now you need to understand to match the values it is often necassary to wire caps in paralel

I speced the Dayton 1% there are cheaper ones at 10%

You need the following
for tweeter
Using Dayton 1%
2.5uf 1.0uf (027-210) $1.91 and 1.5uf (027-212) $2.12
1.75uf 1.5uf (027-212) $2.12 and .22uf (027-202) $1.35
1.25uf 1.0uf (027-210) $1.91 and .22uf (027-202) $1.35
Mid Range
13.6uf 2x 6.8uf (027-238) $4.71 each
Mid Bass Coupler
40uf 2x 20uf (027-252) $11.71 each

Using Solen this is harder not as many to use have to mix in Daytons or other
2.5uf 2.0uf (027-534) $2.69 Use a Dayton 1% .47uf (027-206) $1.43
1.75uf 1.5uf (027-528) $2.41 Use A Dayton 1% .22uf (027-201) $1.35
1.25uf 1.0uf (027-520) $2.05 Use a Dayton 1% .22uf (027-202) $1.35
Mid Range
13.6uf 2x 6.8uf (027-560) $4.37 each
Mid Bass Coupler
40uf 2x 20uf (027-582) $8.53 each

I also noticed there are a special bypass caps from Dayton that you could use where ever I called out a .22uf .47uf they sound good on paper :D
There are many other caps from other manufactures available that cost more but this should give you an idea.

goat..thanks for ur help.looks like the mid range 13.6uf and mid bass coupler 40 uf are just remove and replace

the tweeter caps are a bit confusing....how what you called out = what is in the diagram....looks like their is a 1.75mf, a 2.5mf, and two 2.5 mf in series:scratch2:

goat..thanks for ur help.looks like the mid range 13.6uf and mid bass coupler 40 uf are just remove and replace

the tweeter caps are a bit confusing....how what you called out = what is in the diagram....looks like their is a 1.75mf, a 2.5mf, and two 2.5 mf in series:scratch2:

The tweeter circuit has 3 caps only one is ever in the circuit at a time depending on what the switch is set to.

So the values are 2.5uf 1.75uf and 1.25uf

Look at the schematic here http://www.infinity-classics.de/infinity/technik/manuals/Quantum_Line_Source_1_technical_sheet.pdf

Make sense now?

printed off scematic..lookin at it now...yes 3 circuits only one at a time but don't see those values....(

wait....that is a diff schematic with diff values that the one above

so are the caps for the tweeters in the schematic on post #48 marked wrong or do I just not know how to read em?? seem to be diff from the diagram in post #56???

The shedule can be wrong. Had it with my Infinity's too... Pretty crappy if that happens by the way. My tip is: draw your own schematic and use those values...

so are the caps for the tweeters in the schematic on post #48 marked wrong or do I just not know how to read em?? seem to be diff from the diagram in post #56???
The schematics and information in the Infinity technical sheets are notoriously inaccurate, but in this particular instance such does not appear to be the case. The capacitor values in the crossover layout diagram are the same as in the schematic if you'll look to see how they're wired up. It would appear that Infinity was not always able to obtain capacitors of the type they desired in the values they wanted and so connected them in serial or parallel to obtain what they needed. (Capacitors behave in the opposite manner of resistors such that the values are added when connected in parallel or halved if two identical value caps are placed in series.) You'll see three caps in the schematic, four in the layout, but two of the 2.5uF capacitors are connected in series thus reducing their effective value to one half or 1.25uF as the schematic calls for.

Oh, for the 40uF capacitor, if you decide to go Solens, I recommend going to Madisound (http://www.madisound.com) as they have 40uF Solens along with some of the harder to find values PE doesn't have and they're cheaper than connecting two PE 20uF Solens in parallel. I've also had better service and quality of product through them than PE, but that's a different matter.

- JP

:ntwrthy: I see the light! :yes: Thank you for beating in into me

Here is the cap I used for the 40uf
It seems to work well in that spot. It is probably not as good as alot of other caps that you can buy but, then again it is probably better than the oridginal.

banffskiing

My relationship with my QLS-1's is getting better. After rediscovering vinyl a while back I have also made another profound discovery: you need a good turntable. I recently found a nice Bang and Olufsen Beogram 1700 turntable with an MMC 4000 cartridge (see photo). Wow. What a difference from my clunky old Pioneer TT. I can actually listen at decent levels without rumble and feedback. The QLS produces such low frequencies that TT's are very prone to feedback issues. But the B & O takes tremendous volume and low frequency music to feedback. The 1700 is not the best B & O, but it is light years beyond the old Pioneer and the old Marantz TT I'm trying to resuscitate. They will have to be relegated to my "secondary systems".:thumbsdn: But the QLS's are holding up very well.:thmbsp:

The journey continues......:thmbsp:

update and a story....ordered the dayton caps goat recommended and the 40uf that banff used.so far only installed the leaky 40, cleand the pots and have new to me amp and preamp....have had them for 3 decades..tons better..stayed up several nights almost all night long,listening and wonderin why I never fixed em before..

now for the story..Had to go to Fla last weekend for a funeral(I live in NY). Found a pair of Q 2 while their, just listed for $250, about 2 hrs away. Didn't sound all that good but took em anyway. Now what to do with em.

cabinets, a few scars but all and all not to bad
watkins woofers present and ok
emits all work
domes...2ok.. one broken wire...one replaced with aftermarket
midbase couplers work but looks like little fingers pushed in the middle a bit

now the bigger problem...the crossovers..not a wire on any of the pots..even chopped off the terminals on some of em....think their should be 2 ceramic resistors...their gone...who knows what else

anybody have exta crossovers for Q 2? Advice? Worth fixin? They look like they would be good company for their big brothers