A Piece of History - the Infinity QLS-1

waudio

Active Member
When I first became interested in the vintage Infinity speakers toward the end of 2010 - I came through a listing in ebay about a pair of dusty, boxy, and generally ungainly looking speakers that had been recently discovered after about 20 years in storage. Without knowing much about them - I put a bid and continued with the bidding until I decided to stop at around $600 - as I was not sure how much worth they are. That pair was sold for $800 and I believed they went to Dr. Marks.

Since then, I learned that they are the much sought after Infinity QLS-1 - the venerable patriarch of the Infinity lines. Interestingly, my 2nd encounter with the QLS-1 was also through ebay - hours only after I had purchased my RS-1b. It was going for a very reasonable price and I put a top bid on it. Alas - the bid ended when I was on a Southwest 737 going over Iowa - on the way to Seattle for business trip and to pickup the RS-1b. I was outbid by $100. Thus, it took me a huge restrain not to call the seller when I saw another pair for sale in Texas (Austin, I believe) not too long ago. My most precious wife is very understanding but I don't want to over extend her welcome. This pair went to tomlinmgt.

Patience is a virtue - that rings very true. Having accomplished significant house improvement work - I got some courage to look again. Lo and behold - one pair came up not too far away - and in mint condition. It came with the original box and packaging and 2 pairs of spare Watkins woofers. All woofers need new foam surround. All at a price that is a little more than 1/2 of what I paid for my RS-1b (including shipping). The brochures and original receipts are there too.

Took a day off today - and picked them up at the Boston shipping dock. I am so excited - but I need to wait for my friend to come and unload them from the truck.

This pair will go to the 2nd floor where my RS-2b's used to sit. More pics later until I get a chance in the next week or so to unpack and set them up.
 

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Well now Micheal can add you to his list of QLS-1 owners! We will be interested in hearing your reviews of them compared to the RS-1b's.
 
Great post as always waudio. Glad you found a pair and wow boxes, there can't be many of those around anymore.
Jim
 
And yet another hawk that was circling the QLS-1's down in Austin comes forward! Man, I'm glad I made a move because had I waited another weekend I feel pretty strongly they would have been GONE.

Congratulations, man. Sounds like you got a very nice set. I'm excited for you and anxious to hear all about the relationship that's fixing to develop. :yes:

Tell us about your room and upstream gear.

- Michael
 
Thank you all - kenboyd, slimpikkins, goodolpg, tomlinmgt - for the support.

With the help of a friend yesterday - we managed to get them off the truck and into the house. My back was a little sore afterward - as we had to climb quite a few stair steps.

It will take sometime for me to get this setup. I do have spare Watkins already that I can use right away - but I think that I should bring them to my primary listening room first (in the basement where the RS-1b's are) - and do a shoot out - using the same amps and the same room.

tomlinmgt - I am using carver tfm-45/42 amps, with DAC-09, and Denon 1560 CDP. No preamp yet. I just recently purchased a First Sound Preamp (Presence Deluxe MK2 with factory mods on the attenuators). It will be here in few weeks. I also have purchased a pair of VTL-300 monoblocks with tungsol 6550 newly manufactured tubes. I am a fan of the TFM-45/42 - and I am hopeful that the VTL will be better but I am not very optimistic that it will be a whole lot better - especially that I am only listening at moderate volume.

@tomlinmgt, I have been following your postings on the "Listening Spaces" forum - and have taken a few pointers from you (and revmen) to improve my listening room (front-wall). I have posted what I am doing in a separate thread in this infinity forum. It would be helpful if you can give some pointer & critique as to what I am doing right and what I am doing wrong on the room treatment.

I included some pics here that I got from the seller. I will post more pics in a few weeks after I get a chance to unpack and setup downstairs.
 

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Wow Waudio, :banana:

Those QLS-1's look pristine! Very clean. Some of the best QLS-1 pictures that I've seen. Even the mid-domes look nice and shiny, with no signs of dome warp-age (from being over driven?). I also like the clear poly Watkins woofers. They look like the woofers used in IRS-III's? I wonder if they're the same driver? :yes: :no:

Also, how do you like your DAC-09? I have one, but it's mainly being used as a PC DAC, headphone amp. I wonder how it would sound in my stereo set-up? I could even bi-amp my Monsoon's, with the tube output on the planar mids/ tweeter section, while using the SS output for the woofers... Just a thought... :scratch2:

Congratulations!
 
Nice score waudio! Wish mine looked like that when I got them! If this pair has been in storage, expect to need to clean the pots for the emits, mids and midbass. It's much easier to do when the woofers are pulled for refoaming. Also check the condition of the caps and resistors while you're in there.
Here's the link to the tips and tricks I've compiled so far, thanks to AK members!
http://www.audiokarma.org/forums/showthread.php?t=386845
 
Jim's a prince of a man for compiling that data base for us. It was an invaluable reference for me while researching and restoring my Q1's. So, once again, thanks Jim.

waudio,

When I saw your serial numbers were low I wondered if you'd have the black or walnut baffle. And for some reason I was thinking the black baffle Q1's had the dark gray/coated cone Watkins drivers rather than opaque poly. Like has been pointed out before, with Infinity you just couldn't be quite sure what they'd pull off the shelf from one run to the next. Keeps things interesting, I suppose.

I'd be glad to offer whatever sliver of wisdom I have wrt room acoustics and treatments. I'm far from an expert...and my practical knowledge is limited to what I've done in my listening space and my friend's. Both were acoustically challenging and now sound several orders of magnitude better, but if you need to get really technical then Revmen is your guy. I got a lot of guidance from Josh and everything he suggested made a difference for the better. Really, I think the key is not having to worry about disrupting decor. If you have a dedicated space it's quite simple to find the right blend of absorption and diffusion....especially if you have a clean slate to work upon (no decor). I think my Q1's (and my MG-IIIa's) work (still sound "big") in my smallish room (14x20x8) thanks in no small part to the acoustic treatments I've implemented. I'll have a look at your other thread, for sure.

- Michael
 
Also, how do you like your DAC-09? I have one, but it's mainly being used as a PC DAC, headphone amp. I wonder how it would sound in my stereo set-up? I could even bi-amp my Monsoon's, with the tube output on the planar mids/ tweeter section, while using the SS output for the woofers... Just a thought... :scratch2:

Congratulations!

I'm using a DAC-09 and absolutely love it in my 2-channel rig. My friend let me borrow his PS Audio DAC (around $1K) and it didn't take me much time at all to determine I preferred my GF DAC. I went ahead and kept his PS Audio DAC in my rig for a few weeks and I grew used to it's character but once I put the GF DAC back in my rig I was much more pleased with its performance. I haven't yet rolled the tube in it.

- Michael
 
Thanks stimpywan, jimreeves, tomlinmgt, and others. I will surely look into the links and make effort to clean the pots.

@stimpywan: I like the DAC-09 - but not with the original tube. I am using the GE 5 White Star - which is similar to the GE 5 Red Star. I found it to be the best for me so far.

@stimpywan & tomlinmgt: I have a pair of the GE 5 Red Star - if either of you want it, I can give you one of them. The White Star seems to be a little brighter than the Red Star - I like both of them. Send me a PM if you want it (no cost).


@tomlinmgt: The first picture from the seller shows the original woofers. I think they were the black paper cones. The clear poly woofers that are currently on them - are clearly replacements - as the seller also informed me.
 
Yeah I think the clear ones, Watkins, were most often used in later models, and yours having the black front baffle is an early model of the QLS-1. But some of the later QLS-1's which have the walnut front baffle also had the gray pulp type of Watkins, mine came with them, but I have since changed them out to a pair of Poly cone drivers.

And as Jim posted those Lpads in the back are almost always a problem, along with midrange tinsels and as Micheal can tell you, EMIT's that don't work, often in pairs as the solder joints seem to get very hi in resistance and sometimes just stop working. And they are wired in a way that usually when one stops working the one right next to it stops as well, depending on which one the pair stops working.
 
Yeah I think the clear ones, Watkins, were most often used in later models, and yours having the black front baffle is an early model of the QLS-1. But some of the later QLS-1's which have the walnut front baffle also had the gray pulp type of Watkins, mine came with them, but I have since changed them out to a pair of Poly cone drivers.

And as Jim posted those Lpads in the back are almost always a problem, along with midrange tinsels and as Micheal can tell you, EMIT's that don't work, often in pairs as the solder joints seem to get very hi in resistance and sometimes just stop working. And they are wired in a way that usually when one stops working the one right next to it stops as well, depending on which one the pair stops working.


Yes, just as Ken said on the L-pads and EMITs. All my pots were corroded and when I did the recap I just tore 'em down and soaked them in CLR. Seem to work fine now, though I don't ever touch them. Testing the EMIT drivers individually while still mounted in the cabinet can be tricky with the line source design. They're so close together it's hard to discern if the one you're trying to listen to is working or if it's the one above it or below it. What you need to do if you want to isolate each driver without removing it from the cabinet (you may already know this technique) to isolate the EMITs (and dome mids) and you can do this by getting yourself a cardboard tube from a roll of gift wrapping paper. Some folks like to use the tube from a roll of paper towels but it's too short for this method with the line source configuration. Simply take the tube and put one end up to an ear and the other end right up against the face the driver (in the case of the dome mids, right in front of). Then move the tube away from the driver horizontally so the end of the tube is positioned over the baffle. This will give you a "driver on/driver off" effect. If you hear no difference between when the tube is over the baffle or over the driver you know the driver is dead. This technique is also good for testing the output strength of the driver. If you have very weak ones, you most certainly have high resistance in the solder joints. I'd be very, very surprised if you don't have any EMITs suffering from this. I reflowed all the solder joints in mine and after the repair got the resistance values down below seven ohms, I think, with most in the five ohm range. Some do sound louder than others, but IIRC the wiring was such that some of the EMITs were out of phase with others and this may be the reason for this. I meant to go back and double check it but didn't. That being the case (a few weak EMITs), I have never wanted for more HF presence since the repair. It sounds just fine. :yes:

And thank you very, very much for the offer on the tube. I will most certainly take you up on that! So PM is coming!

And I just got a call from my tech to let me know my tube pre is ready to pick up. I'm very excited to get to hear the Q1's with the tube pre. For the brief period I got to hear the two together it was sensational.

- Michael
 
Also might be a stupid suggestion but check your bass drivers wiring, I have seen quite a few post where the bass drivers leads were not correctly wired to the right terminals. Some one probably had them refoamed at some time and possibly the person refoaming them didn't know anything about dual voice coils, so make sure the right wires are connected to the Watkins as it two sets of terminals one for the 4 ohm VC and one for the 2 ohm VC, you have to connect the correct wires for the Watkins to work correctly.
 
Also might be a stupid suggestion but check your bass drivers wiring, I have seen quite a few post where the bass drivers leads were not correctly wired to the right terminals. Some one probably had them refoamed at some time and possibly the person refoaming them didn't know anything about dual voice coils, so make sure the right wires are connected to the Watkins as it two sets of terminals one for the 4 ohm VC and one for the 2 ohm VC, you have to connect the correct wires for the Watkins to work correctly.

True...my Q1's being the most recent example of that. Before I figured out what was going on it put a big 'ol Emotiva XPA-2 into protection twice. But my Soundcraftsmen MA-5002 never skipped a beat. :thmbsp:


- Michael
 
Also might be a stupid suggestion but check your bass drivers wiring, I have seen quite a few post where the bass drivers leads were not correctly wired to the right terminals. Some one probably had them refoamed at some time and possibly the person refoaming them didn't know anything about dual voice coils, so make sure the right wires are connected to the Watkins as it two sets of terminals one for the 4 ohm VC and one for the 2 ohm VC, you have to connect the correct wires for the Watkins to work correctly.

I've read several of those threads. The problem I believe lies with which coil is number one and which is number two. The schematic does not tell which is 2 ohm and which is 4 ohm only number one and number two and if you are like me you can't tell by looking at the rest of it to figure it out.

Does anyone remember which is which on the schematic? Then one could just use their meter and label them.
Jim
 
Congrats on getting those waudio.
Good info you guys as I have 2 Emits that aren't working on my pair right now. They are the 2 bottom Emits on 1 of the speakers and after reading this I will have to check and probably reflow the solder.
Congrats again on picking up a beautiful pair of speakers
 
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I've read several of those threads. The problem I believe lies with which coil is number one and which is number two. The schematic does not tell which is 2 ohm and which is 4 ohm only number one and number two and if you are like me you can't tell by looking at the rest of it to figure it out.

Does anyone remember which is which on the schematic? Then one could just use their meter and label them.
Jim

The voice coil with the lower impedance is v.c. 2.

The + wire going to v.c. 2 is black and is wired directly to one side of the 1400mF cap as you move upstream the signal path.

Either of the red w/black stripe wires can be used as - leads to either v.c. 1 or 2.

- Michael
 
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