I got a good story. A local Ak'er saw I had 2 pair of SM-255s and e-mails me asking if I still have them and do I want to sell. OK sure I sell one the MINT pair for $325 Sunday. I was a little gloomy about selling them so I go out to CL Monday night and see a pair of Quantum 3s for sale for $225. Ok so I fire off an e-mail and before I know it I've got a pair of Q-3s in excellent condition minus the foam on the woofers of course. One of the speaker covers is missing the wood frame and the infinity logo but hey it still connects and you cant tell from looking at them that the underside frame bit the dust. One minor rip in the other screen. I'm going to be bi-amping with a pair of Technics SE-9060's, probably horizontal bi-amp and see if there's enough head room in the 9060s for these. More to come once I get the woofers out and see what I need to do to get these back in working as new condition. Does anyone here have any suggestions on where to start??

Here's a few pics from the cl ad and I will take more when I start working on them this weekend.

Did I make a good trade up??

Cheers,
Bob Brown

sounds good to me! i remember seeing that pic with the red wire dangling on CL a while ago :) a few tips i've gleaned about the Quantum series:

did you check to make sure the exposed midrange wires are intact? sometimes the break can be hard to see at first glance and it might just look like the brownish resin is cracked, but you don't want to wiggle it TOO much to find out for sure - it will break on you very easily if it's not broken already.

if you pull the woofers at any point, make sure to mark which wire goes to which post. because they're dual voice coils, it may be tricky to get the proper phasing by ear. i don't think they're too hard to refoam if you want to try it yourself, but i gave mine to a pro because i wanted them to look as close to new as possible, and because one of the voice coil gaps was very small.

the other thing you'll probably want to do is use De-oxit on the tweeter and midrange pots. if they feel sort of rusty and don't turn very easily, it will mostly likely affect the sound. shoot them from the back and then shoot them from the inside as well (after you've taken the woofers out and exposed the crossover). some have had to take the entire pot apart, but that might not be necessary for you.

Personally, I think you made a major upgrade. You should really like them.

One thing I would recommend: when you have the woofers pulled (and have labeled all the wires like cdfac suggests), give the crossovers (at least) a visual inspection. On my Q2s, there were loose/disconnected wires, including some that had never been soldered in place originally, obviously the wires were just pushed through the solder tabs. Appalling quality control on the crossover assembly. Getting everything hooked up properly makes an amazing improvement in the sound!

Congrats, that was a nice trade up you made there.

David

Great score Bob. Where they the ones in the Philadelphia area? If they are I'm glad someone from AK got them. They were relisted a couple times, I was tempted when they were at 250 but I got too many house projects. Be sure to let us know how you make out.

Great score Bob. Where they the ones in the Philadelphia area? If they are I'm glad someone from AK got them. They were relisted a couple times, I was tempted when they were at 250 but I got too many house projects. Be sure to let us know how you make out.

Yes they are - original owner WAF said they had to go. The owner Bob said "tell her how good they sound" - I said you should take him out to dinner with some of the $$ from the speakers. They had a very nice redone house too with a VERY large listening/living room that those speakers would have sounded great in as well. The owner knew absolutely nothing about repair or even what was wrong with them. The enclosures are mint and in VERY good condition - not a scratch on them. Hard to believe. I told him $250 for untested was a fair price. I just got a price to have the woofers re-aligned re-foamed from Watkins at $128 including shipping and also a price from local to me (no shipping) same service from Millersound whom did my woofers in Dahlquist DQ-12s for $70. What would you do? So tried and true local service, or from the original manufacturer??

Ok movin on... Upon closer inspection the midbass driver foam in one is in need of replacement as well. So both of them would need re-foamed. Another question now. The Dome Midrage driver foam looks to have tiny pinholes in the foam and the foam cover feels a little tacky and about to disintegrate. Does that foam need to be replaced as well or is it just a protective cover?

Also what tweeter is in the rear? I can't really see it and don't know how to get at it either. I know it's there tho.
Looks like these speakers are going to need a complete service top to bottom. The boxes are well taken care of but all the drivers are suffering from neglect. I suspect these have been sitting in storage for some time.

I want to do them right and bring them back to former glory so these will be keepers. Told the WAF - see it's going to be your retirement investment. When my hands are cold and I'm dead and gone you can sell off my gear and these speakers are going to be part of that.

So I have 4 pair that will be for sale when I'm gone!! (so far).

Also the original owner said the wood was TEAK?? Looks like walnut to me. Did they come in teakwood veneer or only in walnut? I think these look alot better than the usual OAK from the larger siblings from Infinity but hey thats prolly cause I haven't listened to the older larger brothers. These definitely passed the WAF - she didn't even bat or blink when she first saw them and I got the go ahead nod to purchase. So I gotta say my girl is AWESOME and has been my best friend with regard to my vintage audio quest. We picked up those speakers after work on HER birthday ta boot. How bout that, and she's still loving me.

So here's a big ol bottoms up to my girl Anna. She is absolutely the best.

I used to fight with my ex-wife just to purchase a CD. Of course when we separated she took half of the CD/lp collection AND my stereo system. All good now, actually made room for far better gear!!

Cheers,

Bob Brown:beer:

The enclosures are mint and in VERY good condition - not a scratch on them. Hard to believe. I told him $250 for untested was a fair price. I just got a price to have the woofers re-aligned re-foamed from Watkins at $128 including shipping and also a price from local to me (no shipping) same service from Millersound whom did my woofers in Dahlquist DQ-12s for $70. What would you do? So tried and true local service, or from the original manufacturer??
......
Ok movin on... Upon closer inspection the midbass driver foam in one is in need of replacement as well. So both of them would need re-foamed. Another question now. The Dome Midrage driver foam looks to have tiny pinholes in the foam and the foam cover feels a little tacky and about to disintegrate. Does that foam need to be replaced as well or is it just a protective cover?
.......
Also what tweeter is in the rear? I can't really see it and don't know how to get at it either. I know it's there tho.


It's great that the cabs are so nice. Definitely helps out the WAF!

You will hear varying opinions about refoaming shops. It's a fact that pretty much everyone is happy with Watkins Stereo's work. But these woofers aren't much more difficult to refoam than most 12"s, from what I've gathered, so if you were happy with the performance and appearance of Millersounds' work before, why not try them again?

The midbass couplers shouldn't have any foam, as they all had rubber surrounds from the factory AFAIK. If there is foam, that would mean there was a repair job and either the rubber was replaced or a new driver was installed.

The dome midranges can look shabby sometimes, but they are made of treated cloth which should still sound good (what you see IS the speaker, there isn't anything covered). The holes are supposed to be there and it should feel soft and flexible. If they are really in bad shape, you may be able to find one for a decent price on eBay, or perhaps an AK member may be willing to part with one.

The tweeter on the back is a half-line source EMIT, which uses the same technology as the front tweeters but is shaped differently. Also, you may find as I did on my QLS1's that it doesn't seem to work, but in my case it was the wiring or pots going bad, causing it to go in and out.

You really have some nice speakers there and a great girl to share it all with, congrats!

Chris

Chris you are correct the mid-bass surrounds are rubber and one has a tear in it where it overlaps the frame. Can these be repaired like re-foaming cept with rubber?

Bob

could you post a pic? i have extra one that has a tear in the middle and where the rubber meets the frame. i was thinking about trying to glue it from beneath, just to see how it worked. if you only have a tear by the frame, depending on how big it is, glueing might be worth a shot. i can let you know how mine turns out. the nice thing is that it isn't a sealed setup, it's a transmission line or line-loaded setup (i think that's what you call it when it's mounted in a tube and vented out the back like that) - a small tear in that place may not matter at all when it's all said and done. i'm sure you can find some way to replace the surround with either rubber or foam, but i wouldn't do that unless you have to. might end up about as expensive to just find a new one on eBay - for example, i got a pair for ~$50.

Here's a few pics - the one with my hand in the pic is supposed to show where the tear in the rubber gasket is. The other one is fine. The pic from the top shows the only cosmetic flaw and that I did carrying them into the house. It's a hair line splinter in the veneer. A little wood glue and it will be good to go. Watkins woofers out and on the ground. I took a look at the crossovers. They look pretty impressive. Also the pots on the back of the crossover feel scratchy at best. They feel pretty cheap in comparison to the rest of the build quality on these. I saw a thread on how to R&R those pots - I'm guessing I have to pull the crossover to get at em. Anything to watch out for when removing the crossovers other than minding where all the wires go?


Cheers,

Bob

They look in reasonable condition for their age.

Why not go the next step and take all of the drivers out and get the cabinets polished up, new cables and check the crossover for dried up caps and high value resistors and dirty pots ;)

This is what they look like new. A little bit of elbow grease would bring them up.

http://www.infinity-forum.de/quantum_3.html

http://www.infinity-forum.de/Images/Quantum_3_01.jpg

"Why not go the next step and take all of the drivers out and get the cabinets polished up, new cables and check the crossover for dried up caps and high value resistors and dirty pots"


Anyone here have suggestions on how to bring the finish on these speakers back to glory. I'm thinking of doing this while the woofers are re-foamed. Might as well... Also I need to fix the tear in the mid-bass driver as well. I might get the folks that are going to re-foam the woofers do the mid-bass. So while I'm in there I might as well take these puppies apart and clean up the cabs. All they look to need is some oil. The wood is in good condition with no scratches etc. Is there an oil or some liquid something or other that anyone can recommend? I don't want to sand down the cabs as there really isn't any need for that drastic a step. I think rejuvenating the original finish is best in this case. Any suggestions??

TIA,

Bob

I asked the same question on another thread and most people recommended Howard's wax and polish ;)

http://www.audiokarma.org/forums/showthread.php?t=170177

that midbass definitely needs a new surround.

EDIT: i just superglued the small tears in my midbass' surround. i have some hope that it will hold up to power. i'll test it out later tonight. if it passes, you're welcome to have it, Bob.

Very nice score. I live in the city in which they were made and can't remember ever seeing a QLS available in my area. I guess everybody who owned them moved away, either that or there are quite a few collecting dust in triple digit temperature garages. BTW, I thought those mid bass couplers would be in sealed tubes, keeping them from acting like little passive radiators and protecting them from low frequency pressure. Enjoy!

he Mid-bass coupler does reside inside a tube. The tube extends inside the box all the way to the vent in the rear of the box. Now I'm wondering where the rear tweeter is. I thought it was where that vent is and it was inside. Anyone have clue where the 3rd tweeter is? According to the specs theres a 3rd "rear" tweeter!??

prob like a pair of Q2's that i have....no rear tweeter....apparently some made without along the way

he Mid-bass coupler does reside inside a tube. The tube extends inside the box all the way to the vent in the rear of the box. Now I'm wondering where the rear tweeter is. I thought it was where that vent is and it was inside. Anyone have clue where the 3rd tweeter is? According to the specs theres a 3rd "rear" tweeter!??

According to the specs there is no rear tweeter on this model. That only came out with the Q2 and QLS. However did you know these things have a 3db cutoff frequency of 28Hz which means some serious bottom end with the right amplifier :music:

Introduced: 1977

Dimensions: 102 x 45 x 33 cm

Bass: 1 x 30 cm

Mids: 1 x 10 cm midbass coupler, 1 x 3,8 cm

Highs: 2 x EMIT

Suggested for amplifiers with: 60-250 Watts per channel

Frequency range: 28 Hz - 32 kHz

Crossover frequencies: 200 Hz, 600 Hz, 4000 Hz

Suggested price (pair): 1050 $

i think the confusion about the rear tweeter may have started with the opening for the end of the midbass tube. it's about the same size and is covered with the same material as the rear EMITs are.

also, there are some quantum speakers with the same midbass that doesn't vent out the back and is instead mounted in a closed cylinder. i'm guessing the effect is supposed to be the about the same.

I see your spec sheet and have one in hand that states everything you mentioned with one exception. The Technical Manual I printed from Infinity for this speaker has

"TWEETER (Rear) #902-0157 Diaphragm NLA"

So there may be more than one version? Interesting...

Aw well my pair doesn't have the 3rd one.... Woofers are out and ready to head off to the shop tomorrow. Hopefully when they are done I will be able to take a listen and see if there's anything else amiss. I may test the tweeters with a DVM to see if there's anything needed there as well.

The dome midrange diaphragms seem good to go, no broken tinsel or anything like that.

Cheers,

Bob