Infinity Quantum 4 Questions

[tubed]

I agree Ken about the original Watkins supplied woofers having both small and large magnet structures.
I don't know why Watkins would be blowing smoke up the OP's arse. I can't believe he'd just be trying to sell a new pair...unless more than likely the OP was thoroughly mistaken on all counts

 

[jt45]

I also agree with Ken and would follow his advice on the mids, I repaired mine without any guidelines other than a post by tubed about using stripeeze to get the old glue off. However it worked out good and I didnt have to take them apart. It was a tedious job and my eyes needed alot of help.

I also thought it was odd that the OP would be told the paper cones were later models as it seems more like the opposite.

Your right Ken I doubt those Q4s will get down near 18hz I was just stating specs and hoping the OP would see they are more than capable of doing the job and he should be glad he has a set of original woofers.

Re-foam them and enjoy !

 

[Yamahalic]

My guess is that the Quantum era 12" woofers started out with paper cones, switched to poly cones, then later only the lower models (Quantum-4 and lower) were switched to lower cost drivers with paper cones. This theory combines what has been stated in this thread, and also includes what Bill Watkins told me.

 

[Ken Boyd]

I would also add that I beleive that many of the later poly cones were not supplied by Watkins but were supplied by a Japanese supplyer. As per a conversation I had with Mr. Waktins that those later poly cone speakers with the larger silver magnet were not supplied by Waktins. I am not sure of this fact but I did go to his website and veiwed the pics of his replacement drivers and they appeared to be the same as the older stamped metal model with the smaller magnet than the poly cone version with the magnet the same size as the basket. And as far as part numbers the old versions have the same part number on them as the new versions. In fact just last year I was able to order some brand new dome mids directly from Harman kardon and I order the mids using the part number from their tech specs, and what I got was a newer version of the old mid but it had that same part number on it. Gone was the small tinsle wire on the front, it has a silk dome instead of the old black dope diaphram, and the front bezel is textured rather than smooth, it drops right in just as a factory OEM model mid.

 

[tubed]

My guess is that the Quantum era 12" woofers started out with paper cones, switched to poly cones, then later only the lower models (Quantum-4 and lower) were switched to lower cost drivers with paper cones. This theory combines what has been stated in this thread, and also includes what Bill Watkins told me.

Sorry, you seem to be far off the mark.
The Quantum 4 was an early 1977 Quantum model speaker that came equipped with the early and original Watkins "paper" cone. There was no switch to poly.
Poly-coned "Watkins" woofers had to be outsourced to a Japanese supplier around 1980(give or take a year) when Watkins quit making the driver for Infinity...my theory is BW was refering to those drivers as being the "cheaper" ones, the ones he didnt produce.
I believe the smaller magnet, 1 1/2" voice coil Watkins drivers were made and voiced specifically for the smaller cabinets and driver configuration of the Q4 and Q5....IMHO

 

[goat67]

Sorry, you seem to be far off the mark.
The Quantum 4 was an early 1977 Quantum model speaker that came equipped with the early and original Watkins "paper" cone. There was no switch to poly.
Poly-coned "Watkins" woofers had to be outsourced to a Japanese supplier around 1980(give or take a year) when Watkins quit making the driver for Infinity...my theory is BW was refering to those drivers as being the "cheaper" ones, the ones he didnt produce.
I believe the smaller magnet, 1 1/2" voice coil Watkins drivers were made and voiced specifically for the smaller cabinets and driver configuration of the Q4 and Q5....IMHO

On the Q5 s I have the paper large magnet drivers so there goes that idea.
Bought new in 1980

 

[Ken Boyd]

On the Q5 s I have the paper large magnet drivers so there goes that idea.
Bought new in 1980

So your magnets on the back are the same size as the basket and it has paper cones? I have never seen a set like that.

 

[tubed]

Here's a pic of a couple of early Watkins woofers.
The one on the left from a Q2 , the other from a Q4....neither are marked with the Infinity 902-1180 code.
The driver on my QLS-1s are polys with an even larger magnet than the one pulled from a Q2 and marked 902-1180.

 

[goat67]

So your magnets on the back are the same size as the basket and it has paper cones? I have never seen a set like that.

Well I know when I sent them to Bill Watkins he said they had the larger magnets he spoke of two different types but I would have to pull one to verify.

 

[Yamahalic]

Here's a pic of a couple of early Watkins woofers.
The one on the left from a Q2 , the other from a Q4....neither are marked with the Infinity 902-1180 code.
The driver on my QLS-1s are polys with an even larger magnet than the one pulled from a Q2 and marked 902-1180.

Interesting that my Q4 drivers look similar to yours, but are definitely different in the area just under the magnets. I am beginning to think that Infinity simply made changes to the Quantum series 12" drivers as needed (i.e., not necessarily tied to any model year design changes). Perhaps they had to switch suppliers throughout the years for various reasons, so the basic design philosophy (dual voice coil, OHM rating, mounting points, etc.) was retained, but they felt that exact physical/visual continuity was not a priority.

So, my take away from this is that I am thinking that performance variations between the various 12" drivers may be less than I was led to believe. Thank you all for the feedback, I think I will refoam my drivers and restore my Q4s as original as possible.

 

[jt45]

Here is a pic of the Watkins Paper cone woofer from my QLS1
Serial numbers 7002282 and 7002283 These were purchased new by a friend
of mine late 70s and never worked on till I got them. In fact he stops by now and then
to have a listen, although he needs hearing aids these days to do so.

 

[tubed]

Interesting that my Q4 drivers look similar to yours, but are definitely different in the area just under the magnets. I am beginning to think that Infinity simply made changes to the Quantum series 12" drivers as needed (i.e., not necessarily tied to any model year design changes). Perhaps they had to switch suppliers throughout the years for various reasons, so the basic design philosophy (dual voice coil, OHM rating, mounting points, etc.) was retained, but they felt that exact physical/visual continuity was not a priority.

So, my take away from this is that I am thinking that performance variations between the various 12" drivers may be less than I was led to believe. Thank you all for the feedback, I think I will refoam my drivers and restore my Q4s as original as possible.

Sorry for being a little abrupt, Yamahalic:yes:
However I was was very interested in figuring in my mind the different variations of the Watkins woofer( the subject has come up more than once on AK)
Plus I really didnt want you to feel you had a "cheap" version for your Q4...once refoamed and driven with a nice amp I believe you'll be quite pleased with the Q4, especially its bass response!

 

[tubed]

Here is a pic of the Watkins Paper cone woofer from my QLS1
Serial numbers 7002282 and 7002283 These were purchased new by a friend
of mine late 70s and never worked on till I got them. In fact he stops by now and then
to have a listen, although he needs hearing aids these days to do so.

Yes. The woofer from my QLS-1s has the same big old honkin' magnet:yes:
However, with a clear poly cone I believe were produced in Japan, marked with proper replacement code number.

 

[jt45]

In fact just last year I was able to order some brand new dome mids directly from Harman kardon and I order the mids using the part number from their tech specs, and what I got was a newer version of the old mid but it had that same part number on it. Gone was the small tinsle wire on the front, it has a silk dome instead of the old black dope diaphram, and the front bezel is textured rather than smooth, it drops right in just as a factory OEM model mid.

Ken are those still available ? And did you have to make any other changes or just hook them up and go ? Im wondering what the cost would be to replace my mids with those. Auction prices on the originals are pretty high and you never know what your getting, they dont ship well either for the casual seller who doesnt care.

 

[Yamahalic]

...I was was very interested in figuring in my mind the different variations of the Watkins woofer( the subject has come up more than once on AK)...

This topic has become of interest to me lately. This thread alone has shown a great many variety of 12" drivers that were used in Quantum units. I looked through a few Quantum tech manuals from Infinity, and ALL I have seen (QLS-1/3/4/5) list the 12" drivers as the "902-1180 (Substitute NONE)". This could mean that these Quantum speakers at some point came with the marked 902 drivers. OR, it means that Infinity loosely applied this part number to many variations of this driver. The variations may have been purposefully applied to selected units, or as supersessions of past drivers no longer available.

Attached is a side-by-side look at my own and Tubed's 12" QLS-4 woofers. Also, an image group of all the 12" Infinity Watkins type DVC 12" woofer images I have come across recently.

 

[tubed]

Good work Yamahalic.
Just remember there was a period in time when B. Watkins was not producing drivers for Infinity and his beautiful new woofers might not be labeled with the Infinity replacement number...I had a conversation with Watkins via telephone, and he admitted all versions of his woofer should function well in different Infinity models.

 

[Ken Boyd]

Getting replacement drivers is hit or miss depending on who you get on the phone per day. One day they say they are out then another day they say the computer has them. One day the lady said they had 77 diaphrams for the QLS-1 in stock, I called back the next day and she said they only had three, I ordered all three and they showed up in about a week. Same thing with the mids, they don't say they are NLA just they are out of stock, the ones I got costed me 137 dollars each and they were brand new, exact fit only they look slightly different as I said in a prior post. Somewhere in on one of the threads I posted picks of the new mids I received. Same size driver, same size diaphram, just its a silk dome, and their is no exposed tinsle wires. I ended up using them in a pair of my QLS-2s and took out the working mids of the QLS 2 and replaced a few in my QLS 1's that I was unable to repair. I didn't want to have a mismatch of drivers in any of the speakers. Not sure if I would have been able to hear the difference but you could see the difference. The EMIT's were the same as the old ones only I just ordered diaphrams and they said they didn't have any complete drivers. When you call the HK parts department its like you talking to some girls in Hong Kong, always Asian girls, that don't know anything other than taking your part number and inputing in a PC.

 

[jt45]

Wow pricey devils arent they, I like the Idea of no tinsel wires to deal with but it would cost two arms and a leg to replace all the mids on the QLS1s, not to mention (the phone call). Thanks Ken.

 

[jimreeves]

You should have a look at the sticky threads at the top of this forum. The Watkins White Paper thread covered this subject before.

Don't be put off by the magnet size, it should vary according to the cabinet volume it was designed for (if the designer cared about total system Q). It's explained by Mr. Watkins himself in the White Paper.

 

[tubed]

Don't be put off by the magnet size, it should vary according to the cabinet volume it was designed for (if the designer cared about total system Q). It's explained by Mr. Watkins himself in the White Paper.[/QUOTE]

Thanks JR.
Can't agree more.