Wharfedale Super 3 Tweeter Restoration

[angelaudio]

I’m restoring a Wharfedale 3-way system and the Super 3’s are next up in line for restoration. I was able to restore a pair of W15FS’s to working condition with the help of @klipschorn and now I’m documenting the restoration of the super 3’s.

I have a pair of the Super 3’s but they are slightly different. Here’s the first one:

And here’s the second one:

The first one says 14,500 lines and has a longer speech coil while the second says 13,000 and has a shorter voice coil. They were both made in 1958 but the first one was made in December and the second in June. They both read just above 9ohms. Do you think these will sound alike once restored? Will the one with less lines and a shorter voice coil roll off quicker than the 14,500 lines one?

Robert, I will once again require your expertise to guide me through the refoaming (or reFelting) of these drivers. I did see your page about the super 3’s but I have more than a few questions regarding the work you put into getting them functioning again. Primarily, what is the thickness of the felt you used and What thickness was the foam you used to cute the new spider from?

-Ernie

 

[klipschorn]

Since these materials are easily compressible, they are difficult to measure with a micrometer. Both these measurements are noted at the point of friction when pulling the material from the micrometer, using the foam as a reference for that friction as the foam is sold as 1/8" (0.125")

Using a caliper micrometer, the foam measures 0.124" (3.15mm) in thickness. The felt measures as 0.077" (2mm). The felt I have was purchased at Joann's Fabric Shop and is sold by the yard. It's 36" wide and is available in many colours.

The foam was purchased at The Foam Factory. https://www.thefoamfactory.com/opencellfoam/charcoal-R.html

The annulus dimensions are: I.D. = 61.5mm (2.42"); O.D. = 86mm (3.39")

The voice coil inside diameter is 26mm (1.022")

Currently, there is a web page in progress which will try to explain the audible differences, if any, between the two coils and magnets. I'm sure that Wharfedale had a reason for the differences. A sensitivity test shows that, at 1w1m, there is no appreciable difference. Those tests were run at the impedance of the driver at 4khz. See figs 1 and 2 in this page.

https://www.ln271828.net/wharfedale_super_3__P1P2J1J2.htm

Robert

 

[banddot]

I’m restoring a Wharfedale 3-way system and the Super 3’s are next up in line for restoration. I was able to restore a pair of W15FS’s to working condition with the help of @klipschorn and now I’m documenting the restoration of the super 3’s.

I have a pair of the Super 3’s but they are slightly different. Here’s the first one: View attachment 2516182 View attachment 2516183 View attachment 2516184 View attachment 2516185 View attachment 2516186

And here’s the second one: View attachment 2516188View attachment 2516189View attachment 2516190View attachment 2516191View attachment 2516192

The first one says 14,500 lines and has a longer speech coil while the second says 13,000 and has a shorter voice coil. They were both made in 1958 but the first one was made in December and the second in June. They both read just above 9ohms. Do you think these will sound alike once restored? Will the one with less lines and a shorter voice coil roll off quicker than the 14,500 lines one?

Robert, I will once again require your expertise to guide me through the refoaming (or reFelting) of these drivers. I did see your page about the super 3’s but I have more than a few questions regarding the work you put into getting them functioning again. Primarily, what is the thickness of the felt you used and What thickness was the foam you used to cute the new spider from?

-Ernie

Hi Ernie,

How did you get on with the restoration in the end?

I have acquired a set of Airedales - unfortunately the Super 8's and Super 3's have seen better days. They're both the Alnico models.

Wondering if you had success in restoration yours?

Best

 

[klipschorn]

I’m restoring a Wharfedale 3-way system and the Super 3’s are next up in line for restoration. I was able to restore a pair of W15FS’s to working condition with the help of @klipschorn and now I’m documenting the restoration of the super 3’s.

I have a pair of the Super 3’s but they are slightly different. Here’s the first one: View attachment 2516182 View attachment 2516183 View attachment 2516184 View attachment 2516185 View attachment 2516186

And here’s the second one: View attachment 2516188View attachment 2516189View attachment 2516190View attachment 2516191View attachment 2516192

The first one says 14,500 lines and has a longer speech coil while the second says 13,000 and has a shorter voice coil. They were both made in 1958 but the first one was made in December and the second in June. They both read just above 9ohms. Do you think these will sound alike once restored? Will the one with less lines and a shorter voice coil roll off quicker than the 14,500 lines one?

Robert, I will once again require your expertise to guide me through the refoaming (or reFelting) of these drivers. I did see your page about the super 3’s but I have more than a few questions regarding the work you put into getting them functioning again. Primarily, what is the thickness of the felt you used and What thickness was the foam you used to cute the new spider from?

-Ernie

Hello Ernie. Long time, no see.

The foam is about 1/8th thick (thin) 0.125" 3mm and the felt is about 1/16th inch 0.0625" 2mm. Don't use a thicker felt as this will raise the coil too far above the top plate.

 

[angelaudio]

Hi Ernie,

How did you get on with the restoration in the end?

I have acquired a set of Airedales - unfortunately the Super 8's and Super 3's have seen better days. They're both the Alnico models.

Wondering if you had success in restoration yours?

Best

This is quite a timely thread reply because I was just preparing to redo the surrounds on the super 3’s. I have thin felt but I’ll have to make sure it’s 1/16th as @klipschorn recommends. I’ll post pics as soon as I get to it. Should be within the next week.

-Ernie

 

[angelaudio]

Hello Ernie. Long time, no see.

The foam is about 1/8th thick (thin) 0.125" 3mm and the felt is about 1/16th inch 0.0625" 2mm. Don't use a thicker felt as this will raise the coil too far above the top plate.

Hey Robert! Yes it’s been a while. You cross my mind every time I play those big ole slot-loaded corner cabs with the 15” Wharfies and Super 8’s. I’ve just recently been thinking about finally making the felt suspensions for the super 3’s. I’ve got some felt but I’ll have to make sure it’s 1/16”. I’m planning on getting to it within the next week or so. I’ll tag you in the pics when I post them. I’m eager to hear these babies pumping out 100% Wharfedale magic. Hope all is well with you.

-Ernie

 

[angelaudio]

Hi Ernie,

How did you get on with the restoration in the end?

I have acquired a set of Airedales - unfortunately the Super 8's and Super 3's have seen better days. They're both the Alnico models.

Wondering if you had success in restoration yours?

Best

Post some pics, maybe they aren’t too far gone yet

 

[banddot]

Attaching some pics of mine here.

I'm told the Super 8's have continuity, but the Super 3's do not.

The Super 3's have some corrosion - I'm guessing they've sucked up a few spilt drinks in their time.

I'm taking them to a speaker repair specialist today - please all have your fingers and toes crossed for me.

Ernie - good luck with the surrounds, I'm routing for you

 

[angelaudio]

Hello Ernie. Long time, no see.

The foam is about 1/8th thick (thin) 0.125" 3mm and the felt is about 1/16th inch 0.0625" 2mm. Don't use a thicker felt as this will raise the coil too far above the top plate.

Hello Robert I was looking at the super 3 today and have a couple questions for you. First off, the felt I have is about 1mm, very thin, would that work? And second, to replace the spider, can I use the same foam I used for the wharfedale woofer?

 

[klipschorn]

The 1mm foam will work for the surround (annulus). It's only purpose is to keep the cone and coil aligned when the tweeter is aimed foreward.

If the foam is less then 1/8th inch thick (thin) it will work as a centering device. It should very lightly touch the inside of the voice coil form.

It may be a good idea to shim the voice coil with paper. If so, use a sheet about 6" long by about 2" wide. This will allow two turns of paper, 0.006" assuming 20# paper and a tube about 2" long, making it easy to remove. Once the coil is shimmed, insert the foam spider (disc); this will center the spider. Once the spider is set, remove the shim.

 

[angelaudio]

The 1mm foam will work for the surround (annulus). It's only purpose is to keep the cone and coil aligned when the tweeter is aimed foreward.

If the foam is less then 1/8th inch thick (thin) it will work as a centering device. It should very lightly touch the inside of the voice coil form.

It may be a good idea to shim the voice coil with paper. If so, use a sheet about 6" long by about 2" wide. This will allow two turns of paper, 0.006" assuming 20# paper and a tube about 2" long, making it easy to remove. Once the coil is shimmed, insert the foam spider (disc); this will center the spider. Once the spider is set, remove the shim.

And just to clarify, does the new foam spider go between these two discs?

 

[klipschorn]

And just to clarify, does the new foam spider go between these two discs?
View attachment 3026812

YES. Between the discs.

 

[angelaudio]

YES. Between the discs.

Ok so I tried something different. I used a rather rigid 1mm thick craft type non-porous foam for the spider and the annulus. I made the spider 2.61cm which is a little bit larger than the 1.012” that you referred to on one of your super 3 web pages. The foam felt just slightly snug up against the coil former. I then glued the surround in place and let it dry. I then proceeded to do the same to the other tweeter but used a 2.5cm spider instead. This spider gives very slight clearance. I then glued the annulus in the same fashion as the previous super 3 and let dry. I’m noticing that the “2.5cm spider” super 3 is slightly more compliant, probably due to the clearance in the spider. But both seem to exhibit the same output, as far as I can tell. Of course, my ears are not accurate measuring instruments.

Because of the relatively rigid or dense nature of this foam in comparison to felt, I am concerned that I am limiting xMax for the tweeter, therefore limiting the output or possibly affecting another, unknown to me, parameter. Is this a valid concern?

 

[doctorolds]

Thanks for sharing your experiences and thoughts!
I reccomend that you grab the DATS test unit from Parts Express, no affiliation. It's a very useful tool that will help you determine driver parameters and performance easily.
Tweeters do not need much xmas, they move very little in my opinion. The frequency response is important, but hard to determine with the human ear. Best of luck completing your project!

 

[angelaudio]

Thank you for the suggestion @doctorolds It looks like a very useful tool. Been wanting to educate myself on T/S parameters so this looks like the ticket

 

[klipschorn]

It'll be ok. I used to cut the spider by hand until I got the idea using two washers. Photos 5L and 5R here. https://www.ln271828.net/a_pair_of_wharfedale_super_3s%20_REV-3.htm

As for your concern for Xmax, don't be. Actually, there's essentially no unified cone motion in a tweeter, the wave propagates along the diaphragm much like whipping one end of a rope lying on the ground.

The Super 3 cone has an effective area of 4.9 square inches, or 0.00316 square meters. At 5000hz, 96dB is produced with 0.000246 inches of excursion. That's 246 micro inches, about one twelfth the thickness of a sheet of 20-pound paper.

With an excursion of 0.1mm (0.004") which would probably not be visible, the SPL would be an ear shattering 121dB

To get 121dB at 5khz from that little fella would require about 128 watts. Any sound heard would be very short as would be the life of the tweeter.

 

[angelaudio]

I like the cutting jig you made with the washers, makes for a very concentric cut. Interesting how the tweeters with the hand-cut spider had a more jagged response curve.

The response curves of the 13k line & 14.5K line super 3’s are practically identical, very interesting finding. I’m going to get a DATS unit like doctorolds mentioned because I’m curious now to know exactly what my super 3 response curves will look like. Incredible the minute amount of excursion, yet they can produce 9g’s of force. I would think they’d fall apart with those forces acting on the paper cone.

Great paper by the way. The perfect lay and square lay calculations were interesting, still studying them. I haven’t wound my own coils but it’s something I’d like to try my hand at in the future. Thanks again for all your input and calculations and experimentation, Robert. It’s nothing short of awe inspiring

 

[klipschorn]

I like the cutting jig you made with the washers, makes for a very concentric cut. Interesting how the tweeters with the hand-cut spider had a more jagged response curve.

The response curves of the 13k line & 14.5K line super 3’s are practically identical, very interesting finding. I’m going to get a DATS unit like doctorolds mentioned because I’m curious now to know exactly what my super 3 response curves will look like. Incredible the minute amount of excursion, yet they can produce 9g’s of force. I would think they’d fall apart with those forces acting on the paper cone.

Great paper by the way. The perfect lay and square lay calculations were interesting, still studying them. I haven’t wound my own coils but it’s something I’d like to try my hand at in the future. Thanks again for all your input and calculations and experimentation, Robert. It’s nothing short of awe inspiring

Your comments on that page are very much appreciated. i'll admit that most opf the stuff on that page is pure academia but interesting. Keeps my mind active. At 81, if my body worked as well as my mind, I could run a 4 minute mile.

I was also impressed by your knowing that a tweeter can experience 9g; you are the first to comment on that since I found that out decades ago. Remarkable little device, a tweeter. Consider that most commercial aircraft would likely come apart under such forces.

Actually, any loudspeaker is a remarkable device. Having only one moving part, as the cone, coil, spider and annulus are glued together, it's amazing that it can reproduce with such high quality, the sound of a 100 piece symphony orchestra. Even more remarkable is that the loudspeaker only resembles one instrument, the drum.

I'm certain you'll have a ball with that DATS.