Wharfedale W70 project

[Gang-Twanger]

Nice job! My compliments to the wood chef.

I like the isolator cups for the Super 3. One of the cool things about the Super 3 (the alnico version, at least... Haven't heard the ceramic one yet) is the fact that it can be used facing out OR up, and it can also be used in free-air applications as well as the semi-gazebo-style setup in the early W90. A very-flexible driver. It's only requirement seems to be the height, whether that's taken care of in the design of the speaker or afterwards by way of stands. But one of my favorite qualities about the alnico Super 3 is the way it deals with the various kinds of distortion and artifacts found on recordings from the '50's, '60's, and '70's. It's like it somehow filters out the bad stuff and keeps the good stuff.

 

[EddyR]

On a set of W-70's I had many years ago I glued a plastic pot over the back of the 8" midrange and it tightened up the bass a lot. I did one first to test it and then did the other one. Over the years I have tried open back midranges and they all sounded better with the back sealed in bass and midrange.
Ed

 

[leesonic]

DRAT!

Got a bad capacitor. I was testing some of the Russian oil-filled caps I have in preparation for making the crossover for this project. It was going to be four 1uF caps in parallel. Seven tested fine, one of them seemed SO far out, there must be something wrong with it. I hate to buy just one off eBay, I was tempted to use the 4uF films I have in stock, but I've heard these caps sound so right with these old drivers. Maybe I can find one if I place an ad on Barter Town? Or a pair of similar 1uF?

The tested values were :

nF, Vloss, ESR
921.6, 0.2, 0.56
963.8, 0.2, 0.56
994.8, 0.2, 0.57
985.2, 0.2, 0.74
1015, 0.3, 0.63
958.3, 0.2, 0.57
1014, 0.2, 0.61
1981, 6.7, 7.0 * this is the bad one

 

[leesonic]

Crossovers with Russian PIO caps

Got the crossovers finished late last night. Four green 1uF Russian caps, with a larger 0.1uF thrown in for good measure. I think the inductors for the woofers and the L-pads are original.

Six of the caps I got when I bought the drivers. I ordered two more from eBay seller elecments13. They were shipped from Bulgaria, and arrived in one week. Very pleased with their service.

Lee.

 

[leesonic]

Finally got them together this afternoon. First impressions? Way way way too much midrange, it almost hurts the ears, especially compared to the Dynaco A50s they are sitting next to. I dug out an old Pioneer equalizer that was destined to donate it's case for another project. By making a sort of smiley face type EQ curve, I could tame the midrange somewhat. It seemed to need turning down around the 1kHz and 2.4kHz bands. I actually didn't need to boost the bass, there is quite a decent amount from the 12" woofer and 10" mid-woofer. Perhaps my fears of running the middle driver full range have been confirmed.

It's funny, they are actually being driven by a bunch of misfit toys. A NAD 314 with a bad power amp section, and a NAD 3140 with a bad preamp section. Source is a Sony CD Walkman, which has a 1-bit DAC and I've always liked the sound of. The subwoofer in the center? Just a project I built about 10 years ago or more, consisting of an Infinity car subwoofer, a plate amp from Parts Express, and a box I made from 3/4" plywood. It wasn't connected for the listening test, in fact, I can't remember the last time I used it.

Lee.

 

[BilboBaggins]

Lee,

Any progress in taming the midrange? My only suggestion would be to try an L-Pad. And I really know nothing about designing speakers or tweaking them, for that matter.

 

[Brian]

Yeah, he missed the l-pad from the original crossover. Also, dump the subwoofer and move out the other speakers from the room while working on the project. The cabinet is still smaller than the W70 so I would expect some loss of low end.

The l-pad does not effect the woofer so it is not the issue but does the tweeter level. This may be a bit of the midrange issues. If I understand what I see, you are running 5mfd of caps. This will change the frequency response of the tweeter and it maybe also part of the problem. That is an increase of some.20% of capacitance value.

Lastly, try something better than the NAD. I have found that on a number of vintage speakers they seem to run somewhat bass thin.

 

[drbiggles]

Hey Lee,

In regards to a conversation from another thread, about this project, I thought I'd stop by with a few thoughts. I had an early W70 project pair that I did a lot of work with. As previously stated in this thread, the early versions had both the woofer and midrange running full range, no crossover. And no separate enclosure over the back of the midrange. I sent my alnico drivers to DC70 and he was able to give me the T/S parameters for them. I also gave him a ceramic Super 3 so I could see the difference between that and the alnico version.

Knowing what I know now, I would have been able to suggest a few things that might have been able to pull something out of your existing cabinets. I went back and reread the thread and it sounded like you just had a 4uf capacitor on the tweeter? At 8 ohms, that would have crossed it over at approximately 5k. This would explain all that darned midrange, no highs to balance it all out. It was believed back in the 50's and into the 60's, that if you crossed the woofer over to the midrange at 800Hz, the backwaves between the two wouldn't have confused each other. So, put an inductor on the woofer to limit it to 800Hz. Put an inductor on the midrange to limit it to 2500Hz, and a capacitor to filter out frequencies below 800Hz. Now the woofer and the midrange don't have to work so hard, they can work within their sweet spot. Bring the Super 3 down to 2500Hz to meet the midrange. The Super 3 does have a spike around 9k, so build a Zobel network for it to smooth out the frequency response. That should have balanced out the drivers and made a really decent setup.

In working with similar era Bozak drivers, I still find the backwaves between the woofer and mid pound on each other. You wind up with a very confused midrange, all flubby without much required detail. Once you build a cover over the back of the mid, it mid comes alive and really shines just as it was designed to do.

Of course this is all moot now. I ended up buying the tweeters and mids off you, plus you tossed in the oil caps as a gift.

I sold my W70's off, so I don't have any either. But given how easy these things are to find, I'll drag home another pair. I want to build my own W70, Super Sized. DC270's tests showed that the woofer would like to have at least 5 cubic feet to play with. So, I figured I'd find a pair of vintage, furniture grade cabinets that are 5 to 7 cubic feet and build them into that. I'd put an enclosure over the back of the mid and I may use this crossover that DC2070 suggested. I'm running an alnico Super 3 in my Trusonic project and they sound fantastic crossed over at 2500Hz.

Biggles

 

[Ghonk]

When i eventually get the PIO caps put in my 70's,which i know the dr. loves ,would you recommend putting a bowl over the mid.

And if you do would it need to be a certain size,or would anything work as long as it isolates the mid?

This would be the ONLY mod,no changing caps or building a crossover.
Mine only have the 1 pot,so i assume the woofer and mid run full range.

 

[drbiggles]

Hey Ghonk,

The midrange in the early W70's is a really large midrange, it's an 8" rig. If you were to build an enclosure that barely covered the back of the driver, you'd lose valuable internal cabinet space. Cabinet space you simply cannot afford to lose, no way no how.

I think if I had to work with an original W70 cabinet, I would make a real 3-way crossover for it. Cross the woofer over at 800Hz, bring in the mid and let it go up to 3k, give or take. Just a simple first order crossover, nothing space age. Supposedly, at 800Hz the woofer and mid won't screw with each other too much. I really think it would be a great project to see what you could do with the original layout.

Biggles

 

[leesonic]

Fixed the dead picture links now that this thread has a new lease of life.

If you plan on making an enclosure for a midrange, see if you can get a thick cardboard tube of 8" diameter, or even a piece of PVC pipe? On my AR9LSi's, it's just that, a cardboard tube with a circle of MDF glued into the back of it.

Drbiggles, that crossover you posted above, do you have another version with the Zobel network in it? You know, you could always sell me back the mids and tweeters I sold you...

Lee.

 

[drbiggles]

Hey man!

Yay on the pictures! Yes, I have the Zobel specs around here somewhere, will dig them up later today. I wrote it down on paper. You're more than welcome to your midrange drivers, but your Super 3's are in my Wharfedale Super 12 project. By the way, the ceramic versus the alnico Super 3 come in nearly identical in the T/S parameters. Our ears will not be able to tell the difference. That being said, I would suggest going with a modern tweeter solution. The Super 3 prices on fleabay have gone through the roof. Unless you can source a pair out of a local pair of W70's, I wouldn't bother.

Here are the two modern tweeter solutions I would suggest. I'm using the SEAS in a Bozak Symphony project, and the Hiquphon I'm going to put into another Bozak project.

http://www.seas.no/index.php?option...6-t25cf001&catid=50:excel-tweeters&Itemid=360

http://www.hiquphon.dk/page1.html
http://www.hiquphon.dk/page1.html
Here is how I handled the midrange enclosure on a pair of vintage DIY Bozak B302A's. It's an 8" concrete piling cardboard tube form I bought at a local hardware store for way cheap. For the 6" Bozak B209B midrange I did 452 cubic inches lined with 1" thick cotton batting. I doubt if this particular tube will work for an 8" driver. It's too small for Bozak's B800 8" midrange.

I've also included a few pictures of the external Alnico Super 3 tweeters for my little Trusonics project. The external crossover has an l-pad to adjust, I didn't know how bright it was going to be. The difference between having and not having the Zobel network in the crossover was like night and day. The Super 3's dropped into the realm of being very smooth in response across their range, wonderful. There isn't one Super 3 on the planet that sounds as good as these.

Biggles

Biggles

 

[drbiggles]

Hey,

Here's the Zobel Network that I made for the Super 3. Capacitor is a 4uF and the resistor is a 10 watt, 8ohm. It wants to sit closest to the tweeter, schematic can be found here.

http://www.wavecor.com/html/zobel_networks.html

I should also be using test equipment to map out the response of the tweeter to see how the Zobel network is affecting it and choose a capacitor value based up on that. Some day, I will get to that. For now, this setup has really helped the tweeter and is tons smoother. Considering the cost of the parts, redoing things later is of no issue.

Biggles

 

[Proengineer]

I know I am late to this thread, but there is an error here. The Wharfedale W70D's series were not ported cabs. They were an "Acoustic Suspension"loudspeaker and were sealed cabinets. No ports! The W70D mid/bass was closed via a plastic cup type that sealed the driver, while ther W70D MKii were enclosed with a paper tube. Neither of which speaker was ported in any way. Hence: Acoustic Suspension. This comes right out of the original brochure I have in front of me now.

 

[Dean Halleck]

Hello , I'm late too - 2022 - (LOL) , I've been all around this great big internet and I've seen all kinds of W70's................... - ( reminds me of a Beach Boy's song ).... Anyway - Wharfedale made several different W70 Loudspeakers, Some with 3 drivers , Some with 4 drivers.... Some with enclosures around drivers , and some without those enclosures . . . And some Were Ported and some were not , Unfortunately Wharfedale was not good at labeling the different W70 Speakers -

- Pictures!

 

[leesonic]

I know I am late to this thread, but there is an error here. The Wharfedale W70D's series were not ported cabs. They were an "Acoustic Suspension"loudspeaker and were sealed cabinets. No ports! The W70D mid/bass was closed via a plastic cup type that sealed the driver, while ther W70D MKii were enclosed with a paper tube. Neither of which speaker was ported in any way. Hence: Acoustic Suspension. This comes right out of the original brochure I have in front of me now.

Enclosed with a paper tube IS ported. Unless that paper tube goes nowhere, in which case, why would they put it there?

The brochure below says that the W70D uses the 8" midrange driver as a passive radiator for upper bass frequencies, so even this system isn't technically acoustic suspension either.

 

[Dean Halleck]

Hello, I'm thinking we aren't communicating very well - LOL

- they made at least 4 or 5 different different versions of the W70 Loudspeaker, some were ported and some were not ---- yours may be , but mine is not ported .....

- some have one L-Pad and some had two L-Pads.....

- some looked like they had 4 drivers or 3 drivers with a passive radiator..... and some like mine only have 3 drivers... just trying to help -

 

[Dean Halleck]

- I've been talking to a Forum member here named " klipschorn " , he's one of the more knowledgeable people here on Wharfedale Speakers and he told me that they made Six different W70 model speakers... First model W70 and then Models W70 models A -E . . .

So it appears that Six versions of the W70 Loudspeaker were made -- W70 , W70a , W70b , W70c , W70d , and W70e....


- Now if we can just get pictures and descriptions of each model - that would be awesome! -



Thank you,
Best regards, Dean

 

[CJ Payne]

My W70C's are acoustic suspension, three drivers, however the 8" is definitely not a passive radiator. It is very much an active driver. However to muddy the waters I've understood that even the sub-variants of the W70's went through their own changes over time, and that my 1964 W70C's might be different from a W70C made later in the decade.

 

[telejunky]

My W70C's are acoustic suspension, three drivers, however the 8" is definitely not a passive radiator. It is very much an active driver. However to muddy the waters I've understood that even the sub-variants of the W70's went through their own changes over time, and that my 1964 W70C's might be different from a W70C made later in the decade.

I have two pairs of W-70c's. One has a better crossover with two inductors and two caps. I've added bowls over the alnico mids and this pair sounds very very nice.

The other pair was probably assembled on friday late afternoon on a three day weekend. The pair have different midrange and different crossovers. This pair is doing garage duty until I can assemble the parts needed to make them right. I do have a pair of Bozak b800's sitting around and I'm tempted to do a Bozedale (or would that be Wharfezak?).