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Wharfedale W90s - How I Replaced My L-Pads

Progducer said:
Thanks for the updates Brad!
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Well, since you like updates so much, here are some more! ;)

Since I was opening a speaker this evening to recap the mids with some NOS Russian Paper In Oil caps, I decided to rewire the L-Pads so all connections were on the same channel rather than "bridged" between both channels. As of right now, I have one speaker with NOS PIOs with both mid and high L-Pads wired "bridged" as described (and shown) in the OP. The second speaker now also has NOS PIOs, however, the L-Pads are now wired with all connections on a single channel (similar to having a mono L-Pad).

I can say without hesitation it sounds better wired with only one channel connected rather than bridged. The difference is most pronounced in the High Frequency. The mids sound pretty similiar between both speakers.

Another difference between each speaker is the "single channel" L-Pad speaker needs to be set slightly higher than the speaker with the "bridged" L-Pad. For example, if the "bridged" speaker is set to 12 on the dial, the "single channel" speaker is set to approximately 2. Not certain why this would be the case however.

I am definitely going to rewire the speaker with the "bridged" L-Pad to mirror the other speaker once I receive my HF caps and can complete my W90 recap!

Here are some additional pics. If you have any questions please don't hesitate to ask!!!!!!

Regards,

Brad

PS. I took these snapshots prior to wiring in the new mid caps.











TL;DR: Buy the mono 50watt 8 ohm 1" shaft L-Pads. Stereo L-Pads are more expensive, not needed and sound slightly worse.
 
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Very interesting thread here. Thanks to the OP for sharing. Gotta say up front that I'm not that familiar with W-90's, but I'll admit I do not quite understand when the stereo L-pads are required above and beyond the mono version. I can think of other vintage acoustic suspension speakers (Rectilinear) with multiple tweets or super-tweets in the same cabinet that are controlled by a mono rheostat, so what makes these different? Are the stereo L-pads intended for use in a console?

Also, about the original controls, how was it documented that they were 50 ohm devices ...... and what was their wattage rating? Can we see pics of the final x-o installation? Great thread, thx.
 
ra.ra said:
Very interesting thread here. Thanks to the OP for sharing. Gotta say up front that I'm not that familiar with W-90's, but I'll admit I do not quite understand when the stereo L-pads are required above and beyond the mono version. I can think of other vintage acoustic suspension speakers (Rectilinear) with multiple tweets or super-tweets in the same cabinet that are controlled by a mono rheostat, so what makes these different? Are the stereo L-pads intended for use in a console?

Also, about the original controls, how was it documented that they were 50 ohm devices ...... and what was their wattage rating? Can we see pics of the final x-o installation? Great thread, thx.
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Hi ra-ra!

Thanks for joining in the discussion. First of all, I would be happy to share photos of the crossovers as they currently are, but understand, so far I've only completed the mids. I'm still waiting on my tweeter caps to arrive. I ordered them from Estonia and unfortunately they seem to be lost somewhere between Eastern Europe and Massachusetts! Nonetheless, I'll post some pics of the current state of my crossovers tomorrow.

Switching topics to the L-Pads, everything that I've read on AK about the W90 pads state they are 50ohm. In regards to wattage handling of the originals, I am not sure, however the speakers themselves are rated at 40 watts (I believe).

When I determined that my pads were in need of either massive surgery or replacement, I read (and read and read...) as much as I could on AK about W90 L-Pads. A few of the threads I read are linked in the OP. After my research on the forums I felt pretty confident that the L-Pads sold by Parts Express would work for this application. When I placed my order, I ordered stereo pads because they visually resembled the originals (stacked layers)... hence my mistake. ;)

After I installed the replacements and posted my work, PastTechFan (THANKFULY) commented that L-Pads from this era (early 1960s) were created by stacking potentiometers and bridging them. This is unlike modern L-Pads that can achieve the same result in a single layer. So this means the original is designed totally different than the modern L-Pads. This is the case even if visually the original compares to a modern stereo L-Pad due to having 2 stacked layers.

How 50 ohm stacked potentiometers compare to 8ohm L-Pads still needs to be discussed and captured on AK for owners who may experience similar issues with their L-Pads in the future. Personally I haven't seen an explanation written on why the 8 ohm L-Pad is an adequate replacement......only the statement that it is.

This discussion is great, as I hope we ultimately capture in this thread the specifics of what the original Wharfedale "W" Series pads are and which modern pads are best as replacements for them.
 
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Thanks for your "woodshedding"! Your work has inspired me to replace my pads too.I had worked very diligently on cleaning the originals with minimal improvement.I was very pleased with the PIO cap replacements,luckily I got mine in about 8 days.Hope yours come soon.
 
Hey phatster!

Thanks for the compliments. It's great to add to this community that has helped myself and so many others. The mono 50 watt L-Pads cost $10.90 each, so for under $50 (including shipping) you can replace the original ones. Here is the link:

http://www.parts-express.com/parts-express-speaker-l-pad-attenuator-50w-mono-1-shaft-8-ohm--260-255

Make sure if you decide to go this route to buy the 1" shaft model. The 3/8" will definitely be too short.

Since the mono pads are the same width/diameter as the stereo pads (just shorter being one channel) the installation pictures in the original post are valid. If you have any questions just ask!

Best Regards,

Brad
 
bce22 said:
Hi Prog.

..... What I can say with very very little time spent in front of them they sound incredibly smooth and musical. I LOVE this sound! ..... this evening I rewired the stereo L-Pads in one speaker to use only one set of terminals. I think it sounds better this way, especially in the highs. I took lots of pics and will add them to this thread once I get back to a real PC.

So, I can say with conviction that if you are going to replace the L-Pads definitely go with the mono ones. I made a mistake with the stereo ones.
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Hey, great to hear your progress on the 90s. :trebon: Sweet, sweet.

Looking forward to news of those Estonian caps.

-Keith
 
So my friends, yesterday my replacement Super 3 tweeters arrived. Since I was opening them up to do the ole switcheroo, I decided to rewire the other L-Pad to only use one channel of these stereo L-Pads as well.

Now that I've spent more quality time with these new pads, I feel 100% confident in saying these new L-Pads lead to better sound over my original ones. I know this is subjective, and I acknowledge that I have made a fair amount of changes to these speakers AND I also agree that the condition of my original L-Pads may be worse than others, but even with all that said, I think it's totally a worthy update/upgrade to make.

I mean 4 mono L-Pads from Parts Express shipped is under 50 bucks!!! Installation is really straight forward too. Those with soldering irons and a few bucks and some Wharfies should take notice!!!
 
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PastTechFan said:
Are you going to stack'em?
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Gotta try it right!? I'll run them off my sweet sounding Sony STR-7065, but I'll have my Scott 222D in a couple weeks to take over the job. I'll have pictures by the weekend of the stack. The newly acquired pair have that strange european terminal connector, so I need to get binding posts in there before I can hook it all up.
 
Progducer said:
Are the terminals on the original L-pads also labeled with 1/2/3 as the new ones are?
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Hey Prog!

The originals aren't numbered like the new ones, however there is a wiring diagram on the side of the new L-Pad box. Comparing the diagram to the original lpad wiring it is identical.

Cap to #3
Speaker to #2
Ground to #1

Easy peasy!:thumbsup:

Make sure you come back and let us know your experience with getting them installed. And how they sound!:music:
 
There are three 50ohm L-pads on Epay right now under the title "50ohm Linear Taper 100 Watt Wirewound Mono L-Pad Hardware Supplied 3/8" Shaft"
 
I know that they are not long enough, but dont you think it would be worth using the original 50ohm value resistance to keep the xover all original? Seems like it would be worth digging into that wood panel a bit. I contacted that epay seller and he is looking around for more. He says he has a ton of NOS pads, just needs to measure resistance to find which ones are 50ohm.
 
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Let me know if he finds some that are 50ohm with the 1" shafts please. No worries if he doesn't find some as the ones mentioned prior should be fine.
 
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