Can't get back panel back on Wharfedale w70 speaker

[Sam08861]

Hey all,


Just finished recapping a pair over early Wharfedale W70s and replacng the 4uf PIO caps with KGBs. However, I can't get one of the back panels back into the cabinet.

6 months or so ago, I'd taken a break from my vintage gear for a while, but now getting back into it. When I took a break, I left the back panels off. Nothing was on top of the speakers.

It seems that either the panel mysteriosly go longer or the cabinet top got bowed? It seems like the while panel is 1mm too tall. Tried switching panels with the other speaker, no difference.

Any suggestions appreciated!

 

[sKiZo]

Maybe try the same trick they do with metal ... put the cabs in a warm room so they expand, and put the backs outside. Just checked your weather report for NJ (below freezing), so this is a good time for that ... shouldn't take long to experience significant shrinkage ... ;-}

 

[Sam08861]

Thanks skizo,

That's a great idea.

With the panel having the crossover/input wires soldered in already, I was hoping to avoid having to resolder but may give that a shot if there's no other suggestions.

 

[rogerfederer]

sand them down a touch and voila

 

[Sam08861]

Thanks Roger, I thought of that too, but feared they would shrink back and leave gaps when done or get dust int he cabinet, necessitating removing the back/re soldering to prevent it.

I'll try putting the speaker box face down, that should give me a bit more control and maybe I can wedge thin piece of metal or a spatula to slip/force it in.

 

[sKiZo]

Yours vented or not? Seems to me, they made both at one time or another. If vented, slightly loose shouldn't be an issue, long as it doesn't rattle. If not, you'll need a tight seal.

Another suggestion ... chamfer both sides of the rear panel all around before installing it, and do the same with the inside edge of the case. That should make it a whole lot easier to fit the panel and give you a nice groove to rub in some black silicone for a nice tight seal. Mask off the groove first, and you can get a nice clean edge, and it'll be fairly easy to remove if you ever have to do it again - just cut the silicone bead with a razor blade.

Also, you don't want to force the panel in too much ... I can guarantee you'll be very unhappy if you split the corners of the case.

 

[Sam08861]

Skizo, I am ported, so your're right about that!

Putting them face down allowed me to insert the panels evenly on all sides and it went right in.

Sam

 

[Ghonk]

Well i will have to remember not to do that.
Are your's the radio people ones.

 

[Sam08861]

They are from BIC and had alnico woofer, mids and super 3 tweeters. Replaced the 2x2uf oil caps with KGB 4uf and cleaned out the pots while I wan in there.

 

[Ghonk]

I have PIO for mine,need to get my head out of my ass and install them.

How do you like your's now,vs the original caps?

 

[Sam08861]

Hi Gonk,

I only listened to the speakers for a few moments before replacing the caps as the pots were shot so could't hear much treble and one woofer wasn't firing. Unfortunately I rehabbed them fully while I had them open instead of giving the old caps a chance.

I did keep them as I feel like they have a vintage military look.


Below is what the new 4uf KGB next to the old 2uf stock units. Surprisingly smaller.



Maybe if I"m feeling adventurous in the future, I'll swap them back in.

While I can't say say how they compare, the speakers sound 'big' and the mids are killer. High's are also nice. The bass can get a bit boomy, but I am in a small 10x10 room that is my office/workshop with hard floors and windows on 2 walls so haven't tried them in a bigger room. Some of this may be contributed to by the idler turntable and phono stage of the amp.

Sam

 

[Scarberian]

The panels can expand with moisture, or the cabinet shrink with dry air. Either way, they are a tight fit.
This worked for my W90 when I recapped them and the panels were being difficult to replace.

Put some furniture wax on the mating edges, both panel and cabinet. This should help them slide in. Apply, let it dry for 5 minutes, then polish it to a slick shine.

If that doesn't work, try altering the humidity in the room. I would think dryer is better.

 

[PastTechFan]

.......I did keep them as I feel like they have a vintage military look.

View attachment 871028

Maybe if I"m feeling adventurous in the future, I'll swap them back in......

Pretty sure that's His (her?) Majesty's "Broad Arrow" mark on those caps. If so, those aren't just "military look", but actual military surplus. Glad you kept them. They might still be good. Can you test them?

 

[Sam08861]

Hi PasTechFan,

Thanks for the info.

I don't have a capacitor checker but do have a regular multimeter, vtvm, etc but not sure how to check them using those tools. Would be glad to do so though, if there's a procedure to check with those tools.

Sam

 

[markkb]

Not to be picky but I think the caps are KBG. We've got KGB on the brain from the Cold War. I have those in my W60's and they sound very nice. I'm still working on my W70s, looking forward to those.

 

[Sam08861]

You are absolutely right, they are KBGs but I had read that these were high spec items manufactured specifically for postwar KGB surveillance equipment (don't know if that's true or just internet folklore) and must've stuck in my head.