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Do Quad Electrostatics Come To An End of Life?

I have lived with Quads for 20 years. The first five years were with the 989s and we shall draw a discrete veil over them. Shipped across the country regularly for repair, until eventually the distributor made me an offer on a set of 2905s to let me get rid of them. The 2905s were totally different, and completely reliable for 15 years. Then a panel started arcing, and I was lucky to get it repaired in province after two six hour drives. Cost ~$900CDN excluding the gas! Now a different panel is doing the same thing. The last one had an adhesive failure along the edge, such that the Mylar could flap in the breeze. I don't play them very loud, and only have 40W power amps. But materials science being what I imagine it to be, I'm thinking the adhesive on the other panels is likely to go the same way, That means potentially ten more panels after the two that have already failed, ie 4.5kCDN plus labour to replace the final ten. I see used 2905s for that price, though shipping these monsters is likely to add a massive extra cost. My neighbour used to be a concert pianist, and still plays in her seventies with a local ensemble. She visits and says she feels there is a piano in the room. They are that clear, and uncoloured.

The alternative is to own a pair of expensive paperweights and go back to the DCM TimeFrame TF700s that preceded all the Quads. I'm listening to them right now and I do still like them. They add some softening and colouration but still do better than any box speakers I've heard. They are a little battered since a long-deceased Burmese cat used to like to sharpen his claws on the speaker cloth, but I can strip that off and paint the MDF. There's no kids or cats around to poke the speaker cones.

I think I'll repair the current broken panel in the 2905s, but if more failures come after that I think I'll write them off as 15 years of glory and get used to speaker cones again. Has anyone else been a long term owner of Quads and can give advice as to what I should expect from them in terms of falling apart all at once?

dogberry
dogberry OP
647 posts
 

No, not turned on all the time. Sheldon Stokes is in the USA, but if I can, it would be easier to do this in Canada. My repair man would likely be perfectly happy to replace all the panels in one go. The question really is this - is this likely to be necessary?

hamr
56 posts
 

Turn them off after each use and then turn on when using. They will last for a very very long time and only take 5 secs to charge 

dogberry OP
647 posts
 

That's what I've been doing for the last 15 years!

mwjones's avatar
mwjones
37 posts
 

How about calling Sheldon for his advice? He's quite friendly and I'm sure if you explain your concerns, he can help even if you don't wan't to vacation to New Hampshire with your quads...

dogberry OP
647 posts
 

I think it would be an imposition to pick his brains when there's no likelihood I will use his services. Maybe I'm over-polite, but I wouldn't do that. In the interim, my repair guy has replied to me:

I've done a bit of digging, and according to some technicians, the glue that holds the stators to the latticework becomes brittle with age, and transport/shipping can jar it loose, though it can also fail by other means. This ties in with your findings about increased issues after an active session. The pops are the diaphragm contacting the stator(s) and shorting the HV. 
 
I pulled the old panel out of the Archives for closer investigation. Stripping it down revealed that the position of the arc coincided with a sagging stator front and back, and the glue is indeed brittle. I can easily see vibration (from music or transport) breaking more of it free. The panel we replaced last time has a totalled diaphragm (a sizable hole burned right through). I don't know whether the absence (thus far) of full-time sizzle in this lower panel indicates that the diaphragm is not yet punctured. If it isn't punctured, it is possible that re-gluing the stator may resolve the issue, but I've only got a foggy shape of a plan for how to do that at this stage. If the diaphragm is punctured, it may not be feasible.
 
I don't believe I have the capability to rebuild damaged panels at this stage, though there are outfits that offer such services (SDS Audio Labs, for example). There are also kits available for the DIYer (such as from ER Audio), but they require a lot of space and the time required for me to undertake that work would likely push the repair into the 'uneconomical' territory. Also, I get worried just looking at the details of what's involved (one wrong move and it's back to square one again). At this stage, I can replace panels, but I can't repair them.
 
It is a valid hypothesis that shipping/transporting the unit(s) will make the issue worse - these things are fragile even when new - and I'm worried about the same if they were to visit me again. I don't, as a rule, do house-calls anymore, but this may be an extenuating circumstance and I'd be willing to look into that option for you.
 
I wish I could provide an easy, cheap, and surefire solution, but I don't think that one exists for this. I was hoping you just had that one bad panel that didn't get enough glue during manufacturing (or something). However, it's looking like a systemic or time-dependent issue with these units (or this one unit's panels, if it's the same speaker as before). 
I don't think there was an issue related to transport: the first panel failed when the speakers had lived in one spot for 15 years. The second failed after two months back at home.
So I plan to let him replace this panel (it is the same speaker, but a different panel, so not an issue with the quality of his work). But when the next one goes, I guess I have to decide whether I own a pair of expensive paperweights, or whether I replace all remaining ten panels. I don't mind an excuse to visit him, despite the long drive, as he is a fascinating character as well as a skilled speaker and amplifier repair man. If we lived closer I'd be delighted to be his friend.
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