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Advice please on 105-II recap
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T.O. Chef
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Joined: 31 Aug 2007
Posts: 179
Location: Toronto Canada

PostPosted: Sat Oct 20, 2018 1:41 am    Post subject: Reply with quote

I have changed out my B-110 for a driver with a closer to spec L(e). There's zero change in the impedance graph, so my issue is not related I surmise. There' also zero change in the listening experience.
I run a sine wave generator through them (one at a time), and there's still a distinct rise in output through the mid's all the way up to the limit of my hearing. There's dead spots in places in the HF, though the windows are narrow,

Something is either very wrong with the crossover as recapped or in the design itself, and I am exasperated trying to solve the problem. I'm not an engineer nor a speaker system designer. Obviously! (I would laugh at this point if not so disappointed). I have though recapped a great many KEF's mostly with stellar results.

I hope this chain of discussion is of help to anyone else considering recapping their 105's. I urge caution, and keep all the original cap's. You may get lucky as I twice have done with 105's, but if you have this same experience as what I now face your disappointment may be visceral. It'sNot Pleasant at all.
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Sat Oct 20, 2018 3:45 pm    Post subject: Reply with quote

T.O. Chef wrote:
Something is either very wrong with the crossover...design itself, ..


Well, that's not very likely, is it? Something has broken or changed after all these years and it is not as designed.

Why not use your sine wave generator to plot the frequency response of the voltage across each driver? You should be able to determine if it is credible. Is it rolling off the highs and lows to the midrange? What is the shaping like in the middle of the passband?

You have re-capped but have you checked the other components and all the connections and wiring?
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T.O. Chef
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Joined: 31 Aug 2007
Posts: 179
Location: Toronto Canada

PostPosted: Sun Oct 21, 2018 1:39 am    Post subject: Reply with quote

Well. Likely or Not, there's issues here.
Thanks for the suggestions Guru, but I'm afraid the technicalities are a bit beyond my abilities.

I'm now very sure that there's not any problems with my wiring or Non-changed board components.
I have just wired in a set of 105/2 boards (I just happened to have on hand) for a test.
I get the same results, though the bass seems to suffer a bit with them. Those boards have fresh cap's throughout btw, and likely need some time breaking in?

This project now gets sidelined while I reset my brain. The frustration is palatable!
Fortunately I have well recapped and refinished 104aB's and my wonderful clones of LS3/5a's to keep me company during that process..... My reference speakers that don't lie.

To Be Continued.
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